WO2026022572A1

WO2026022572A1 - Catheter flex circuit and trace configuration

Info

Publication number: WO2026022572A1
Application number: PCT/IB2025/056888
Authority: WO
Inventors: Angela N. WHELAN; Bryce W. BUNKERS
Original assignee: Medtronic Inc
Current assignee: Medtronic Inc
Priority date: 2024-07-25
Filing date: 2025-07-08
Publication date: 2026-01-29
Anticipated expiration: 2027-01-25

Abstract

In some examples, a medical system includes a handle, an elongated body, a plurality of electrodes, and a flex circuit extending at least between the handle and a distal portion of the elongated body. The flex circuit includes an elongated substrate defining a first face and a second face opposite the first face. The flex circuit includes a plurality of trace elements electrically connected to the electrodes. A first group of trace elements is disposed on the first face of the elongated substrate. The first group of trace elements are electrically connected to a first group of electrodes. A second group of trace elements is disposed on the second face of the elongated substrate. The second group of trace elements are electrically connected to a second group of electrodes. When activated, the first group of electrodes and the second group of electrodes have a different polarity.

Description

CATHETER FLEX CIRCUIT AND TRACE CONFIGURATION

[0001] This application claims the benefit of U.S. Provisional Patent Application Serial No. 63/675,613, filed July 25, 2024, the entire content of which is incorporated herein by reference.

TECHNICAL FIELD

[0002] The disclosure relates to ablation of tissue.

BACKGROUND

[0003] Cardiac ablation is a procedure that may be employed to treat an irregular heart rhythm (e.g., an arrhythmia). Cardiac ablation may involve alteration of cardiac tissue to disrupt generation and/or propagation of faulty electrical signals causing the arrhythmia. Ablation devices may include catheters with one or more electrodes. The electrodes may be configured to direct ablation energy to tissue of a patient to cause a lesion in the tissue, for example to block unwanted propagation of electrical signals.

SUMMARY

[0004] This disclosure describes example medical devices and systems configured to deliver energy (e.g., ablation energy) to one or more areas of tissue (e.g., cardiac tissue) of a patient. The medical systems and devices described herein can include one or more catheters configured to be introduced into a patient and navigated to target tissue to perform a medical procedure (e.g., cardiac ablation).

[0005] In examples described herein, a catheter includes trace elements (e.g., instead of wires) disposed on a flex circuit to connect processing circuitry and/or energy generation circuitry to the sensors and/or delivery elements (e.g., electrodes, transducers, structures configured to transmit energy, and the like). Using trace elements and a flex circuit as opposed to wires to connect the circuitry and the sensors and/or delivery elements may reduce or even eliminate a risk of unwanted electrical shorting (e.g., electrical connection) between certain portions of conductors of the trace elements.

[0006] In applications with relatively high voltage (e.g., equal to or greater than 1200 volts, such as 1500 volts and greater) and/or relatively high current, decreasing and/or eliminating a risk of unwanted electrical shorting can help ensure efficacious and uninterrupted energy (e.g., as part of a cardiac ablation procedure) to a patient. Additionally or alternatively, using a flex circuit to connect the circuitry and the sensors and/or delivery elements can increase the mechanical robustness of the catheter (e.g., in response to various forces experienced by the catheter), as compared to wires. Additionally, trace elements and a flex circuit provide a relatively small form factor (e.g., as compared to individual wires), which may enable a reduced cross-sectional area of at least a portion of the catheter. A reduced cross-sectional area of the catheter may facilitate relatively easy introduction and/or navigation of the catheter to target tissue of the patient. Additionally or alternatively, a reduced cross-sectional area of the catheter may enable the use of additional system components (e.g., more conductors to supply more delivery elements such as electrodes, and/or more sensors), which would otherwise not be possible due to space constraints when using wires.

[0007] In some examples herein, the trace elements and corresponding sensors and/or delivery elements are positioned and/or organized on the elongated substrate to reduce or even eliminate chances of unwanted electrical shorting between particular trace elements. In some cases, unwanted electrical shorting can occur between trace elements having different polarities when such trace elements come into contact. In some examples described herein, trace elements corresponding to electrodes having different polarity are disposed on opposite faces of the elongated substrate of the flex circuit. The elongated substrate can be sized, shaped, and/otherwise configured to electrically insulate respective groups of trace elements, such as to prevent unwanted electrical shorting (e.g., such as during period in which electrical signals are delivered to the electrodes via the electrical trace elements). In some examples, trace elements are additionally or alternatively grouped on lateral sides of the elongated substrate, such as grouped according to those trace elements and electrodes that are active during a given time period (e.g., a first time period and a second time period).

[0008] In some examples, a medical system includes a medical system includes a handle; an elongated body; a plurality of electrodes at a distal portion of the elongated body; and a flex circuit extending at least between the handle and the distal portion of the elongated body, the flex circuit including: an elongated substrate defining at least a first face and a second face opposite the first face; and a plurality of trace elements disposed on the elongated substrate, each of the plurality of trace elements electrically connected to at least one electrode of the plurality of electrodes, wherein a first group of trace elements of the plurality of trace elements is disposed on the first face of the elongated substrate, the first group of trace elements electrically connected to a first group of electrodes of the plurality of electrodes, wherein a second group of trace elements of the plurality of trace elements is disposed on the second face of the elongated substrate, the second group of trace elements electrically connected to a second group of electrodes the plurality of electrodes, and wherein, when activated, the first group of electrodes and the second group of electrodes have a different polarity.

[0009] In some examples, a method includes introducing a medical system into vasculature of a patient, the medical system including: a handle, an elongated body, a plurality of electrodes at a distal portion of the elongated body; and a flex circuit extending at least between the handle and the distal portion of the elongated body, the flex circuit including, an elongated substrate defining at least a first face and a second face opposite the first face, and a plurality of trace elements disposed on the elongated substrate, each of the plurality of trace elements electrically connected to at least one electrode of the plurality of electrodes, wherein a first group of trace elements of the plurality of trace elements is disposed on the first face of the elongated substrate, the first group of trace elements electrically connected to a first group of electrodes of the plurality of electrodes, wherein a second group of trace elements of the plurality of trace elements is disposed on the second face of the elongated substrate, the second group of trace elements electrically connected to a second group of electrodes the plurality of electrodes, and wherein, when activated, the first group of electrodes and the second group of electrodes have a different polarity; and advancing the medical system through the vasculature until the distal portion is at or near target tissue within the patient.

[0010] In some examples, a medical system includes a handle; an elongated body; a plurality of electrodes at a distal portion of the elongated body; a flex circuit extending at least between the handle and the distal portion of the elongated body, the flex circuit including: an elongated substrate defining at least a first face and a second face, and a plurality of trace elements disposed on the elongated substrate, each of the plurality of trace elements electrically connected to at least one electrode of the plurality of electrodes, wherein a first group of trace elements of the plurality of trace elements is disposed on the first face of the elongated substrate, the first group of trace elements electrically connected to a first group of electrodes of the plurality of electrodes, wherein a second group of trace elements of the plurality of trace elements is disposed on the second face of the elongated substrate opposite the first face, the second group of trace elements electrically connected to a second group of electrodes the plurality of electrodes, wherein a third group of trace elements of the plurality of trace elements is disposed on the first face of the elongated substrate, the third group of trace elements electrically connected to a third group of electrodes of the plurality of electrodes, and wherein a fourth group of trace elements of the plurality of trace elements is disposed on the second face of the elongated substrate, the fourth group of trace elements electrically connected to a fourth group of electrodes of the plurality of electrodes; and control circuitry electrically connected to the plurality of electrodes via the plurality of trace elements and configured to control the plurality of electrodes to deliver energy to tissue of a patient, wherein the control circuitry is configured to activate the first group of electrodes and the second group of electrodes for a first time period, wherein the control circuitry is configured to activate the third group of electrodes and the fourth group of electrodes for a second time period different than the first time period, wherein, when activated by the control circuitry for the first time period, the first group of electrodes and the second group of electrodes have a different polarity, and wherein, when activated by the control circuitry for the second time period, the third group of electrodes and the fourth group of electrodes have a different polarity.

[0011] The details of one or more examples of the disclosure are set forth in the accompanying drawings and the description below. Other features, objects, and advantages of the disclosure will be apparent from the description and drawings, and from the claims.

BRIEF DESCRIPTION OF DRAWINGS

[0012] FIG. 1 A is partially conceptual diagram illustrating an example medical system to deliver cardiac ablation energy as well as to detect and/or sense signals.

[0013] FIG. IB is a side view of an example catheter from the example of FIG. 1 A.

[0014] FIG. 2A and FIG. 2B are conceptual diagrams illustrating examples of a flex circuit according to this disclosure. [0015] FIG. 2C is a conceptual diagram showing a cross-sectional view of the flex circuit of the examples of FIG. 2 A and FIG. 2B.

[0016] FIG. 3 A and FIG. 3B show an approximately isometric view and a side view, respectively, of an example connector configured to interface with a proximal portion of an ablation catheter and a flex circuit.

[0017] FIG. 4 is a conceptual diagram showing a cross-sectional view of a flex circuit according to some examples of this disclosure.

[0018] FIG. 5. is a conceptual diagram illustrating an example flex circuit according to this disclosure.

[0019] FIG. 6 is a flow diagram illustrating an example technique for introducing and advancing a medical system according to the techniques of this disclosure.

DETAILED DESCRIPTION

[0020] This disclosure describes devices, systems, and methods relating to medical device systems, including systems used during medical procedures such as ablation of tissue (e.g., cardiac tissue) to treat one or more patient conditions (e.g., arrythmias). In such medical procedures including cardiac ablation, energy can be delivered to one or more regions of tissue via devices (e.g., catheters) at discreate points (e.g., discreate locations). Energy can include radiofrequency (RF), pulsed field (PF), cryogenic therapy (e.g., cryoablation), microwave, laser, and/or combinations thereof configured to treat one or more patient conditions. The medical systems and devices described herein can include one or more catheters configured to be introduced into a patient and navigated to target tissue to perform a medical procedure (e.g., cardiac ablation).

[0021] In examples described herein, a medical system includes one or more catheters configured to be used in a medical procedure (e.g., a cardiac ablation procedure). At least one catheter is configured for delivering energy (e.g., ablation energy) to tissue of a patient, such as via one or more delivery elements (e.g., electrodes, transducers, structures configured to transmit energy, and the like). Throughout this disclosure, delivery elements are also be referred to as electrodes, although it is understood that delivery elements can include other delivery elements besides electrodes. In some examples, the medical system also includes one or more sensors configured to sense and/or receive information (e.g., signals, including bioelectric signals), such as from tissue of the patient. In some examples described herein, a catheter is configured for both sensing signals as well as for delivery of ablation energy. The medical system includes processing circuitry (e.g., also referred to herein as control circuitry) operably coupled to the sensors and/or delivery elements of the one or more catheters. The processing circuitry is configured to control energy delivery and/or receive information from the sensors. The medical system also includes energy generation circuitry operably coupled to the delivery elements. In some examples, the energy generation circuitry (e.g., along with the control circuitry) is configured to deliver energy via the delivery elements.

[0022] In some examples, a single catheter includes the one or more sensors and one or more delivery elements, however separate catheters each respectively having sensors and/or delivery elements can be used.

[0023] In some examples, one or more catheters include delivery elements where energy is delivered between delivery elements on the same catheter or between delivery elements on different catheter (e.g., electrodes of different polarity on two different catheters). In some examples, energy is delivered between delivery elements (e.g., electrodes) of one or more catheters and an external reference electrode and/or ground patch. The medical system includes processing circuitry operably coupled to the sensors and/or delivery elements of the catheter(s) configured to control energy delivery and/or receive information from the sensors.

[0024] In some examples, the medical system includes a positioning subsystem configured to track and record positions of one or more the catheter, the delivery elements, the sensors, and/or or other suitable components of the medical system.

[0025] Some catheters include wires, instead of and/or in addition to trace elements, for connecting components. However, as described in more detail, use of trace elements for at least some parts and/or components of the catheter, may potentially provide advantages.

[0026] In examples described herein, the catheter may include trace elements, such as where the processing circuitry and/or energy generation circuitry is connected to the sensors and/or delivery elements via the trace elements disposed on a flex circuit (e.g., instead of wires). Using trace elements and a flex circuit to connect the circuitry and the sensors and/or delivery elements may reduce or even eliminate a risk of unwanted electrical shorting (e.g., electrical connection) between certain portions of conductors of the trace elements. Particularly in applications with relatively high voltage values (e.g., equal to or greater than 1200 volts, such as 1500 volts and greater) and/or relatively high current, decreasing and/or eliminating a risk of unwanted electrical shorting can help ensure efficacious and uninterrupted therapy (e.g., ablation therapy) to a patient.

[0027] In some examples, using a flex circuit to connect the circuitry and the sensors and/or delivery elements can increase the mechanical robustness of the catheter (e.g., in response to various forces experienced by the catheter). Additionally, trace elements and a flex circuit provide a relatively small form factor, which may enable a reduced cross- sectional area of at least a portion of the catheter. A reduced cross-sectional area of the catheter may facilitate relatively easy introduction and/or navigation of the catheter to target tissue of the patient. Additionally or alternatively, a reduced cross-sectional area of the catheter may enable the use of additional system components (e.g., more conductors to supply more delivery elements such as electrodes, and/or more sensors), which might otherwise not be possible due to space constraints.

[0028] In some examples herein, the trace elements and corresponding electrodes are positioned and/or organized on the elongated substrate to reduce or even eliminate chances of unwanted electrical shorting between particular trace elements. For example, in some examples described herein, trace elements corresponding to electrodes having different polarity are disposed on opposite faces of the elongated substrate of the flex circuit. The elongated substrate can be sized, shaped, and/otherwise configured to electrically insulate respective groups of trace elements, such as to prevent unwanted electrical shorting (e.g., such as during period in which electrical energy is delivered to the electrodes via the electrical trace elements). In some examples, trace elements are additionally or alternatively grouped on lateral sides of the elongated substrate, such as grouped according to those trace elements and electrodes that are active during a given time period (e.g., a first time period and a second time period).

[0029] FIG. 1 A is a partially conceptual diagram illustrating an example medical system 100 according to the techniques of this disclosure. Medical system 100 includes a catheter 102 (e.g., an ablation catheter) and an interface unit 104. In some examples, medical system 100 also includes one or more anatomical information devices (e.g., that enable visualization of catheter 102 and/or tissue of patient 101). In some examples, medical system 100 is configured to deliver ablation energy, as well as map and/or record signals from a patient 101. In general, to deliver ablation energy, a user (e.g., clinician, electrophysiologist, interventional cardiologist, etc.) may insert catheter 102 into patient 101 and cause interface unit 104 to deliver, via catheter 102, energy (e.g., ablation energy) to target tissue of patient 101 (e.g., as part of a minimally-invasive therapy). In some examples, ablation therapy is delivered to multiple areas to create multiple lesions. For example, ablation energy may be delivered by interface unit 104 via catheter 102 to multiple overlapping lesions.

[0030] Ablation therapy (e.g., energy) may include one or more of pulsed field ablation (PF or PF A) energy, radiofrequency (RF) ablation energy, laser ablation, thermal ablation, cryoablation or cryogenic ablation, microwave energy, carbon ion beam ablation, cryoablation energy, ultrasound energy, another suitable energy or therapy modality, and/or a combination thereof. Ablation may cause lesions in target tissue (e.g., cardiac tissue) which may mitigate, stop, and/or prevent cardiac arrhythmias or other types of patient conditions.

[0031] In some examples, catheter 102 is configured to deliver ablation energy to tissue of patient 101. In some examples, catheter 102 includes one or more delivery elements 110 (shown individually as delivery element 110-1, delivery element 110-2, delivery element 110-3, delivery element 110-4, delivery element 110-5, delivery element 110-6, delivery element 110-7, delivery element 110-8, delivery element 110-9 and collectively referred to herein as delivery elements 110). Each of delivery elements 110 may include an electrode (e.g., in the case of a RF or PFA catheter), a cryogenic element (e.g., in the case of a cryoablation catheter), an ultrasound transducer (e.g., in the case of an ultrasound catheter), or another suitable delivery element. Throughout this disclosure, delivery elements 110 are also be referred to as electrodes 110, although it is understood that delivery elements 110 can include other delivery elements besides electrodes. In some examples, delivery elements 110 are disposed on, or carried by, an elongated body 112 of catheter 102. While the example of FIG. 1A and FIG. IB shows nine delivery elements 110, any suitable number of delivery elements 110 can be used (e.g., one, two, three, four, five, ten, twenty, etc.) in any suitable arrangement.

[0032] In one or more examples, as described in more detail below, delivery elements 110 can have a suitable configuration for delivery of ablation energy to tissue of patient 101. In some examples, delivery elements 110 can include bipolar electrodes, unipolar electrodes, other types of electrodes, and/or a suitable combination thereof. In some examples, delivery elements 110 and/or sensors include one or more neutral electrodes and/or one or more reference electrodes. In some examples, the one or more neutral electrodes are configured as a return path for current (e.g., in cases of unipolar energy delivery). In some examples, the one or more reference electrodes are configured for measuring and/or recording impedance, which may be useful for testing electrodes 110 and/or for use with the positioning subsystem. In some examples, one or more elements (e.g., one or more electrodes) can serve as both the neutral electrodes and reference electrodes. In other examples, the one or more neutral electrodes are unique and separate from (e.g., physically separate from) the one or more reference electrodes.

[0033] In some examples, one or more reference electrodes and/or neutral electrodes are positioned on a different portion of catheter 102 as compared to delivery elements 110. For example, the one or more reference electrodes and/or neutral electrodes can be positioned at (e.g., on) a distal portion of elongated body 112 (e.g., spaced apart from and proximal to all of delivery elements 110). In some examples, the one or more reference electrodes and/or neutral electrodes are positioned on a portion of catheter 102 that is configured to remain spaced apart from (e.g., not contact) cardiac tissue (e.g., not contact during ablation). In some examples, the one or more reference electrodes and/or neutral electrodes are positioned on a portion of catheter 102 that is configured to remain surrounded by blood (e.g., such that the one or more reference electrodes can measure blood impedance, which can be compared to impedance measurements by delivery elements 110, such as to determine a proximity of delivery elements 110 to cardiac tissue and/or to determine whether delivery elements 110 are in contact with cardiac tissue). Interface unit 104 can be configured to receive impedance measurements from the one or more reference electrodes and one or more delivery elements 110 and determine, based on the impedance measurements, a proximity and/or contact status of delivery elements 110 with respect to cardiac tissue.

[0034] In some examples, medical system 100 includes delivery elements 110 configured to have energy delivered between delivery elements 110 on the same catheter (e.g., catheter 102) or between delivery elements 110 on different catheters (e.g., catheter 102 and a second, different catheter). In some examples, ablation energy is delivered between delivery elements 110 (e.g., electrodes) of one or more of catheter 102 and an external reference electrode and/or ground patch (e.g., that may be applied to and/or positioned proximate to an external surface of patient 101).

[0035] Delivery elements 110 may be of any suitable geometry and/or configuration. In examples, where delivery elements 110 include one or more electrodes, geometries of electrodes include, but are not necessarily limited to, circular (e.g., ring) electrodes surrounding the body of catheter 102, conformable electrodes, cuff electrodes, segmented electrodes (e.g., electrodes disposed at different circumferential positions around catheter 102 instead of a continuous ring electrode), any combination thereof (e.g., ring electrodes and segmented electrodes).

[0036] Delivery elements 110 may be axially distributed along longitudinal axis of elongated body 112 or in several other configurations. In some examples, catheter 102 may include one or more delivery elements 110 positioned at different axial and radial positions relative to elongated body 112. In some examples, delivery elements 110 are disposed around an expandable structure 111, which may be expanded when performing cardiac ablation and compressed when navigating catheter 102 to target tissue. Delivery elements 110 may also be in a circular form, in an array, along multiple splines, or in other configurations.

[0037] In some examples, medical system 100 includes one or more sensors (not shown in the example of FIG. 1 A). The sensors (which may be the same as the delivery elements 110, such as electrodes, or different structures) may be used for detecting, sensing, and/or transmitting information about patient 101 and/or operating parameters of medical system 100. In some examples, delivery elements 110, which can include electrodes, are configured as sensors. In other examples, medical system 100 includes one or more sensors separate (e.g., physically separate from) delivery elements 110.

[0038] In some examples, interface unit 104 is configured to receive signals that indicate one or more measurable parameters associated with catheter 102 and/or energy delivered via catheter 102, including one or more of temperature, voltage, delivered current, and/or tissue contact. In some examples, interface unit 104 is configured to receive signals corresponding to one or more characteristics of tissue of patient 101, such as temperature of tissue of patient 101, electrogram (EGM) waveforms, monophasic action potentials, impedance (e.g., tissue impedance), or the like. The one or more sensors can be positioned on a portion of catheter 102, including elongated body 112 (which can include expandable structure 111). In some examples, interface unit 104, is configured to monitor, record, or otherwise receive measurements or conditions via the sensors of catheter 102, other components of medical system 100, and/or the ambient environment at the distal portion of the energy delivery device (e.g., from tissue of patient 101). The sensors may be in communication with interface unit 104 for initiating or triggering one or more alerts or ablation energy delivery modifications during operation of the energy delivery device. In some examples, the sensors may be part of interface unit 104, and/or anatomical information device(s).

[0039] Catheter 102 may generally include features that enable insertion of catheter 102 into patient 101, as well as navigation of catheter 102 to a target tissue site. In some examples, elongated body 112 includes a distal portion 106 configured to insertion into patient 101 as well as a proximal portion 108 (e.g., which can include a handle) configured to remain extracorporeal (e.g., outside) of patient 101. Proximal portion 108 may be configured to be positioned outside of the body of the patient while the distal portion 106 is positioned within the body the patient (e.g., during a period of cardiac ablation). Proximal portion 108 can be configured to be handled by a user (e.g., a clinician) to control distal portion 106. Delivery elements 110 may be positioned at distal portion 106 of elongated body 112, while a proximal portion 108 may be coupled (e.g., mechanically coupled and/or electrically coupled) to interface unit 104 (e.g., via a cable 113).

[0040] In some examples, catheter 102 includes an expandable structure 111 at distal portion 106 of catheter 102. Expandable structure 111 be configured to transform between a delivery (e.g., relatively low-profile) configuration and a deployed (e.g., expanded, including radially expanded) configuration. In some examples, expandable structure I l l is configured to position delivery elements 110 into contact with target tissue of patient 101, and/or into a position in which they are configured to be maneuvered into contact with target tissue. For example, in the deployed configuration, expandable structure 111 can be configured to expand radially outward relative to a longitudinal axis of elongated body 112 to position one or more delivery elements 110 into contact with tissue of patient 101. In some examples, delivery elements 110 are disposed on expandable structure 111. In some examples, one or more of delivery elements 110 includes an expandable structure (e.g., an expandable lattice structure formed from a conductive material). In some examples, expandable structure 111 additionally or alternatively includes one or more of a balloon, a basket, splines, other suitable expandable structure, and/or a combination thereof.

[0041] In some examples, electrodes 110 are disposed on expandable element 111 such that when expandable element 111 is in the deployed (e.g., expanded) configuration, electrodes 110 form an ordered, circumferentially spaced-apart sequence. For example, when expandable element 111 is in the deployed (e.g., expanded) configuration, electrodes

110 are disposed at respective spaced apart circumferential locations around expandable structure 111 such that electrode 110-1 is disposed at a first location, and successive electrodes 110 (e.g., electrode 110-2, electrode 110-3, electrode 110-4, electrode 110-5, electrode 110-6, electrode 110-7, electrode 110-8, electrode 110-9) form an ordered, clockwise or counter-clockwise sequence (e.g., around expandable structure 111, around a longitudinal axis of elongated body 112, etc.).

[0042] In some examples, expandable structure 111 includes an elongated structure that is configured to form a loop in the deployed configuration. The loop of expandable structure 111 can be configured to extend radially outward relative to elongated body 112 and position delivery elements 110 at different circumferential positions (e.g., relative to a central longitudinal axis of elongated body 112 and or catheter 102). The elongated structure that forms the loop of expandable structure 111 can also be configured to be straightened, such as when in the delivery configuration, such that expandable structure

111 has a relatively smaller cross-sectional profile in the delivery configuration.

[0043] In other examples, expandable structure I l l is configured to at least partially self-expand. For example, expandable structure 111 can include one or more materials (e.g., nitinol) that enable expandable structure 111 to self-expand. In some examples, expandable structure I l l is configured to have a bias toward a deployed (e.g., expanded) configuration. In some examples, expandable structure 111 is manually activated (e.g., via pullwire, inflation, or another suitable expansion mechanism).

[0044] As shown in the example of FIG. 1 A and FIG. IB, at least a portion of expandable structure I l l is mechanically coupled to a second elongated body 114. The second elongated body can be at least partially disposed within elongated body 112, which may be a first elongated body. In some examples, relative axial movement of elongated body 112 and second elongated body 114 causes expandable structure to transform between the delivery (e.g., compressed) configuration and the deployed (e.g., radially expanded) configuration.

[0045] In some examples, interface unit 104 may include a generator (e.g., including cardiac ablation energy generation circuitry) configured to provide energy (e.g., electrical energy, cryogenic therapy, or another suitable form of therapy) to delivery elements 110 to perform an ablation procedure to tissue of patient 101. In some examples, the tissue to which energy is applied includes cardiac tissue, such as tissue proximate the pulmonary vein, or tissue within a chamber of the heart. While the examples discussed in this disclosure are primarily in the context of cardiac tissue, the tissue of patient 101 to which energy is applied can include any suitable tissue within the patient’s body, such as renal tissue, airway tissue, and other organs. For instance, in some examples, the generator (e.g., energy generator) of interface unit 104 is configured and programmed to deliver pulsed, high-voltage electric fields appropriate for achieving desired pulsed, high-voltage ablation (e.g., “pulsed field ablation” or “pulsed electric field ablation”) and/or pulsed or nonpulsed radiofrequency ablation. In some examples, the generator (e.g., energy generator), along with control circuitry of interface unit 104 is configured to deliver energy between at least some of the plurality of electrodes 110 at a voltage of at least 1200 volts (e.g., such as 1500 volts to 4000 volts). In some examples, the energy generator is configured and programmed for achieving desired cryogenic ablation. In some examples, the energy generator is configured as an acoustic generator and programmed to deliver ultrasound energy, such as for achieving ultrasound ablation.

[0046] In some examples, the generator of interface unit 104 is configured to control (e.g., activate) one or more subsets of delivery elements 110 (e.g., which may include electrodes) during one or more periods (e.g., succussive time intervals) of energy delivery. For example, in some examples, the generator of interface unit 104 is configured to deliver ablation energy by activating different groups of delivery elements 110 during separate and/or successive time periods. Activating a group of delivery elements 110 may refer to delivering an electrical signal to the group of delivery elements 110 so that the group of delivery elements 110 form anodes or cathodes to allow the flow of electrical energy. For instance, delivery elements 110 may be electrodes in a non-charged state when not activated. However, when electrical signals are delivered to the group of delivery elements 110, there is a charge imbalance on the group of delivery elements 110. The existence of this charge imbalance on a group of delivery elements 110 may be considered as activating the group of delivery elements 110.

[0047] In some examples, the generator of interface unit 104 is configured to activate (e.g., energize, such as by delivering an electrical signals to) at least a first group of delivery elements 110 and a second group of delivery elements 110 for a first time period (e.g., while a third group of delivery elements 110 and a fourth group of delivery elements 110 are inactive and/or not energized, such that the third group of delivery elements 110 and the fourth group of delivery elements 110 do not receive electrical signals from interface unit 104). In some examples, the generator of interface unit 104 is configured to activate at least the third group of delivery elements 110 and the fourth group of delivery elements 110 for the second time period that is different from the first time period (e.g., while the first group of delivery elements 110 and the second group of delivery elements 110 are inactive).

[0048] In the aforementioned example, the first and second groups of delivery elements 110 can have a different polarity from each other such that current is driven (e.g., by interface unit 104) between the first and second groups of delivery elements 110 during the first time period. Similarly, the third and fourths groups of delivery elements 110 can have a different polarity from each other such that current is driven (e.g., by interface unit 104) between the third and fourth groups of delivery elements 110 during the second time period. Delivery elements 110 having a different polarity can mean that the trace elements, described in more detail herein, coupled to delivery elements 110 are provided with a different voltage, hence the voltage on different groups of delivery elements 110 may be different. A first polarity can refer to a relative higher voltage and a second polarity can refer to a relatively lower voltage, or vice versa, such that current flows from the delivery elements 110 with relatively higher voltage to delivery elements 110 with the relatively lower voltage. A voltage difference can be created between delivery elements 110 having different polarities (e.g., different relative voltage level values), such that current flows between delivery elements 110 having different polarity.

[0049] In examples herein, any of delivery elements 110, which can include electrodes, can be selected as a cathode and/or an anode, such that at least some of delivery elements 110 can be considered cathodes and other delivery elements 110 can be considered anodes. Electrical fields can be generated by flow between one or more anodes and one or more cathodes.

[0050] In some examples, generator of interface unit 104 is configured to alternate activation of the groups of delivery elements 110 to deliver successive periods (e.g., bursts) of ablation energy over an overall time period of delivery of ablation. Any number of groups of delivery elements 110 and/or numbers of succussive time periods (e.g., like the first time period and the second time period) can be used to deliver ablation energy. In some examples, interface unit 104 is configured to deliver bipolar ablation energy during the first time period and/or the second time period.

[0051] As an illustrative example, and with reference to FIG. 1 A and FIG. IB, interface unit 104 is configured to deliver bipolar energy between a first group of delivery elements 110 (e.g., delivery element 110-1, delivery element 110-5, and delivery element 110-9) and a second group of delivery elements 110 (e.g., delivery element 110-3 and delivery element 110-7) during a first time period. The first time period may be about 50 milliseconds to about 1 second. The first group of electrodes 110 (e.g., electrode 110-1, electrode 110-5, and electrode 110-9) and the second group of electrodes 110 (e.g., electrode 110-3 and electrode 110-7) can be considered the “odd” electrodes according the ordered sequence of electrodes 110 shown in the example of FIG. 1 A and FIG. IB, with electrode 110-1 being a starting electrode, and each of electrode 110-2, electrode 110-3, electrode 110-4, electrode 110-5, electrode 110-6, electrode 110-7, electrode 110-8, and electrode 110-9 following in an ordered sequence around and/or along expandable element 111 (e.g., such as counterclockwise around expandable element 111 in the example of FIG. 1 A). In some examples, each of the first group of electrodes 110 (e.g., electrode 110- 1, electrode 110-5, and electrode 110-9) has a first polarity (e.g., a relatively higher voltage), and each of the second group of electrodes 110 (e.g., electrode 110-3 and electrode 110-7) has a second polarity (e.g., a relative lower voltage, such as compared to the first polarity) different from the first polarity, such that bipolar energy is delivered between the first group of electrodes 110 and the second group of electrodes 110 for the first time period. As described above, a first polarity can refer to a relative higher voltage and a second polarity can refer to a relatively lower voltage, or vice versa, such that current flows from the delivery elements 110 with relatively higher voltage to delivery element 110 with the relatively lower voltage. A voltage difference can be created between delivery elements 110 having different polarities (e.g., different relative voltage level values), such that current flows between delivery elements 110 having different polarity.

[0052] While the terms “first polarity” and “second polarity” are used in the examples discussed throughout this disclosure, it should be understood that such terms are used to describe relative polarities of active electrodes 110, and are not necessarily used to describe specific polarities of electrodes 110 (e.g., positive polarity, negative polarity, another polarity, etc.). For example, it is understood the term “first polarity” can either be a positive polarity, a negative polarity, another polarity, and/or an alternating polarity, such that it is a different polarity from a “second polarity.” Additionally or alternatively, the first polarity and the second polarity can change (e.g., from positive polarity to negative polarity), such as within a given time period of energy delivery. However it is understood that the first polarity would be different than the second polarity at any given time within the given period of energy delivery.

[0053] Continuing with the aforementioned example, during delivery of energy between the first group of electrodes 110 (e.g., electrode 110-1, electrode 110-5, and electrode 110-9) and the second group of electrodes 110 (e.g., electrode 110-3 and electrode 110-7) for the first time period, a third group of electrodes 110 (e.g., electrode 110-2 and electrode 110-6) and a fourth group of electrodes 110 (e.g., electrode 110-4 and electrode 110-8) are inactive (e.g., not energized by interface unit 104).

[0054] Continuing with the aforementioned example, and with reference to FIG. 1 A and FIG. IB, interface unit 104 is configured to deliver bipolar energy between the third group of electrodes 110 (e.g., electrode 110-2 and electrode 110-6) and the fourth group of electrodes 110 (e.g., electrode 110-4 and electrode 110-8) during a second time period. The second time period may be about 50 milliseconds to about 1 second. In some examples, the second period is after and non-overlapping with the first time period. In some examples, the first and second time periods are time separated (e.g., separated by a finite period of time in which none of electrodes 110 active and/or energized). The third group of electrodes 110 (e.g., electrode 110-2 and electrode 110-6) and the fourth group of electrodes 110 (e.g., electrode 110-4 and electrode 110-8) can be considered the “even” electrodes according to the ordered sequence of electrodes 110 shown in the example of FIG. 1 A and FIG. IB. In some examples, each of the third group of electrodes 110 (e.g., electrode 110-2 and electrode 110-6) has a first polarity (e.g., a negative polarity), and each of the fourth group of electrodes 110 (e.g., electrode 110-4 and electrode 110-8) has a second polarity (e.g., a positive polarity) different from the first polarity, such that bipolar energy is delivered between the third group of electrodes 110 and the fourth group of electrodes 110 for the second time period.

[0055] In some examples, during delivery of energy between the third group of electrodes 110 (e.g., electrode 110-2 and electrode 110-6) and the fourth group of electrodes 110 (e.g., electrode 110-4 and electrode 110-8) for the second time period, the first group of electrodes 110 (e.g., electrode 110-1, electrode 110-5, and electrode 110-9) and the second group of electrodes 110 (e.g., electrode 110-3 and electrode 110-7) are inactive (e.g., not energized by interface unit 104).

[0056] In some examples, interface unit 104 is configured to selectively energize each of the first group of electrodes 110, the second group of electrodes 110, the third group of electrodes 110, and the fourth group of electrodes 110 in successive time periods (e.g., like the first time period and the second time period) over an overall time period of energy delivery, such as to deliver pulsed, high-voltage electric fields appropriate for achieving desired pulsed, high-voltage ablation (e.g., “pulsed field ablation” or “pulsed electric field ablation”).

[0057] While the aforementioned examples are discussed in terms of bipolar delivery elements (e.g., electrodes), it should be recognized that delivery elements 110 can include other configurations (e.g., monopolar, unipolar, etc.), and that any number of groups of delivery elements 110 in any ordered and/or unordered combination can be activated during any number of time periods during delivery of ablation energy via interface unit 104. For example, in some examples, all electrodes 110 can be activated during a period of energy delivery, such as in a configuration where all “odd” electrodes (e.g., electrode 110- 1, electrode 110-3, electrode 110-5, electrode 110-7, and electrode 110-9) are configured to have a first polarity and all “even” electrodes (e.g., electrode 110-2, electrode 110-4, electrode 110-6, and electrode 110-8) are configured to have a second polarity, such that energy is delivered between the odd electrodes and the even electrodes. Examples in which all electrodes 110 are active may include examples with relatively lower voltage (e.g., around 1000 volts, such up to 1200 volts), where there is relatively lower risk of shorting given the relatively lower voltage. [0058] In some examples, interface unit 104 may include circuitry configured to execute one or more functions related to energy delivery (e.g., via delivery elements 110), sensing patient parameters (e.g., via sensors of catheter 102 and/or another device), and/or other functions related to the determination (e.g., calculation) of relevant indices, parameters, and other information related to a medical procedure. In some examples, interface unit 104 includes a generator, which may be an energy generator, configured to control delivery elements (e.g., delivery elements 110 of catheter 102) such as to provide electrical energy to electrodes (e.g., delivery elements 110) to perform an ablation procedure to cardiac tissue or other tissues within the patient’s body, including but not limited to renal tissue, airway tissue, bones, organs, or tissue within the cardiac space or the pericardial space.

[0059] For instance, in some examples, generator is configured and programmed to deliver pulsed, high-voltage electric fields appropriate for achieving desired pulsed, high- voltage ablation (referred to as “pulsed field ablation” or “pulsed electric field ablation”) and/or pulsed radiofrequency ablation. In another example, the generator of interface unit 104 is configured to control one or more cryogenic energy delivery elements to achieve desired cryogenic ablation. In some examples, energy generator includes multiple energy generators that are each capable of generating ablation signals in parallel. In some examples, interface unit 104 includes energy generators of different types, such as a pulsed field energy generator, a radiofrequency energy generator, and/or a cryogenic energy generator.

[0060] In some examples, processing circuitry of interface unit 104 is configured to control the generator to deliver ablation energy according to one or more ablation parameters. Ablation parameters may include a combination of delivery elements (e.g., a subset of delivery elements 110) to the target tissue, a suggested positioning for one or more delivery elements 110, a suggested energy level to be delivered, an energy modality (e.g., RF, cryogenic, PF A, etc.) or combination of modalities, or the like.

[0061] Processing circuitry of interface unit 104 may include one or more processors, such as any one or more of a microprocessor, a controller, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field-programmable gate array (FPGA), discrete logic circuitry, or any other processing circuitry configured to provide the functions attributed to interface unit 104 herein, which may be embodied as firmware, hardware, software or any combination thereof.

[0062] In some examples, interface unit 104 includes a memory and/or storage device, which may include a computer-readable storage medium or computer-readable storage device. In some examples, the memory and/or storage device includes one or more of a short-term memory or a long-term memory. The storage device may include, for example, random-access memories (RAM), dynamic random-access memories (DRAM), static random-access memories (SRAM), ferroelectric random-access memories (FRAM), magnetic discs, optical discs, flash memories, or forms of electrically programmable memories (EPROM) or electrically erasable and programmable memories (EEPROM). In some examples, the memory and/or storage device is used to store data indicative of instructions, e.g., for execution by processing circuitry of interface unit 104.

[0063] In some examples, interface unit 104 includes a positioning subsystem configured to track and record positions of one or more of catheter 102, delivery elements 110, sensors, or other suitable components of medical system 100. In some examples, the positioning subsystem is configured to track one or more of catheter 102, delivery elements 110, and/or sensors via an electromagnetic signal, injected current signals, fluoroscopy, or the like. In some examples, interface unit 104 includes one or more of an electromagnetic signal and/or electromagnetic field generator, a generator to inject current, and/or another generator for tracking a position of one or more of catheter 102, delivery elements 110, and/or sensors. In some examples, one or more portions of catheter 102, delivery elements 110, and/or sensors are radiopaque and may be tracked via a suitable imaging modality. In some examples, sensors include accelerometers or other sensors (e.g., position sensors, such as electromagnetic coils) configured to facilitate tracking of relative movement of sensors or movement relative to a reference position. In some examples, sensors include force sensors, which may be configured to sense force (e.g., contact force) and/or pressure between at least a portion of catheter 102 and tissue (e.g., cardiac tissue) of patient 101.

[0064] In some examples, one or more sensors of the catheter 102 (e.g., at distal portion 106) include position sensors for enabling interface unit 104 to track the position, as well as a shape and/or an orientation, of catheter 102 (e.g., including distal portion 106, delivery elements 110, and/or sensors). In some examples, one or more position sensors of catheter 102 include sensors configured to detect one or more signals or one or more fields, such as (but not limited to) electromagnetic signals, electromagnetic fields, magnetic fields, or another suitable position tracking signal or field. For example, an electromagnetic position sensor may include one or more induction coils that induce a current to detect signals emanating from electromagnetic field generators. One or more coils for determining position with five or six degrees of freedom can be used.

[0065] The magnetic field detected by the electromagnetic position sensor may be used to determine the location (e.g., position, orientation, and/or shape) of a portion of catheter 102, such as distal portion 106 according to one or more methods commonly known in the art such as, for example, methods based on using a magnetic sensor to sense magnetic fields and using a look-up table to determine location of the magnetic position sensor. Accordingly, because other portions of catheter 102, including elongated body 112, delivery elements 110 and/or other sensors may have a fixed relationship to the magnetic position sensor, the magnetic position sensor may also provide the location (e.g., position, orientation, and/or shape) these other portions of catheter 102. Other position sensing methods can additionally or alternatively be used. For example, the location (e.g., position, orientation, and/or shape) one or more portions of catheter 102 can be additionally, or alternatively, be tracked based on impedance, ultrasound, and/or imaging (e.g., real time magnetic resonance imaging (MRI) or fluoroscopy).

[0066] In some examples, interface unit 104 includes a user interface 105. In some examples, user interface 105 includes a screen, display, and/or another visual output medium (e.g., augmented reality display or virtual reality display). In some examples, user interface 105 includes a button or keypad, lights, a speaker for voice commands, and the display can include one or more of a liquid crystal (LCD), light-emitting diode (LED), or organic light-emitting diode (OLED) display.

[0067] In some examples, interface unit 104 is configured to generate and present (e.g., display), via user interface 105, information about one or more of patient 101, tissue of patient 101, catheter 102, energy delivered to the tissue via delivery elements 110, and/or signals sensed by sensors. In some examples, interface unit 104 is configured to generate and present (e.g., display), via user interface 105, a representation of tissue of patient 101. The representation of tissue can include a portion of an organ (e.g., a heart) of patient 101. For example, the representation of tissue can include a “shell” representing the boundary of an organ (e.g., the heart of patient 101). In some examples, interface unit 104 is configured to generate and present (e.g., display), via user interface 105, a representation of catheter 102, delivery elements 110, and/or sensors. The representation of catheter 102, delivery elements 110, and/or sensors may enable a user (e.g., a clinician) to determine a spatial relationship between tissue of patient 101 and catheter 102 (e.g., one or more of distal portion 106, delivery elements 110, and/or sensors). For example, interface unit 104 may enable a user (e.g., a clinician) to know which portion of tissue is in contact with catheter 102, which may indicate where energy will be delivered during a period of energy delivery via delivery elements 110. In some examples, interface unit 104 may enable a user (e.g., a clinician) to know a distance between one or more portions of catheter 102 and tissue (e.g., in examples where one or more portions of catheter 102 is not touching a portion of tissue).

[0068] In some examples, interface unit 104 includes one or more anatomical information device(s) configured to enable visualization of portions of tissue of patient 101. Anatomical information device(s) can additionally or alternatively enable virtualization of one or more portions of catheter 102. In some examples, anatomical information device(s) include one or more of a computed tomography (CT) device, a magnetic resonance imaging (MRI) device, an ultrasound (U/S) device, a pacing device, an electrophysiology (EP) mapping device, and/or a non-invasive mapping device. Anatomical information device(s) may be used by medical system 100 to inform interface unit 104 of the anatomy of a patient, as well as physical and/or electrical characteristics of the anatomy, and/or a location of catheter 102 during delivery of catheter 102 into the anatomy of a patient. In some examples, interface unit 104 may include one or more of anatomical information device(s). In some examples, anatomical information device(s) provide or otherwise enable interface unit 104 to generate a representation of tissue of patient 101. In some examples, interface unit 104 is configured to receive anatomical information from anatomical information device(s) and generate, based on the anatomical information, the representation of tissue of patient 101.

[0069] In some examples, interface unit 104, which may be configured for ablating target tissue (e.g., a target tissue area or volume) of a patient 101, includes memory configured to store at least one of anatomical information of a patient or physiological information (e.g., temperature and/or cardiac electrophysiological information) of patient 101.

[0070] In some examples, interface unit 104 and/or catheter 102 are configured to deliver ablation energy to multiple locations over multiple instances of ablation (e.g., multiple periods of continuous application of ablation). In some examples, each instance of energy delivery is defined by the period of continuous application of ablation. In some examples, a user (e.g., a clinician) initiates each instance of energy delivery via a control (e.g., button) on one or more of catheter 102 and/or interface unit 104. For example, proximal portion 108 of catheter 102, which can include a handle, can be configured to receive input from a user (e.g., a clinician) to cause interface unit 104 to deliver ablation energy via delivery elements 110.

[0071] In some examples, processing circuitry of interface unit 104 is configured to receive one or more signals (e.g., from sensors of catheter 102) during application of ablation energy to tissue. The signals that interface unit 104 receives may include signals that indicate one or more of location and/or level (e.g., efficacy), as well as other parameters about delivered energy (e.g., otherwise referred to herein as “sensed therapy parameters”). In some examples, the signals (e.g., from delivery elements 110 and/or sensors) may indicate a location of catheter 102 (e.g., a location relative to tissue of patient 101 or an absolute location in three-dimensional space). For example, as discussed throughout this disclosure, interface unit 104 may include a positioning subsystem configured to, in conjunction with elements of catheter 102, provide signals that indicate a position of catheter 102.

[0072] Other signals used by (e.g., received by) interface unit 104 include signals that indicate a level and/or effectiveness of delivered energy and/or indicate a patient status or patient condition. In some examples, the signals indicate one or more of a temperature, electrogram (EGM), intracardiac signals including intracardiac electrograms (iEGMs), which may include bipolar and/or unipolar iEGMs, a current, a power, impedance, a contact force, and/or another measurable parameter (e.g. tissue viability). For example, in some examples, processing circuitry of interface unit 104 is configured to receive information indicating tissue contact (e.g., impedance signals) by distal portion 106 of catheter 102. As another example, in some examples processing circuitry of interface unit 104 is configured to receive information of temperature (e.g., a rise in temperature reflecting energy delivery) from sensors of catheter 102. In some examples, processing circuitry of interface unit 104 is configured to receive information (e.g., from an energy generator and/or positioning subsystem of interface unit 104) that indicates energy delivery to tissue of patient 101.

[0073] In examples described herein, as shown in the example of FIG. IB, catheter 102 includes a flex circuit 140 extending between at least proximal portion 108 (e.g., which can include a handle) and distal portion 106 of catheter 102. Flex circuit 140 can enable connection (e.g., communicative connection, electrical connection, or the like) between interface unit 104 and elements and/or portions of catheter 102 (e.g., delivery elements 110, sensors, other suitable elements, or combinations thereof). As discussed in connection with later examples, in some examples, flex circuit 140 is configured to carry electrical signals between interface unit 104 and delivery elements 110 (e.g., both from interface unit 104 to delivery elements 110 and from delivery elements 110 to interface unit 104). Additionally or alternatively, flex circuit 140 can be configured to carry electrical signals between interface unit 104 and one or more sensors (not shown in the examples of FIG. 1A and FIG. IB) on catheter 102 (e.g., both from interface unit 104 to the sensors and from the sensors to interface unit 104). In this way, flex circuit 140 can enable interface unit 104 (which may include a generator and/or energy generation circuitry) to deliver ablation energy to patient 101 via delivery elements 110, as flex circuit 140 can facilitate an electrical connection between interface unit 104 and delivery elements 110.

[0074] In some examples, as shown in the example of FIG. IB, catheter 102 includes a connector 116, which can be configured to facilitate coupling (e.g., mechanical coupling and/or electronical coupling) between flex circuit 140 and interface unit 104. For example, as discussed in connection with FIG. 3 A and FIG. 3B, connector 116 can include mating features to facilitate coupling (e.g., mechanical coupling and /or electronical coupling) between flex circuit 140 and cable 113, where cable 113 is configured to couple to interface unit 104. The mating features of connector 116 (e.g., that mate with either or both of portions of cable 113 and/or flex circuit 140) can enable a relatively faster, easier, and/or more reliable coupling (e.g., mechanical coupling and/or electrical coupling) between catheter 102 and interface unit 104. [0075] In some examples, connector 116 is configured to interface (e.g., mechanically interface and/or electrically interface) with at least another part of proximal portion 108 (e.g., the handle portion) of catheter 102. In some examples, connector 116 is configured to fit into a proximal portion of the handle of catheter 102. In some examples, connector 116 is configured to reversibly connect and/or disconnect from the handle, such as to connect interface unit 104 to catheter 102. In some examples, connector 116 is configured to reversibly connect and/or disconnect from cable 113 and/or another intermediate component to ultimately facilitate electrical connection with interface unit 104. In this way, connector 116 can facilitate a relatively easy and/or simple way to connect and/or disconnect catheter 102 from interface unit 104, which may enable a user (e.g., a clinician) to quickly connect different ones of catheter 102 to interface unit 104.

[0076] In some examples, flex circuit 140 includes a suitable configuration for carrying electrical signals between proximal portion 108 (e.g., which may include a handle) and distal portion 106 of catheter 102. In some examples, flex circuit 140 extends (e.g., in a continuous manner) between a proximal end of catheter 102 (e.g., a proximal end of proximal portion 108, which may include connector 116) and at least a distal -most one of delivery elements 110 (e.g., delivery element 110-9, as shown in the example of FIG. IB). This continuous extension of flex circuit 140 between proximal portion 108 (e.g., which may include a handle) and distal portion 106 of catheter 102 can reduce risks of electrical discontinuity (e.g., as compared to other configurations, including conductive wires), as flex circuit 140 can be configured to have relatively robust mechanical properties and better resist mechanical fatigue as compared to other possible means of electrically connecting interface unit 104 to delivery elements 110.

[0077] In some examples, flex circuit 140 is disposed in a lumen defined by catheter 102 (e.g., a lumen defined by one or more of proximal portion 108, elongated body 112, and/or expandable structure 111). Flex circuit 140 can define a relatively small cross- sectional area (e.g., as compared to other means of electrical connection, including conductive wires), such that flex circuit 140 takes up a relatively small amount of space when positioned the lumen defined by defined catheter 102. This relatively small cross- sectional area may enable other mechanical structures to be used in conjunction with catheter 102 (e.g., guidewires that extend through a lumen of catheter 102) and/or enable use of more delivery elements 110 (e.g., because relatively more conductive trace elements can be used with flex circuit 140 due to the relatively smaller cross-sectional area).

[0078] While the example of FIG. 1A and FIG. IB is primarily discussed in the context of a single catheter 102 configured for both energy delivery and sensing, the techniques of this disclosure may include using two or more separate catheters, e.g., a catheter to deliver ablation energy and a separate diagnostic catheter. For example, a first catheter (e.g., a mapping or diagnostic catheter), can be inserted into patient 101 to detect and measure information (e.g., temperature, EGM data) about tissue of patient 101. A second catheter (e.g., catheter 102) can be inserted into patient 101 to perform an ablation procedure, e.g., to target tissue identified by the first catheter. Additionally or alternatively, while the example of FIG. 1A and FIG. IB shows all of delivery elements 110 on a single catheter 102, some of delivery elements 110 can be disposed and/or carried by another catheter (e.g., like catheter 102) or another suitable structure. For example, a second, different catheter (e.g., like catheter 102) can be inserted into patient 101 (e.g., into a heart of patient 101, outside of heart of patient 101, or at another suitable location), such that energy is delivered by and/or between delivery elements 110 disposed on and/or carried by each of the first catheter 102 and the second catheter. In some examples, medical system 100 additionally or alternatively includes one or more external reference electrodes and/or ground patches, e.g., such that energy is delivered between delivery elements 110 of one or more of catheter 102 and the one or more external reference electrode and/or one or more ground patches.

[0079] While medical system 100 is described as having a separate catheter 102 and interface unit 104, with interface unit 104 including circuitry for delivering energy, sensing signals from patient 101, and/or performing other functions, it is understood that catheter 102 can additionally or alternatively include circuitry configured to execute one or more functions attributed to interface unit 104. For example, catheter 102 can include control circuitry configured to activate one or more of delivery elements 110 (e.g., cause delivery elements to deliver electrical signals to patient 101). In some examples, medical system 100 can include one or more of catheter 102, interface unit 104, the circuitry attributed to interface unit 104, components of each of catheter 102 or interface unit 104, and/or suitable combinations thereof. [0080] FIG. 2A and FIG. 2B are conceptual diagrams illustrating an example flex circuit 240. Flex circuit 240 may be an example of flex circuit 140 described above in connection with FIG. IB. Flex circuit 240 may have the same or similar characteristics and functionality as described above for flex circuit 140. Some components of FIG. 1A and FIG. IB will be referenced herein to demonstrate the functionality, physical orientation, and/or configuration of components of FIG. 2A and FIG. 2B.

[0081] FIG. 2C illustrates a cross-sectional view of flex circuit 240 from the example of FIG. 2 A and FIG. 2B, the cross section taken according to the A- A section label in the example of FIG. 2A (e.g., a cross-section parallel to the y-z plane and facing in the negative x-direction according to the orthogonal x-y-z axis in the example of FIG. 2A). [0082] As shown in the example of FIG. 2A and FIG. 2B, flex circuit 240 includes a plurality of trace elements 242 (shown individually as trace element 242-1, trace element 242-2, trace element 242-3, trace element 242-4, trace element 242-5, trace element 242-6, trace element 242-7, trace element 242-8, and trace element 242-9 but collectively referred to herein as trace elements 242). In some examples, trace elements 242 are disposed on a flexible elongated substrate 246 such that trace elements 242 extend between a proximal portion (e.g., which may include a proximal end) and a distal portion (e.g., which may include a distal end) of elongated substrate 246. Trace elements 242 can be formed of a suitable conductive material and configured to carry electrical signals. As shown in the example of FIG. 2A and FIG. 2B, trace elements 242 extend (e.g., continuously extend) between a proximal portion of flex circuit 240 and a distal portion of flex circuit 240.

[0083] In some examples, flex circuit 240 includes elongated substrate 246, which is configured to have plurality of trace elements 242 disposed on elongated substrate 246. Elongated substrate 246 can be relatively flexible, and configurated to accommodate movement and/or deformation of one or more portions of catheter 102 (e.g., proximal portion 108, elongated body 112, and or expandable structure 111, as discussed in the example of FIG. 1 A and FIG. IB).

[0084] In some examples, elongated substrate 246 includes a non-conductive material (e.g., an electrically insulative material), such as a polymer. In other examples, elongated substrate 246 includes a semi-conductive material that is less electrically conductive than a material of trace elements 242. As shown in the example of FIG. 2A and FIG. 2B, elongated substrate 246 defines least a first face 241 A and a second face 241B, with at least some of trace elements 242 disposed on each of first face 241 A and second face 241B. As shown, first face 241 A extends between a proximal portion and a distal portion of elongated substrate 246 in a direction parallel to the x-axis according to the orthogonal x-y-z axes shown in the example of FIG. 2 A. Second face extends between the proximal portion and the distal portion of elongated substrate 246 in a direction parallel to the x-axis according to the orthogonal x-y-z axes shown in the example of FIG. 2B. As shown, second face 241B is opposite first face 241 A (e.g., second face 241B faces in an opposite direction as first face 241 A). As shown in the example of FIG. 2C, first face 241 A faces in the positive y-axis direction and second face 24 IB faces in the negative y-axis direction according to the orthogonal x-y-z axes in FIG. 2C. The configuration of some of trace elements 242 being on opposite faces (e.g., each of first face 241 A and second face 241B) of elongated substrate 246 can reduce of risk of electrical shorting between those trace elements 242 disposed on the opposite faces.

[0085] In some examples, such as the example of FIG. 2C, flex circuit 240 additionally includes an upper substrate 247A and a lower substrate 247B. Upper substrate 247A and a lower substrate 247B can be configured to electrically insulate trace elements 242 (e.g., from media surrounding trace elements 242). In some examples, trace elements 242 disposed on first face 241A of elongated substrate 246 (e.g., trace element 242-1, trace element 242-2, trace element 242-5, trace element 242-6, and trace element 242-9) are positioned between elongated substrate 246 and upper substrate 247A. In some examples, trace elements disposed on second face 24 IB of elongated substrate 246 (e.g., trace element 242-3, trace element 242-4, trace element 242-7, and trace element 242-8) are positioned between elongated substrate 246 and lower substrate 247B. While the example of FIG. 2C shows elongated substrate 246 as a substrate layer between two additional substrate layers (e.g., upper substrate 247A and lower substrate 247B), flex circuit 240 can include additional substrate layers, such as to facilitate crossing of particular traces to enable connection to respective electrodes at a distal portion of flex circuit 240. In some examples, flex circuit 240 include more substrate layers (e.g., separate from elongated substrate 246) along the axial length of flex circuit 240 (e.g., to facilitate additional trace elements 242 and/or to provide further electrical insulation between one or more of trace elements 242) [0086] In the example of FIG. 2 A and FIG. 2B, flex circuit 240 includes a plurality of electrode pads 210 (shown individually as electrode pad 210-1, electrode pad 210-2, electrode pad 210-3, electrode pad 210-4, electrode pad 210-5, electrode pad 210-6, electrode pad 210-7, electrode pad 210-8, and electrode pad 210-9 but collectively referred to herein as electrode pads 210). Electrode pads 210 can be formed of a suitable conductive material and configured to carry and/or transmit electrical signals. One or more of electrode pads 210 can examples of delivery elements 110 from the example of FIG. 1 A and FIG. IB. Additionally or alternatively, electrodes pads 210 can be further connected to one or more electrodes (e.g., ring electrodes, like the example of FIG. 1 A and FIG. IB). In either instance, it is understood that electrical energy can be carried, transmitted, and/or delivered via electrode pads 210. In some examples, a generator (e.g., of interface unit 104 in the example of FIG. 1A) is configured to deliver ablation energy (e.g., RF, PF A, etc.) to delivery elements (e.g., electrodes 110 in the example of FIG. 1 A and FIG. IB) via electrode pads 210.

[0087] In the example of FIG. 2 A and FIG. 2B, each of plurality of electrode pads 210 is electrically connected to a respective trace element of trace elements 242 (e.g., electrode pad 210-1 is electrically connected to trace element 242-1, electrode pad 210-2 is electrically connected to trace element 242-2, electrode pad 210-3 is electrically connected to trace element 242-3, electrode pad 210-4 is electrically connected to trace element 242- 4, electrode pad 210-5 is electrically connected to trace element 242-5, electrode pad 210- 6 is electrically connected to trace element 242-6, electrode pad 210-7 is electrically connected to trace element 242-7, electrode pad 210-8 is electrically connected to trace element 242-8, and electrode pad 210-9 is electrically connected to trace element 242-9). Such connection to individual trace elements 242 enables circuitry (e.g., of interface unit 104 from the example of FIG. 4) to individually control (e.g., activate) respective electrodes associated with each of electrode pads 210. In other examples, multiple of electrode pads 210 can be connected to a common trace element of trace elements 242 (e.g., such that each of the multiple electrodes associated with multiple electrode pads 210 can be controlled together).

[0088] In the example of FIG. 2 A and FIG. 2B, each of plurality of electrode pads 210 is positioned at a distal portion of catheter 102 (e.g., as discussed with respect to FIG. 1 A and FIG. IB) and are configured to enable delivery of ablation energy to tissue (e.g., cardiac tissue) of patient 101. While electrode pads 210 are shown in conjunction with flex circuit 240 in the example of FIG. 2 A and FIG. 2B, electrode pads 210 can be physically separate from, but operatively connected (e.g., electrically connected) to flex circuit 240 (e.g., electrode pads 210 can be electrically connected to trace elements 242). In other examples, at least a portion of electrode pads 210 can be coupled to (e.g., mechanically and/or electrically coupled) and/or defined by at least a portion of flex circuit 240. For example, some of electrode pads 210 can be mechanically coupled to a portion of flex circuit 240 (e.g., including mechanically connected to elongated substrate 246). As another example, electrode pads 210 can be electrically connected to and/or defined by at least a portion of trace elements 242.

[0089] As discussed in relation to delivery elements 110 of FIG. 1 A and FIG. IB, electrode pads 210 (e.g., including subsets or groups thereof) can be selectively activated (e.g., energized) by interface unit 104 to facilitate delivery of energy (e.g., ablation energy, including PF A) to patient 101, such as in cases where electrodes pads 210 themselves serve as electrodes and/or in examples where electrode pads 210 are further connected to one or more electrodes. For example, interface unit 104 (e.g., including the generator and/or control circuitry associated with interface unit 104) is configured to activate a first group of electrode pads 210 (e.g., electrode pad 210-1, electrode pad 210-5, and electrode pad 210-9) and a second group of electrode pads 210 (e.g., electrode pad 110-3 and electrode pad 110-7) for a first time period, as well as activate a third group of electrode pads 210 (e.g., electrode pad 210-2 and electrode pad 210-6) and a fourth group of electrode pad 210 (e.g., electrode pad 210-4 and electrode pad 210-8) for a second time period different than the first time period. In some examples, interface unit 104 is configured to deliver energy between the first group of electrode pads 210 (e.g., electrode pad 210-1, electrode pad 210-5, and electrode pad 210-9) and the second group of electrode pads 210 (e.g., electrode pad 210-3 and electrode pad 210-7) during the first time period, where the first group of electrode pads 210 have a first polarity and the second group of electrode pads 210 have a second polarity different from the first polarity. In some examples, interface unit 104 is configured to deliver energy between the third group of electrode pads 210 (e.g., electrode pad 210-2 and electrode pad 210-6) and the fourth group of electrode pads 210 (e.g., electrode pad 210-4 and electrode pad 210-8) during the second time period, where the third group of electrode pads 210 have a first polarity and the fourth group of electrode pads 210 have a second polarity different from the first polarity. As described above, a first polarity can refer to a relative higher voltage and a second polarity can refer to a relatively lower voltage, or vice versa, such that current flows from the electrodes associated with electrode pads 210 with relatively higher voltage to electrodes associated with electrodes pads 210 with the relatively lower voltage. A voltage difference can be created between electrodes associated with electrode pads 210 having different polarities (e.g., different relative voltage level values), such that current flows between electrodes associated with electrode pads 210 having different polarity. [0090] Trace elements 242 and corresponding electrode pads 210 can be positioned and/or organized on elongated substrate 246 to reduce or even eliminate a possibility of unwanted electrical shorting between particular trace elements 242. In some examples, trace elements 242 corresponding to electrode pads 210 that have different polarities during a period of activation (e.g., that are active at the same time during a period of delivery of ablation energy) are disposed on opposite sides of elongated substrate 246 (e.g., on each of first face 241 A and second face 241B of elongated substrate 246). In some examples, multiple different respective groups of 242 and electrode pads 210 are configured to be activated at different times (e.g., at least two separate time periods). In some examples, groups of electrode pads 210 active during the different time periods can include the same number of electrode pads 210 (e.g., a number of electrode pads 210 per group). In other examples, groups of electrode pads 210 active during the different time periods can include a different number of electrodes (e.g., a number of electrode pads 210 per group).

[0091] With reference to the example of FIG. 2A and FIG. 2B, flex circuit 240 includes a first group of trace elements 242 (e.g., trace element 242-1, trace element 242- 5, and trace element 242-9) disposed on first face 241 A of elongated substrate 246 and a second group of trace elements (e.g., trace element 242-3 and trace element 242-7) disposed on second face 24 IB of elongated substrate 246. Each of the first group of trace elements 242 is electrically connected to a respective one of the first group of electrode pads 210 (e.g., trace element 242-1 is electrically connected to electrode pad 210-1, trace element 242-5 is electrically connected to electrode pad 210-5, and trace element 242-9 is electrically connected to electrode pad 210-9). Each of the second group of trace elements 242 is electrically connected to a respective one of the second group of electrode pads 210 (e.g., trace element 242-3 is electrically connected to electrode pad 210-3 and trace element 242-7 is electrically connected to electrode pad 210-7).

[0092] In this example, each of the first group of electrode pads 210 are configured, when activated by a generator (e.g., such as the generator and/or control circuitry of interface unit 104 as shown in FIG. 1 A) to have a first polarity and the each of the second group of electrode pads 210 are configured to have a second polarity, such that when activated by interface unit 104 (e.g., control circuitry of interface unit 104), the first group of electrode pads 210 and the second group of electrode pads 210 have a different polarity. In this way, bipolar energy can be delivered between the first group of electrode pads 210 and the second group of electrode pads 210. Elongated substrate 246 can be configured to electrically insulate the first group of trace elements 242 (e.g., trace element 242-1, trace element 242-5, and trace element 242-9) from the second group of trace elements 242 (e.g., trace element 242-3 and trace element 242-7) and vice versa, such as during a period of bipolar energy delivered between the first group of electrode pads 210 and the second group of electrode pads 210.

[0093] In a similar manner, with reference to the example of FIG. 2A and FIG. 2B, flex circuit 240 includes a third group of trace elements 242 (e.g., trace element 242-2 and trace element 242-6) disposed on first face 241 A of elongated substrate 246 and a fourth group of trace elements (e.g., trace element 242-4 and trace element 242-8) disposed on second face 24 IB of elongated substrate 246. Each of the third group of trace elements 242 is electrically connected to a respective one of the third group of electrode pads 210 (e.g., trace element 242-2 is electrically connected to electrode pad 210-2 and trace element 242-6 is electrically connected to electrode pad 210-6). Each of the fourth group of trace elements 242 is electrically connected to a respective one of a fourth group of electrode pads 210 (e.g., trace element 242-4 is electrically connected to electrode pad 210-4 and trace element 242-8 is electrically connected to electrode pad 210-8). In this example, each of the third group of electrode pads 210 are configured, when activated by a generator (e.g., such as the generator and/or control circuitry of interface unit 104 as shown in FIG. 1 A) to have a first polarity and the each of the fourth group of electrode pads 210 are configured to have a second polarity, such that when activated by interface unit 104 (e.g., control circuitry of interface unit 104), the third group of electrode pads 210 and the fourth group of electrode pads 210 have a different polarity. [0094] In this way, bipolar energy can be delivered between the third group of electrode pads 210 and the fourth group of electrode pads 210. Elongated substrate 246 can be configured to electrically insulate the third group of trace elements 242 (e.g., trace element 242-2 and trace element 242-6) from the fourth group of trace elements 242 (e.g., trace element 242-4 and trace element 242-8) and vice versa, such as during a period of bipolar energy delivered between the third group of electrode pads 210 and the fourth group of electrode pads 210.

[0095] In some examples, the first group of trace elements 242 (e.g., trace element 242-1, trace element 242-5, and trace element 242-9) and the third group of trace elements 242 (e.g., trace element 242-2 and trace element 242-6) are associated with electrode pads 210 (e.g., the first group of electrode pads 210 and the third group of electrode pads 210) that are not active at the same time. For example, as described in relation to previous examples, because the first group of electrode pads 210 (e.g., electrode pad 210-1, electrode pad 210-5, and electrode pad 210-9) and the third group of electrode pads 210 (e.g., electrode pad 210-2 and electrode pad 210-6) are not activated at the same time, there is little or no risk of shorting between the first group of trace elements 242 (e.g., trace element 242-1, trace element 242-5, and trace element 242-9) and the third group of trace elements 242 (e.g., trace element 242-2 and trace element 242-6). Thus even though first group of trace elements 242 (e.g., trace element 242-1, trace element 242-5, and trace element 242-9) and the third group of trace elements 242 (e.g., trace element 242-2 and trace element 242-6) are both disposed on first face 241 A of elongated substrate 246, and can be associated with electrode pads 210 having different polarities when activated, there is little or no risk of shorting between the first group of trace elements 242 and the third group of trace elements 242 (e.g., because the electrode pads 210 associated with the first group of trace elements 242 and the third group of trace elements 242 are not activate at the same time). However, in other examples, the electrode pads 210 associated with each of first group of electrode pads 210 (e.g., electrode pad 210-1, electrode pad 210-5, and electrode pad 210-9) and the third group of electrode pads 210 (e.g., electrode pad 210-2 and electrode pad 210-6), when activated, have the same polarity (e.g., even if activated at different times).

[0096] Similarly, in some examples, the second group of trace elements 242 (e.g., trace element 242-3 and trace element 242-7) and the fourth group of trace elements 242 (e.g., trace element 242-4 and trace element 242-8) are associated with electrode pads 210 (e.g., the second group of electrode pads 210 and the fourth group of electrode pads 210) that are not active at the same time. For example, as described in relation to previous examples, because the second group of electrode pads 210 (e.g., electrode pad 210-3 and electrode pad 210-7) and the fourth group of electrodes pad 210 (e.g., electrode pad 210-4 and electrode pad 210-8) are not activated at the same time, there is little or no risk of shorting between the second group of trace elements 242 (e.g., trace element 242-3 and trace element 242-7) and the fourth group of trace elements 242 (e.g., trace element 242-4 and trace element 242-8). Thus even though second group of trace elements 242 (e.g., trace element 242-3 and trace element 242-7) and the fourth group of trace elements 242 (e.g., trace element 242-4 and trace element 242-8) are both disposed on second face 241B of elongated substrate 246, and can be associated with electrode pads 210 having different polarities when activated, there is little or no risk of shorting between the second group of trace elements 242 and the fourth group of trace elements 242 (e.g., because the electrode pads 210 associated with the second group of trace elements 242 and the fourth group of trace elements 242 are not activate at the same time). However, in other examples, the electrode pads 210 associated with each of the second group of electrode pads 210 (e.g., electrode pad 210-3 and electrode pad 210-7) and the fourth group of electrode pads 210 (e.g., electrode pad 210-4 and electrode pad 210-8), when activated, have the same polarity (e.g., even if activated at different times).

[0097] In some examples, flex circuit 240, including elongated substrate 246, can include one or more features to facilitate electrical connection of the trace elements 242 to interface unit 104. In some examples, flex circuit 240 includes one or more features to facilitate electrical connection to at least a portion of catheter 102 (e.g., including connector 116), cable 113, and/or another intermediate component of medical system 100, such as for electrically connecting to interface unit 104. For example, as shown in the example of FIG. 2A and FIG. 2B, flex circuit 240 defines a plurality of holes 243 (shown individually as hole 243-1, hole 243-2, hole 243-3, hole 243-4, hole 243-5, hole 243-6, hole 243-7, hole 243-8, and hole 243-9 but collectively referred to herein as holes 243) at a proximal portion of the flex circuit 240, where plurality of holes 243 are configured to receive features (e.g., pins) of a connector (e.g., pins 362 of a connector 316 as shown in connection with the example of FIG. 3 A and FIG. 3B, which may be an example of connector 116 as shown in the example of FIG. IB). Each of holes 243 facilitates electrical connection of a respective trace element 242 to a channel of interface unit 104 (e.g., hole 243-1 is associated with trace element 242-1, hole 243-2 is associated with trace element 242-2, hole 243-3 is associated with trace element 242-3, and so on). Holes 243 may be sized, positioned, and/or otherwise configured such that when holes 243 receive respective mating features of a connector (e.g., pins 362 of a connector 316 of FIG. 3 A and FIG. 3B), respective trace elements 242 are electrically connected to the respective mating features of the connector. Such mating features (e.g., holes 243 that correspond to respective mating features of a connector, such as connector 316) can facilitate a relatively easier assembly and/or connection of catheter 102 to interface unit 104, and may prevent errors associated with electrically connecting particular electrode pads 210 associated with particular trace elements 242 to incorrect channels of interface unit 104.

[0098] In some examples, flex circuit 240 includes one or more features (e.g., structural features) to facilitate relatively greater mechanical robustness and/or reduce mechanical fatigue (e.g., as compared to other flex circuits and/or other means of electrical connection). In some examples, flex circuit 240 defines at least one twist (e.g., a twist along the length of elongated substrate 246, such as along the x-axis direction according to the orthogonal x-y-z axes in the example of FIG. 2A and FIG. 2B). In some examples, flex circuit 240 defines a series of twists, such as to form a helix or a coil (e.g., elongated substrate 246 can be twisted around a longitudinal axis extending in the x-axis direction). In some examples, with reference to FIG. IB, the twist, helix, and/or coil is between a portion of flex circuit 240 associated with proximal portion 108 (e.g., which can include a handle) and distal portion 106 of catheter 102. The twist, helix, and/or coil of flex circuit 240 may enable flex circuit 240 to better withstand and accommodate external forces during an ablation procedure, such as external forces that can cause one or more of axial extension, axial compression, axial bending, torsion, and/or another deformation of flex circuit 240. The twist, helix, and/or coil can define a lumen therethrough, which can be configured to accommodate other structural components (e.g., a guidewire).

[0099] In some examples, at least a portion of flex circuit 240 is sized, shaped, positioned, and/or otherwise configured according to one or more other corresponding features of catheter 102. For example, as shown in the example of FIG. 2A and FIG. 2B, a distal portion of flex circuit 240 (e.g., a portion of flex circuit farther in the positive x-axis direction according to the orthogonal x-y-z axes in FIG. 2A and FIG. 2B) defines a predefined curve. As shown in the example of FIG. 2A and FIG. 2B, the predefined curve includes an approximately circular shape in a plane parallel to a plane defined by the x- axis and z-axis). In some examples, electrode pads 210 are configured to electrically connect to respective ones of trace elements 242 proximate to the predefined curve. In some examples, electrode pads 210 are distributed around the predefined curve of flex circuit 240. In some examples, the predefined curve of the distal portion of flex circuit 240 corresponds to a shape of expandable element 111 of catheter 102. The predefined curve may enable flex circuit to better accommodate transformation of expandable element 111 of catheter 102 between the delivery and deployed configurations, as discussed in relation to previous examples.

[0100] In some examples, as shown in the example of FIG. 2C, trace elements 242 can additionally or alternatively be grouped on lateral sides of elongated substrate 246 (e.g., where lateral sides correspond to being relatively farther toward a side of elongated substrate 246 in either the positive or negative z-axis directions according to the orthogonal x-y-z axes in the example of FIG. 2C). As shown in the example of FIG. 2C, a plane 251 defines the interface between a first lateral side and a second lateral side of elongated substrate 246, where the first lateral side includes the side of elongated substrate 246 extending in the positive z-axis direction from plane 251 (e.g., the right-hand side of plane 251 in the example of FIG. 2C), and a second lateral side includes the side of elongated substrate 246 extending in the negative z-axis direction from plane 251 (e.g., the left-hand side of plane 251 in the example of FIG. 2C). Grouping trace elements 242 on each of the first lateral side and the second lateral side of elongated substrate 246 can facilitate spacing between groups on respective lateral sides of elongated substrate 246, which may reduce or eliminate the possibility of unwanted electrical shorting between trace elements 242 on each respective side. Grouping trace elements 242 on each of the first lateral side and the second lateral side of elongated substrate 246 can correspond to grouping of trace elements 242 at a proximal portion of flex circuit 240, such as grouping corresponding to connector pins of a connector configured to interface with flex circuit 240 (e.g., pins 362 of connector 326, as discussed in connection with FIG. 3A and FIG. 3B). Grouping trace elements 242 on each of the first lateral side and the second lateral side of elongated substrate 246 can enable each of trace elements 242 to extend between the proximal and distal portion of flex circuit 240 without having to physically cross over each other.

[0101] As shown in the example of FIG. 2C, a first subset of trace elements 242 corresponding to at least some of electrode pads 210 configured to be activated during a first time period of energy delivery are positioned on the first side of elongated substrate 246 (e.g., on the side of plane 251 extending in the positive z-axis direction). In particular, the first group of trace elements 242 (e.g., trace element 242-1, trace element 242-5, and trace element 242-9) corresponding to the first group of electrode pads 210 and the second group of trace elements 242 (e.g., trace element 242-3 and trace element 242-7) corresponding to the second group of electrode pads 210 are positioned on the first lateral side of elongated substrate 246, such as on the side of plane 251 extending in the positive z-axis direction. As discussed in relation to previous examples, the first group of electrode pads 210 and the second group of electrode pads 210 can be configured to be simultaneously activated during a first period (e.g., time period) of energy delivery.

[0102] As shown in the example of FIG. 2C, a second subset of trace elements 242 corresponding to at least some of electrode pads 210 configured to be activated during a second time period of energy delivery are positioned on the second side of elongated substrate 246 (e.g., on the side of plane 251 extending in the negative z-axis direction). In particular, the third group of trace elements 242 (e.g., trace element 242-2 and trace element 242-6) corresponding to the third group of electrode pads 210 and the fourth group of trace elements 242 (e.g., trace element 242-4 and trace element 242-8) corresponding to the fourth group of electrode pads 210 are positioned on the second lateral side of elongated substrate 246, such as on the side of plane 251 extending in the negative z-axis direction. As discussed in relation to previous examples, the third group of electrode pads 210 and the fourth group of electrode pads 210 can be configured to be simultaneously activated during a second period (e.g., time period) of energy delivery.

[0103] In some examples, each of trace elements 242 are laterally spaced apart (e.g., spaced apart in the z-axis direction according to the orthogonal x-y-z axes in the example of FIG. 2C). In some examples, the lateral spacing between trace elements 242 extends at least between a proximal portion of elongated substrate 246 and a distal portion of elongated substrate 246 (e.g., with the proximal portion of elongated substrate 246 extending toward the negative x-axis direction and the distal portion of elongated substrate 246 extending toward the positive x-axis direction, as best shown according to the orthogonal x-y-z axes in the example of FIG. 2A and FIG 2B). As shown in the example of FIG. 2C, laterally adjacent trace elements 242 are laterally spaced apart by at least a lateral distance LI. In some examples, distance LI is corresponds to a minimum lateral distance that a suitable manufacturing method is capable of producing (e.g., while still maintaining at least a finite separation between laterally adjacent trace elements 242, such as for an adhesive that is disposed between adjacent trace elements 242). Distance LI can be a relatively small distance because of the relatively low risk associated with shorting (e.g., electrical connection) between electrical trace elements 242 of a given group of electrical trace elements 242. As trace elements 242 of a given group of trace elements 242 all have the same polarity when activated, problems caused because of shorting (e.g., electrical contact) between laterally adjacent trace elements 242 of a given group of trace elements 242 are relatively low and/or nonexistent (e.g., as compared to potential problems cause by shorting between trace elements 242 of different polarity, which can cause disruptions to energy delivery to patient 101). In some examples, distance LI is less than 0.0050 inches, such as about 0.0040 inches. In other examples, distance LI is less than 0.0040 inches (e.g., depending on the capability of the manufacturing method used to create flex circuit 240 with trace elements 242).

[0104] In some examples, laterally adjacent ones of trace elements 242 corresponding to different groups of trace elements 242 are spaced apart by at least a second lateral distance L2. In some examples, lateral distance L2 is greater than lateral distance LI. In some examples, lateral distance L2 is greater than lateral distance LI by at least a safety factor of 50 percent (e.g., wherein distance L2 is 1.5 times distance LI). For example, lateral distance can be greater than 0.0050 inches, such as about 0.0060 inches or greater. In some examples, distance L2 is a sufficient distance such that a material filling the gap between trace 242-6 and trace element 242-9 can electrically insulate these respective traces in examples where all trace elements 242 on the same face (e.g., first face 241 A of elongated substrate 246) are active at the same time (e.g., which may be the case for relatively lower voltage applications). Additionally, in examples where lateral distance L2 is greater than lateral distance LI, a user may be able to more easily visually distinguish between different groups of trace elements 242 on a given face of elongated substrate 246 (e.g., between the first group of trace elements 242 comprising trace element 242-1, trace element 242-5, and trace element 242-9 and the third group of trace elements 242 comprising trace element 242-2 and trace element 242-6, in which both of the first group of trace elements 242 and the third group of trace elements 242 are disposed on first face 241A of elongated substrate 246).

[0105] As shown in the example of FIG. 2C, elongated substrate 246 defines a suitable thickness L3 to inhibit electrical shorting between trace elements 242 on opposite sides (e.g., on first face 241 A and second face 241B) of elongated substrate 246. In some examples, L3 is about 0.0005 inches to about 0.0030 or any value therebetween, such as about 0.0010 inches. In some examples, thickness L3 of elongated substrate 246 corresponds to a level of voltage and/or current supplied to trace elements 242 (e.g., to reduce a risk of shorting between groups of trace elements 242 disposed on elongated substrate 246). In examples where relatively high voltage levels and/or current levels are used for energy (e.g., such as in the case of PFA which can include voltages of 1500 V to 4000 V), thickness L3 of elongated substrate 246 is sufficient such as to enable elongated substrate 246 to electrically insulate different groups of trace elements 242 disposed on opposite faces of elongated substrate 246 from each other, even during movement and/or deformation of one or more portions of flex circuit 240 (e.g., which may occur during the course of an ablation procedure).

[0106] Although the example of FIG. 2A, FIG. 2B, and FIG. 2C is described as having nine trace elements 242 associated with nine electrode pads 210, flex circuit 240 can have any suitable number of trace elements 242 and any suitable number of electrode pads 210 (e.g., two trace elements 242 and two corresponding electrode pads 210, such as in the case of bipolar energy delivery, or more trace elements 242 and corresponding electrode pads 210, including three, four, five, ten, twenty, one hundred, or more, or any number therebetween). In some examples, a respective one of trace elements 242 is connected to more than one of electrode pads 210 (e.g., such that more than one of electrode pads 210 can be controlled together). Additionally, while the example of FIG. 2A, FIG. 2B, and FIG. 2C is described as having two or three electrode pads 210 and such that four or five electrodes are active at any given time during the first time period and the second time period, flex circuit 240 can have any number of groups of electrode pads 210 configured to be active during any number of time periods (e.g., groups can include two, three, four, five, ten, twenty, one hundred, or more electrode pads and/or associated electrodes, and the number of electrode groups can include one, two, three, four, five, ten, twenty, one hundred, or more groups of electrodes). Further, in the case of monopolar and/or unipolar energy, other modalities, and/or combinations thereof, the number of electrodes and or other delivery elements can include any suitable number.

[0107] FIG. 3 A and FIG. 3B show an approximately isometric view and a side view, respectively, of an example connector 316 configured to interface with (e.g., mechanically couple to) a proximal portion of an ablation catheter (e.g., catheter 102 in the example of FIG. 1 A and FIG. IB). In some examples, connector 316 is also configured to interface with (e.g., mechanically couple to and/or electrically couple to) a flex circuit (e.g., flex circuit 140 of FIG. IB and/or flex circuit 240 of FIG. 2A and FIG. 2B). Connector 316 may be an example of connector 116 as shown and described in connection with FIG. IB. Connector 316 may be configured similarly to connector 116, except as described herein. Elements from the examples of FIG. 1 A, FIG. IB, FIG. 2A, FIG. 2B, and/or FIG. 2C are referenced herein, such as to illustrate corresponding and/or mating features of connector 316.

[0108] In some examples, connector 316 includes features to facilitate coupling (e.g., mechanical coupling and/or electronical coupling) between flex circuit 140 and cable 113, where cable 113 is configured to couple to interface unit 104. The mating features of connector 316 (e.g., that mate with either or both of portions of cable 113 and/or flex circuit 140) can enable a relatively faster, easier, and/or more reliable coupling (e.g., mechanical coupling and/or electrical coupling) between catheter 102 and interface unit 104. As shown in the example of FIG. 3 A and FIG. 3B, connector 316 includes a plurality of pins 362 configured to interface with (e.g., mechanically couple and/or electrically couple to) mating features of a flex circuit, such as holes 243 of flex circuit 240 of FIG. 2A and FIG. 2B. In some examples, pins 362 define a positioning (e.g., spacing between adjacent pins 362) and size such that pins 362 are configured to be received by holes 243 of flex circuit. Upon being received by holes 243, each of pins 362 is electrically connected to a respective one of trace elements 242, and ultimately respective ones of electrode pads 210. Connector 316 may also be connected to an interface unit (e.g., interface unit 104), such as to facilitate connection between interface unit 104 and electrode pads 210. [0109] In some examples, connector 316 is configured to interface (e.g., mechanically interface and/or electrically interface) with at least another part of proximal portion 108 (e.g., the handle portion) of catheter 102. In some examples, connector 316 is configured to fit into a proximal portion of the handle of catheter 102. In some examples, connector 316 is configured to reversibly connect and/or disconnect from the handle, such as to connect interface unit 104 to catheter 102. In some examples, connector 316 is configured to reversibly connect and/or disconnect from cable 113 and/or another intermediate component to facilitate electrical connection with interface unit 104. In this way, connector 316 can facilitate a relatively easy and/or simple way to connect and/or disconnect catheter 102 from interface unit 104, which may enable a user (e.g., a clinician) to quickly connect different ones of catheter 102 to interface unit 104.

[0110] FIG. 4 is a conceptual diagram showing a cross-sectional view of a flex circuit 440, which may be an example of flex circuit 140 of FIG. IB. Flex circuit 440 may be configured in a similar manner as flex circuit 140, except as described herein. The cross- sectional view of flex circuit 440 is similar to the cross-sectional view of flex circuit 240 of FIG. 2C. Flex circuit 440 may be configured in a similar manner as flex circuit 240, except as described herein.

[oni] In the example of FIG. 4, flex circuit 440 includes a plurality of trace elements 442 (shown individually as trace element 442-1, trace element 442-2, trace element 442-3, trace element 442-4, trace element 442-5, trace element 442-6, trace element 442-7, trace element 442-8, and trace element 442-9 but collectively referred to herein as trace elements 442). Trace elements 442 may be configured similarly to trace elements 242 of FIG. 2A, FIG. 2B, and FIG. 2C, except as described herein. In the example of FIG. 4, trace elements 442 are disposed on an elongated substrate 446, which may be configured similar to elongated substrate 246 except as described herein. As shown in the example of FIG. 4, elongated substrate 446 defines least a first face 441 A and a second face 44 IB, with at least some of trace elements 442 disposed on each of first face 441A and second face 441B.

[0112] In some examples, flex circuit 440 is configured to have one or more additional trace elements disposed on elongated substrate 446 (e.g., additional trace elements other than trace elements 442). In some examples, flex circuit 440 includes additional trace element 444 positioned on elongated substrate 446. Because of the relatively small cross- sectional profile of each of the trace elements 442 that electrically connect to respective electrodes and/or electrode pads, flex circuit 440 can be configured to accommodate one or more of trace element 444, which may facilitate addition of additional types of electrodes (e.g., reference electrodes) and/or sensors incorporate into catheter 102.

[0113] In some examples, additional trace element 444 is a sensor trace element and configured to facilitate electrical connection of one or more sensors (e.g., sensors at distal portion 106 of catheter 102) to interface unit 104. In some examples, the one or more sensors include a temperature sensor configured to receive a signal indicative of temperature (e.g., as discussed in relation with FIG. 1 A). In these examples, additional trace element 444 is configured as a sensor trace element to facilitate electrical connection between the sensor and interface unit 104 by at least electrically connecting to the sensor. In some examples, the one or more sensors include one or more position sensors (e.g., sensors that are configured for use with the positioning subsystem of interface unit 104, as discussed in relation with FIG. 1 A). In such examples, additional trace element 444 is configured as a position trace element to facilitate electrical connection between the position sensors and interface unit 104 by at least electrically connecting to the position sensor.

[0114] In some examples, additional trace element 444 is configured as a reference electrode trace element, such as to facilitate electrical connection between one or more reference electrodes (e.g., reference electrodes at distal portion 106 of catheter 102) to interface unit 104 of FIG. 1 A. Reference electrodes can include elements that are configured to act as a return path for current, such as may be used in impedance measurements. In some examples, the one or more reference electrodes facilitate impedance measurements. In some examples, the one or more reference electrodes are not activated by interface 104 to deliver energy, even when other electrodes (e.g., electrodes 110 of FIG. 1 A) are activated to deliver energy. In these examples, additional trace element 444 is configured as a reference electrode trace element to facilitate electrical connection between the reference electrode and interface unit 104 by at least electrically connecting to the reference electrode (e.g., to facilitate impedance measurements).

[0115] In some examples, additional trace element 444 is configured as a neutral electrode trace element, such as to facilitate electrical connection between one or more neutral electrodes (e.g., neutral electrodes at distal portion 106 of catheter 102) to interface unit 104 of FIG. 1A. Neutral electrodes can include elements configured as a return path for current (e.g., in cases of unipolar energy delivery).

[0116] FIG. 5 is a conceptual diagram illustrating an example flex circuit 540, which may be an example of flex circuit 140 of FIG. IB. Flex circuit 540 may be configured in a similar manner as flex circuit 140, except as described herein. Some components of FIG. 1 A and FIG. IB will be referenced herein to demonstrate the functionality, physical orientation, and/or configuration of components flex circuit 540 of FIG. 5. Additionally, flex circuit 540 may be configured in a similar manner as flex circuit 240 of FIG. 2 A, FIG. 2B, and FIG. 2c, except as described herein.

[0117] As shown in the example of FIG. 5, flex circuit 540 includes a plurality of trace elements 542 (shown individually as trace element 542-1, trace element 542-2, trace element 542-5, trace element 542-6, and trace element 542-9 but collectively referred to herein as trace elements 542). In some examples, trace elements 542 are disposed on a flexible elongated substrate 546 such that trace elements 542 extend between a proximal portion (e.g., which may include a proximal end) and a distal portion (e.g., which may include a distal end) of elongated substrate 546. Elongated substrate 546 and trace elements 542 can be configured similarly to elongated substrate 246 and trace elements 242, respectively, of FIG. 2 A, FIG. 2B, and FIG. 2C. Flex circuit 540 can include additional trace elements 542 on a face of elongated substrate 546 not shown in the example of FIG. 5 (e.g., similar to the trace elements 242 including trace element 242-3, trace element 242-4, trace element 242-7, and trace element 242-8 disposed on second face 24 IB of elongated substrate 246 as shown in the example of FIG. 2B).

[0118] In the example of FIG. 5, flex circuit 540 includes a plurality of electrode pads 510 (shown individually as electrode pad 510-1, electrode pad 510-2, electrode pad 510-3, electrode pad 510-4, electrode pad 510-5, electrode pad 510-6, electrode pad 510-7, electrode pad 510-8, and electrode pad 510-9 but collectively referred to herein as electrode pads 510). At least some of electrode pads 510 are shown as electrically connected to respective ones of trace elements 542. Electrode pads 510 can be configured in a similar manner as electrode pads 210 of FIG. 2 A and FIG. 2B except as described herein.

[0119] In some examples, elongated substrate 546 of flex circuit 540 includes one more structural features and or configuration to facilitate a relatively simpler manufacturing and/or assembly of flex circuit 540 into a final form factor (e.g., such that flex circuit can be integrated with other components of a medical devices system, including various components of catheter 102). For example, as shown in the example of FIG. 5, elongated substrate 546 of the flex circuit 540 defines a split in elongated substrate 546 such that a distal portion of elongated substrate 546 forms a first substrate distal portion 552A and a second substrate distal portion 552B. In some examples, each of first substrate distal portion 552A and second substrate distal portion 552B define a similar form factor and/or shape (e.g., each of first substrate distal portion 552A and second substrate distal portion 552B define a predefined curve shape).

[0120] In some examples, each of first substrate distal portion 552A and second substrate distal portion 552B includes a respective subset of trace elements 542 and/or a subset of electrode pads 510. For example, as shown in the example of FIG. 5, first substrate distal portion 552A includes a first group of trace elements 542 (e.g., trace element 542-1, trace element 542-5, and trace element 542-9), wherein each of the first group of trace elements 542 is electrically connected to a respective electrode of a first group of electrode pads 510 (e.g., electrode pad 510-1, electrode pad 510-5, and electrode pad 510-9). In the example of FIG. 5, second substrate distal portion 552B includes a third group of trace elements 542 (e.g., trace element 542-2 and trace element 542-6), wherein each of the third group of trace elements 542 is electrically connected to a respective electrode of a third group of electrode pads 510 (e.g., electrode pad 510-2 and electrode pad 510-6). First substrate distal portion 552A and second substrate distal portion 552B can include other groups of trace elements 542 and corresponding electrode pads 510 not shown in the example of FIG. 5. For example, a face of elongated substrate 546 not shown in the example of FIG. 5, including a face of each of first substrate distal portion 552A and second substrate distal portion 552B, can include a second group of trace elements 542 and a fourth group of trace elements 542, respectively, similar to the example of FIG. 2B. [0121] In some examples, first substrate distal portion 552A and second substrate distal portion 552B are configured to be mechanically coupled (e.g., fixedly mechanically coupled). For example, first substrate distal portion 552A and second substrate distal portion 552B can be mechanically coupled such as to create a single predefined loop corresponding to another feature of an ablation catheter (e.g., a shape of expandable element 111 of catheter 102 of FIG. 1 A and FIG. IB). For example, first substrate distal portion 552A and second substrate distal portion 552B can be mechanically coupled to each other such as to form a single, predefined curve shape (e.g., like the predefined curve shape of the distal portion of flex circuit 240 as shown in the example of FIG. 2 A and FIG. 2B). The split portion of elongated substrate 546 including first substrate distal portion 552A and second substrate distal portion 552B that are subsequently mechanically coupled (e.g., affixed) can facilitate relatively easier assembly (e.g., because of relatively less complex arrangement of trace elements 542 needed when elongated substrate 546 splits to form each of first substrate distal portion 552A and second substrate distal portion 552B). [0122] In some examples, electrode pads 510 associated with first substrate distal portion 552A (e.g., including at least electrodes electrode pad 510-1, electrode pad 510-5, and electrode pad 510-9) are configured to be activated (e.g., by interface unit 104) during a first time period. In some examples, electrode pads 510 associated with second substrate distal portion 552B (e.g., electrode pad 510-2 and electrode pad 510-6) are configured to be activated (e.g., by interface unit 104) during a second time period (e.g., wherein the second time period is different and distinct from the first time period).

[0123] FIG. 6 is a flow diagram illustrating an example technique for introducing and positioning a medical system (e.g., which may include an ablation catheter). The technique is described with reference to medical system 100 of FIG. 1 A. However, the technique may be applied to other medical systems in other examples.

[0124] While the technique of FIG. 6 is described with respect to medical system 100 of FIG. 1 A, which can include a separate catheter 102 and interface unit 104, it is understood that catheter 102 can additionally or alternatively include circuitry configured to execute one or more functions attributed to interface unit 104. In some examples, the technique of FIG. 6 can be performed with one or more of catheter 102, interface unit 104, the circuitry attributed to interface unit 104, components of each of catheter 102 or interface unit 104, and/or suitable combinations thereof.

[0125] In the example of FIG. 6, the technique includes introducing one or more components of a medical system 100, including a medical device (e.g., catheter 102) including plurality of electrodes 110 at distal portion 106 of the medical device (e.g., catheter 102) into vasculature of patient 101 (600). The medical device (e.g., catheter 102) can be introduced into patient 101 via an introducer sheath, a guide catheter, a guide wire, another introducer tool, or a combination thereof. [0126] In the example of FIG. 6, the technique further includes advancing one or more components of a medical system 100, including the medical device (e.g., catheter 102) until distal portion 106 (e.g., including electrodes 110) are at or near target tissue of patient 101 (602). In some examples, the medical device (e.g., catheter 102) is advanced through vasculature of a patient 101 using one or more of a guide catheter, a sheath, a guidewire, another navigation tool, or a combination thereof. In some examples, target tissue of patient 101 includes cardiac tissue. In some examples, the positioning subsystem of interface unit 104 (e.g., as discussed in connection with FIG. 1 A) is used to locate and navigate catheter 102 to the target tissue of patient 101.

[0127] In some examples, the technique further includes deploying electrodes 110 (e.g., via an expandable element 111) into proximity and/or contact with tissue. In some examples, once deployed, and/or prior to deployment, interface unit 104 is configured to sense one or more patient parameters (e.g., electrical signals) from tissue of patient 101 and/or deliver energy (e.g., electrical energy, such as pulsed field ablation) to tissue of patient 101.

[0128] In some examples, the technique further includes sensing, via interface unit 104, one or more signals. For example, interface unit 104 can receive one or more signals indicative of one or more patient statuses or conditions and/or signals that indicate an effectiveness of therapy. In some examples, as discussed in connection with previous examples, catheter 102 includes delivery elements 110 and/or other sensors configured to receive signals indicative of one or more parameters. As described in this disclosure, catheter 102 can include a flex circuit (e.g., flex circuit 140) that carries electrical signals from delivery elements 110 and/or the one or more sensors to interface unit 104 in sensing the one or more signals. Additional or alternatively, separate catheters and/or other separate sensors are used in sensing signals indicate of one or more patient statuses or conditions and/or signals that indicate an effectiveness of delivered energy.

[0129] In some examples, the technique further includes delivering, by interface unit 104, energy to tissue of patient 101. In some examples, as described throughout this disclosure, interface unit 104 (e.g., including processing circuitry, control circuitry, and/or energy generation circuitry thereof), delivers energy (e.g., cardiac ablation energy) to one or more areas of tissue (e.g., cardiac tissue) of patient 101. In some examples, interface unit 104 delivers energy to tissue of patient 101 via delivery elements 110 of catheter 102. As described in this disclosure, catheter 102 can include a flex circuit (e.g., flex circuit 140) that carries electrical signals from interface unit 104 to delivery elements 110 in in order to deliver energy to tissue of patient 101.

[0130] In some examples, the technique further includes transforming catheter 102 (e.g., expandable element 111 of catheter 102) back to the delivery (e.g., compressed) configuration, and withdrawing catheter 102 from patient 101.

[0131] The techniques described in this disclosure, including those attributed to medical system 100, interface unit 104, and/or various constituent components, may be implemented, at least in part, in hardware, software, firmware or any combination thereof. For example, various aspects of the techniques may be implemented within one or more processors, including one or more microprocessors, digital signal processors (DSPs), application specific integrated circuits (ASICs), field-programmable gate array (FPGAs), or any other equivalent integrated or discrete logic circuitry, as well as any combinations of such components, embodied in programmers, such as clinician or patient programmers, medical devices, or other devices. Processing circuitry, control circuitry, and sensing circuitry, as well as other processors and controllers described herein, may be implemented at least in part as, or include, one or more executable applications, application modules, libraries, classes, methods, objects, routines, subroutines, firmware, and/or embedded code, for example. In addition, analog circuits, components and circuit elements may be employed to construct one, some or all of the processing circuitry, instead of or in addition to the partially or wholly digital hardware and/or software described herein. Accordingly, analog or digital hardware may be employed, or a combination of the two.

[0132] The term “processor,” and “processing circuitry” as used herein, such as may refer to any of the foregoing structure or any other structure suitable for implementation of the techniques described herein. Also, the techniques could be fully implemented in one or more circuits or logic elements.

[0133] The techniques of this disclosure may be implemented in a wide variety of devices or apparatuses, including a wireless handset, an integrated circuit (IC) or a set of ICs (e.g., a chip set). Various components, modules, or units are described in this disclosure to emphasize functional aspects of devices configured to perform the disclosed techniques, but do not necessarily require realization by different hardware units. Rather, as described above, various units may be combined in a hardware unit or provided by a collection of interoperative hardware units, including one or more processors as described. [0134] In one or more examples, the functions described in this disclosure may be implemented in hardware, software, firmware, or any combination thereof. If implemented in software, the functions may be stored on, as one or more instructions or code, a computer-readable medium and executed by a hardware-based processing unit. The computer-readable medium may be an article of manufacture including a non-transitory computer-readable storage medium encoded with instructions. Instructions embedded or encoded in an article of manufacture including a non-transitory computer-readable storage medium encoded, may cause one or more programmable processors, or other processors, to implement one or more of the techniques described herein, such as when instructions included or encoded in the non-transitory computer-readable storage medium are executed by the one or more processors. Example non-transitory computer-readable storage media may include random-access memory (RAM), read-only memory (ROM), programmable ROM (PROM), erasable programmable ROM (EPROM), electronically erasable programmable ROM (EEPROM), flash memory, a hard disk, a compact disc ROM (CD- ROM), a floppy disk, a cassette, magnetic media, optical media, or any other computer readable storage devices or tangible computer readable media.

[0135] In some examples, a computer-readable storage medium includes a non- transitory medium. The term “non-transitory” may indicate that the storage medium is not embodied in a carrier wave or a propagated signal. In certain examples, a non-transitory storage medium may store data that can, over time, change (e.g., in RAM or cache).

[0136] The functionality described herein may be provided within dedicated hardware and/or software modules. Depiction of different features as modules or units is intended to highlight different functional aspects and does not necessarily imply that such modules or units must be realized by separate hardware or software components. Rather, functionality associated with one or more modules or units may be performed by separate hardware or software components, or integrated within common or separate hardware or software components. Also, the techniques could be fully implemented in one or more circuits or logic elements.

[0137] In some examples, such as when used to describe numerical values, “about” or “approximately” refers to a range within the numerical value resulting from manufacturing tolerances and/or within 1%, 5%, or 10% of the numerical value. For example, a length of about 10 mm refers to a length of 10 mm to the extent permitted by manufacturing tolerances, or a length of 10 mm +/- 0.1 mm, +/- 0.5 mm, or +/- 1 mm in various examples.

[0138] This disclosure includes the following non-limiting examples.

[0139] Example 1 : A medical system includes a handle; an elongated body; a plurality of electrodes at a distal portion of the elongated body; and a flex circuit extending at least between the handle and the distal portion of the elongated body, the flex circuit including: an elongated substrate defining at least a first face and a second face opposite the first face; and a plurality of trace elements disposed on the elongated substrate, each of the plurality of trace elements electrically connected to at least one electrode of the plurality of electrodes, wherein a first group of trace elements of the plurality of trace elements is disposed on the first face of the elongated substrate, the first group of trace elements electrically connected to a first group of electrodes of the plurality of electrodes, wherein a second group of trace elements of the plurality of trace elements is disposed on the second face of the elongated substrate, the second group of trace elements electrically connected to a second group of electrodes the plurality of electrodes, and wherein, when activated, the first group of electrodes and the second group of electrodes have a different polarity. [0140] Example 2: The medical system of example 1, further comprising control circuitry, wherein a third group of trace elements of the plurality of trace elements is disposed on the first face of the elongated substrate, the third group of trace elements electrically connected to a third group of electrodes of the plurality of electrodes, wherein a fourth group of trace elements of the plurality of trace elements is disposed on the second face of the elongated substrate, the fourth group of trace elements electrically connected to a fourth group of electrodes of the plurality of electrodes, wherein the control circuitry is configured to activate the first group of electrodes and the second group of electrodes for a first time period, and wherein the control circuitry is configured to activate the third group of electrodes and the fourth group of electrodes for a second time period different than the first time period, wherein, when activated, the third group of electrodes and the fourth group of electrodes have a different polarity.

[0141] Example 3: The medical system of example 2, wherein the first group of trace elements and the second group of trace elements are disposed on a first lateral side of the elongated substrate, and wherein the third group of trace elements and the fourth group of trace elements are disposed on a second lateral side of the elongated substrate opposite the first lateral side.

[0142] Example 4: The medical system of any of examples 2 and 3, wherein laterally adjacent trace elements of the plurality of trace elements are spaced apart by at least a first lateral distance, and wherein the first group of trace elements and the second group of trace elements are spaced apart from the third group of trace elements and the fourth group of trace elements by at least a second lateral distance, the second lateral distance being greater than the first lateral distance.

[0143] Example 5: The medical system of example 4, where the first lateral distance is at least about 0.0040 inches, and wherein the second lateral distance is at least about 0.0060 inches.

[0144] Example 6: The medical system of any of examples 1 through 5, further comprising one or more sensors at the distal portion of the elongated body, wherein the flex circuit includes one or more sensor trace elements disposed on the elongated substrate and electrically coupled to the one or more sensors, and wherein the one or more sensors include a temperature sensor or a position sensor.

[0145] Example 7: The medical system of any of examples 1 through 6, further comprising a reference electrode at the distal portion of the elongated body, wherein the flex circuit includes a reference electrode trace element electrically coupled to the reference electrode.

[0146] Example 8: The medical system of any of examples 1 through 7, wherein the elongated substrate of the flex circuit splits to form a first substrate distal portion and a second substrate distal portion, and wherein the first substrate distal portion and the second substrate distal portion are configured to be mechanically coupled.

[0147] Example 9: The medical system of any of examples 1 through 8, where the flex circuit defines a plurality of holes at a proximal portion of the flex circuit, the plurality of holes configured to receive pins of a connector to electrically couple the plurality of trace elements to the connector.

[0148] Example 10: The medical system of example 9, wherein the connector is configured to interface with the handle. [0149] Example 11 : The medical system of any of examples 1 through 10, wherein the flex circuit defines at least one twist along a portion of the flex circuit extending between the handle and distal portion of the elongated body.

[0150] Example 12: The medical system of any of examples 1 through 11, wherein the flex circuit defines a helix along at least a portion of the flex circuit extending between the handle and the distal portion of the elongated body.

[0151] Example 13: The medical system of any of examples 1 through 12, wherein the plurality of trace elements includes at least nine trace elements.

[0152] Example 14: The medical system of any of examples 1 through 13, further comprising control circuitry configured to deliver energy between at least some of the plurality of electrodes at a voltage of at least 1500 volts.

[0153] Example 15: The medical system of any of examples 1 through 14, wherein a distal portion of the flex circuit where the plurality of trace elements are electrically connected to the plurality of electrodes includes a predefined curve.

[0154] Example 16: A method includes introducing a medical system into vasculature of a patient, the medical system including: a handle, an elongated body, a plurality of electrodes at a distal portion of the elongated body; and a flex circuit extending at least between the handle and the distal portion of the elongated body, the flex circuit including, an elongated substrate defining at least a first face and a second face opposite the first face, and a plurality of trace elements disposed on the elongated substrate, each of the plurality of trace elements electrically connected to at least one electrode of the plurality of electrodes, wherein a first group of trace elements of the plurality of trace elements is disposed on the first face of the elongated substrate, the first group of trace elements electrically connected to a first group of electrodes of the plurality of electrodes, wherein a second group of trace elements of the plurality of trace elements is disposed on the second face of the elongated substrate, the second group of trace elements electrically connected to a second group of electrodes the plurality of electrodes, and wherein, when activated, the first group of electrodes and the second group of electrodes have a different polarity; and advancing the medical system through the vasculature until the distal portion is at or near target tissue within the patient.

[0155] Example 17: The method of example 16, wherein the medical system includes control circuitry; wherein a third group of trace elements of the plurality of trace elements is disposed on the first face of the elongated substrate, the third group of trace elements electrically connected to a third group of electrodes of the plurality of electrodes, wherein a fourth group of trace elements of the plurality of trace elements is disposed on the second face of the elongated substrate, the fourth group of trace elements electrically connected to a fourth group of electrodes of the plurality of electrodes, wherein the control circuitry is configured to activate the first group of electrodes and the second group of electrodes for a first time period, and wherein the control circuitry is configured to activate the third group of electrodes and the fourth group of electrodes for a second time period different than the first time period, wherein, when activated, the third group of electrodes and the fourth group of electrodes have a different polarity.

[0156] Example 18: The method of example 17, wherein the first group of trace elements and the second group of trace elements are disposed on a first lateral side of the elongated substrate, and wherein the third group of trace elements and the fourth group of trace elements are disposed on a second lateral side of the elongated substrate opposite the first lateral side.

[0157] Example 19: The method of any of examples 17 and 18, wherein laterally adjacent trace elements of the plurality of trace elements are spaced apart by at least a first lateral distance, and wherein the first group of trace elements and the second group of trace elements are spaced apart from the third group of trace elements and the fourth group of trace elements by at least a second lateral distance, the second lateral distance being greater than the first lateral distance.

[0158] Example 20: The method of example 19, where the first lateral distance is at least about 0.0040 inches, and wherein the second lateral distance is at least about 0.0060 inches.

[0159] Example 21 : The method of any of examples 16 through 20, further comprising one or more sensors at the distal portion of the elongated body, wherein the flex circuit includes one or more sensor trace elements disposed on the elongated substrate and electrically coupled to the one or more sensors, and wherein the one or more sensors include a temperature sensor or a position sensor.

[0160] Example 22: The method of any of examples 16 through 21, further comprising a reference electrode at the distal portion of the elongated body, wherein the flex circuit includes a reference electrode trace element electrically coupled to the reference electrode. [0161] Example 23: The method of any of examples 16 through 22, wherein the elongated substrate of the flex circuit splits to form a first substrate distal portion and a second substrate distal portion, and wherein the first substrate distal portion and the second substrate distal portion are configured to be mechanically coupled.

[0162] Example 24: The method of any of examples 16 through 23, where the flex circuit defines a plurality of holes at a proximal portion of the flex circuit, the plurality of holes configured to receive pins of a connector to electrically couple the plurality of trace elements to the connector.

[0163] Example 25: The method of example 24, wherein the connector is configured to interface with the handle.

[0164] Example 26: The method of any of examples 16 through 25, wherein the flex circuit defines at least one twist along a portion of the flex circuit extending between the handle and distal portion of the elongated body.

[0165] Example 27: The method of any of examples 16 through 26, wherein the flex circuit defines a helix along at least a portion of the flex circuit extending between the handle and the distal portion of the elongated body.

[0166] Example 28: The method of any of examples 16 through 27, wherein the plurality of trace elements includes at least nine trace elements.

[0167] Example 29: The method of any of examples 16 through 28, further comprising control circuitry configured to deliver energy between at least some of the plurality of electrodes at a voltage of at least 1500 volts.

[0168] Example 30: The method of any of examples 16 through 29, wherein a distal portion of the flex circuit where the plurality of trace elements are electrically connected to the plurality of electrodes includes a predefined curve.

[0169] Example 31 : A medical system includes a handle; an elongated body; a plurality of electrodes at a distal portion of the elongated body; a flex circuit extending at least between the handle and the distal portion of the elongated body, the flex circuit including: an elongated substrate defining at least a first face and a second face, and a plurality of trace elements disposed on the elongated substrate, each of the plurality of trace elements electrically connected to at least one electrode of the plurality of electrodes, wherein a first group of trace elements of the plurality of trace elements is disposed on the first face of the elongated substrate, the first group of trace elements electrically connected to a first group of electrodes of the plurality of electrodes, wherein a second group of trace elements of the plurality of trace elements is disposed on the second face of the elongated substrate opposite the first face, the second group of trace elements electrically connected to a second group of electrodes the plurality of electrodes, wherein a third group of trace elements of the plurality of trace elements is disposed on the first face of the elongated substrate, the third group of trace elements electrically connected to a third group of electrodes of the plurality of electrodes, and wherein a fourth group of trace elements of the plurality of trace elements is disposed on the second face of the elongated substrate, the fourth group of trace elements electrically connected to a fourth group of electrodes of the plurality of electrodes; and control circuitry electrically connected to the plurality of electrodes via the plurality of trace elements and configured to control the plurality of electrodes to deliver energy to tissue of a patient, wherein the control circuitry is configured to activate the first group of electrodes and the second group of electrodes for a first time period, wherein the control circuitry is configured to activate the third group of electrodes and the fourth group of electrodes for a second time period different than the first time period, wherein, when activated by the control circuitry for the first time period, the first group of electrodes and the second group of electrodes have a different polarity, and wherein, when activated by the control circuitry for the second time period, the third group of electrodes and the fourth group of electrodes have a different polarity.

[0170] Example 32: The medical system of example 31, wherein the first group of trace elements and the second group of trace elements are disposed on a first lateral side of the elongated substrate, and wherein the third group of trace elements and the fourth group of trace elements are disposed on a second lateral side of the elongated substrate opposite the first lateral side.

[0171] Various examples of the disclosure have been described. These and other examples are within the scope of the following claims.

Claims

WHAT IS CLAIMED IS:

1. A medical system comprising: a handle; an elongated body; a plurality of electrodes at a distal portion of the elongated body; and a flex circuit extending at least between the handle and the distal portion of the elongated body, the flex circuit including: an elongated substrate defining at least a first face and a second face opposite the first face; and a plurality of trace elements disposed on the elongated substrate, each of the plurality of trace elements electrically connected to at least one electrode of the plurality of electrodes, wherein a first group of trace elements of the plurality of trace elements is disposed on the first face of the elongated substrate, the first group of trace elements electrically connected to a first group of electrodes of the plurality of electrodes, wherein a second group of trace elements of the plurality of trace elements is disposed on the second face of the elongated substrate, the second group of trace elements electrically connected to a second group of electrodes the plurality of electrodes, and wherein, when activated, the first group of electrodes and the second group of electrodes have a different polarity.

2. The medical system of claim 1, further comprising control circuitry, wherein a third group of trace elements of the plurality of trace elements is disposed on the first face of the elongated substrate, the third group of trace elements electrically connected to a third group of electrodes of the plurality of electrodes, wherein a fourth group of trace elements of the plurality of trace elements is disposed on the second face of the elongated substrate, the fourth group of trace elements electrically connected to a fourth group of electrodes of the plurality of electrodes, wherein the control circuitry is configured to activate the first group of electrodes and the second group of electrodes for a first time period, and wherein the control circuitry is configured to activate the third group of electrodes and the fourth group of electrodes for a second time period different than the first time period, wherein, when activated, the third group of electrodes and the fourth group of electrodes have a different polarity.

3. The medical system of claim 2, wherein the first group of trace elements and the second group of trace elements are disposed on a first lateral side of the elongated substrate, and wherein the third group of trace elements and the fourth group of trace elements are disposed on a second lateral side of the elongated substrate opposite the first lateral side.

4. The medical system of any of claims 2 and 3, wherein laterally adjacent trace elements of the plurality of trace elements are spaced apart by at least a first lateral distance, and wherein the first group of trace elements and the second group of trace elements are spaced apart from the third group of trace elements and the fourth group of trace elements by at least a second lateral distance, the second lateral distance being greater than the first lateral distance.

5. The medical system of claim 4, where the first lateral distance is at least about 0.0040 inches, and wherein the second lateral distance is at least about 0.0060 inches.

6. The medical system of any of claims 1 through 5, further comprising one or more sensors at the distal portion of the elongated body, wherein the flex circuit includes one or more sensor trace elements disposed on the elongated substrate and electrically coupled to the one or more sensors, and wherein the one or more sensors include a temperature sensor or a position sensor.

7. The medical system of any of claims 1 through 6, further comprising a reference electrode at the distal portion of the elongated body, wherein the flex circuit includes a reference electrode trace element electrically coupled to the reference electrode.

8. The medical system of any of claims 1 through 7, wherein the elongated substrate of the flex circuit splits to form a first substrate distal portion and a second substrate distal portion, and wherein the first substrate distal portion and the second substrate distal portion are configured to be mechanically coupled.

9. The medical system of any of claims 1 through 8, where the flex circuit defines a plurality of holes at a proximal portion of the flex circuit, the plurality of holes configured to receive pins of a connector to electrically couple the plurality of trace elements to the connector.

10. The medical system of claim 9, wherein the connector is configured to interface with the handle.

11. The medical system of any of claims 1 through 10, wherein the flex circuit defines at least one twist along a portion of the flex circuit extending between the handle and distal portion of the elongated body.

12. The medical system of any of claims 1 through 11, wherein the flex circuit defines a helix along at least a portion of the flex circuit extending between the handle and the distal portion of the elongated body.

13. The medical system of any of claims 1 through 12, wherein the plurality of trace elements includes at least nine trace elements.

14. The medical system of any of claims 1 through 13, further comprising control circuitry configured to deliver energy between at least some of the plurality of electrodes at a voltage of at least 1500 volts.

15. The medical system of any of claims 1 through 14, wherein a distal portion of the flex circuit where the plurality of trace elements are electrically connected to the plurality of electrodes includes a predefined curve.