RU2574369C2 - Catheter display unit presenting inclination and pressure - Google Patents

Abstract

FIELD: medicine.

SUBSTANCE: group of inventions refers to medicine. A method for information presentation is implemented by means of a medical procedure device. The device comprises a processor unit and a display enabling an operator to monitor an invasive probe inside the individual's body. The processor unit is configured connected to the invasive probe to receive probe measurements and display a measurement icon on the display. That enables generating the probe parameters related to the invasive probe inside the individual's body. The parameters consist of a probe curvature angle and pressure. A measurement-specific icon enabling the operator to monitor both the probe curvature angle, and pressure is presented on the display.

EFFECT: providing more accurate positioning of the invasive prove, and making the probe-assisted diagnostic and/or therapeutic procedures effective and safe.

17 cl, 3 dwg

Description

FIELD OF TECHNOLOGY

The present invention generally relates to invasive medical devices and, in particular, to methods and devices for displaying the characteristics of a probe, such as a catheter, inside a patient's body.

BACKGROUND OF THE INVENTION

In some diagnostic and therapeutic methods, a catheter is inserted into the heart cavity and brought into contact with the inner wall of the heart. In such procedures, it is generally important that the distal tip of the catheter grips the endocardium with sufficient pressure to provide good contact. Excessive pressure, however, can cause unwanted damage to heart tissue and even perforation of the heart wall.

For example, in intracardiac radiofrequency (RF) ablation, a catheter having an electrode at the distal end is inserted through the patient’s cardiovascular system into the heart cavity. The electrode is brought into contact with the site (or sites) of the endocardium, and RF energy is applied through a catheter to the electrode to ablate the heart tissue in this area. Proper contact between the electrode and the endocardium during ablation is required to achieve the desired therapeutic effect without undue tissue damage.

A number of patent publications describe catheters with integrated pressure sensors for detecting tissue contact. As one example, US Patent Application Publication No. 2007/0100332, which is incorporated herein by reference, describes systems and methods for evaluating the intensity of electrode-tissue contact for tissue ablation. An electromechanical sensor inside the catheter shaft generates electrical signals corresponding to the number of electrode motions within the distal section of the catheter shaft. The data output device receives electrical signals to estimate the level of contact between the electrode and the tissue.

As another example, US Pat. No. 6,695,808, which is incorporated herein by reference, describes an apparatus for treating selected patient tissue or region of an organ. The probe has a contact surface that can be aimed at the area, thereby creating contact pressure. A pressure transmitter measures contact pressure. It is believed that this design satisfies the needs of procedures in which a medical instrument needs to be brought into tight, but not excessive contact with the anatomical surface by providing the tool user with information that is an indicator of the presence and magnitude of the contact force.

Other pressure catheters are described in US Pat. No. 6,241,724 and US Pat. No. 6,915,149, the disclosures of which are incorporated herein by reference.

PCT International Publication WO 2007/067938, the disclosure of which is incorporated herein by reference, describes a method for displaying an electrode contact with a catheter tissue in an electro-anatomical mapping and navigation system. This system provides an indication to a physician regarding the electrical interaction of an electrode, such as an ablation electrode or a mapping electrode, with a patient. The indication may be provided by changing the color or other displayed characteristics of the electrode on the screen of the navigation system or by presenting an oscillating signal showing the connection of the electrode. This method of providing information about the connection of the electrode is considered the least distracting to the attention of the doctor.

SUMMARY OF THE INVENTION

The embodiments of the present invention described below provide new means and methods for displaying parameters related to the quality of capture by an invasive probe of tissue within the body of an object. This type of display can assist the operator of the probe in visual observation of the situation for the given probe and, thus, in ensuring the efficiency and safety of diagnostic and / or therapeutic procedures carried out using this probe.

An embodiment of the present invention provides a method for displaying information. This method includes obtaining a measurement with respect to an invasive probe within the body of an object of at least one probe parameter selected from a group of parameters consisting of the bending angle of the probe and pressure on the probe. According to the measurement, an icon representing at least one probe parameter for operator observation of the probe is displayed on the display screen.

In some embodiments, the probe includes a distal tip that bends in the resilient joint, and obtaining a measurement includes measuring the strain of the joint due to engagement of tissue in the body with the distal end. In the disclosed embodiment, the probe comprises a catheter that is inserted into the heart cavity of the object and captures the tissue of the heart muscle. This method may include the application of energy through the distal end for ablation of tissue of the heart muscle, and the operator controls the application of energy in accordance with the icon. Additionally or alternatively, the measurement of strain includes the recognition of both the strain of the joint and the position of the probe within the body by transmitting and receiving one or more magnetic fields.

Typically, displaying an icon includes placing an icon on a display screen to represent the location of the probe within the body. The placement of the icon may include the location of the icon on the display screen relative to the surface map of the organ of the body, and the measurement includes the measurement of pressure between the probe and surface.

In the disclosed embodiment, the display of the icon includes a representation of the icon to show both the bending angle and pressure, the icon being rotated to show the bending angle, and coloring to represent the pressure.

Also, in accordance with an embodiment of the present invention, there is provided a device for performing a medical procedure comprising a display screen arranged for the operator to observe an invasive probe inside the body of an object. A processor is connected to obtain a measurement with respect to the invasive probe of at least one probe parameter selected from the group of parameters consisting of the bend angle of the probe and pressure on the probe, and to display an icon corresponding to the measurement and representing at least one probe parameter.

Additionally provided is, in accordance with an embodiment of the present invention, a computer program product comprising a computer-readable medium on which program instructions are stored that, when read by a computer, initiate a computer acquiring a measurement with respect to an invasive probe within the body of the at least one a probe parameter selected from a group of parameters consisting of a bending angle of the probe and pressure on the probe, and displaying, as measured, on the display screen and Onka representing at least one probe parameter for observation probe operator.

The present invention will be better understood from the following detailed description of its embodiments along with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

figure 1 is a schematic graphical illustration of a medical system based on the use of a catheter in accordance with an embodiment of the present invention;

FIG. 2 is a schematic detailed view showing a distal tip of a catheter in contact with intracardiac tissue, in accordance with an embodiment of the present invention; and

3 is a schematic illustration of a display screen, including an icon corresponding to the tip of a catheter, in accordance with an embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Figure 1 is a schematic graphical illustration of a system 20 for cardiac catheterization in accordance with an embodiment of the present invention. System 20 may be based, for example, on a CARTO ™ system from Biosense Webster Inc. (Diamond Bar, California). This system comprises an invasive probe in the form of a catheter 28 and a control panel 34. In the embodiment described below, it is assumed that the catheter 28 is used for ablation of intracardiac tissue, as is known in the art. Alternatively, a catheter can be used to accommodate necessary changes for other therapeutic and / or diagnostic purposes in the heart or other organs of the body.

An operator 26, such as a cardiologist, introduces a catheter 28 through the cardiovascular system of the patient 24 so that the distal end 30 of the catheter enters the heart cavity 22 of the patient. The operator advances the catheter so that the distal tip of the catheter grabs the intracardiac tissue at the desired point or points. The catheter 28 is usually connected to the console 34 via a suitable connector at its proximal end. The remote control 34 includes a radio frequency (RF) generator 40 that delivers high-frequency electrical energy through a catheter to ablate tissue in the heart to areas captured by the distal tip, as described below. Alternatively, the catheter and system can be configured to perform ablation using other techniques that are known in the art, such as cryo-ablation. Also, as an alternative or in addition, the catheter and system can be used to perform other types of therapeutic and / or diagnostic procedures, such as electro-anatomical mapping.

The remote control 34 uses positional recognition technology to determine the location coordinates of the distal end 30 of the catheter 28 within the heart 22. In the present embodiment, it is assumed that the remote control uses magnetic positional recognition, which is also used in bend angle and pressure data with respect to the distal end, as described below . Additionally or alternatively, the principles of the present invention can be applied using other techniques of positional recognition and pressure measurement, as is known from the prior art.

For the purpose of magnetic position recognition, the driver circuit 38 in the remote control 34 starts field generators 32 that create magnetic fields inside the patient’s body 24. Typically, the field generators contain coils that are located in the lower part of the patient’s body at known points externally on the patient. These coils generate magnetic fields in a predetermined working volume that holds the heart 22. A magnetic field sensor inside the distal end 30 of the catheter 28 (not shown in the drawings) generates electrical signals in response to these magnetic fields. The signal processor 36 processes these signals in order to determine the coordinates of the location of the distal end, usually including the coordinates and location, and orientation. This position recognition method is implemented in the aforementioned CARTO system and is described in detail in US Pat. A1 and 2004/0068178 A1, the descriptions of which are incorporated into this description by reference.

The processor 36 typically comprises a general purpose computer with a suitable data preprocessor and interface circuits for receiving signals from the catheter 28 and controlling other components of the console 34. The processor can be programmed using the software to perform the functions described in this description. The software may be downloaded to the console 34 electronically, via a network, for example, or it may be provided on physical media such as optical, magnetic or electronic storage media. Alternatively, some or all of the functions of the processor 36 may be performed by specialized or programmable digital hardware components of the system.

Based on the signals received from the catheter 28 and other components of the system 20, the processor 36 triggers the display 42 to provide the operator 26 with visual feedback regarding the distal end 30 of the catheter 28 in the patient’s body, as well as status and remote control information regarding the current procedure . Visual responses indicate pressure at the distal end, as well as the bending angle of the distal tip of the catheter, as described below with reference to FIG.

Additionally or alternatively, system 20 may include an automated mechanism for maneuvering and manipulating the catheter 28 within the patient’s body 24. Such mechanisms are typically capable of controlling both the longitudinal movement (forward / backward) of the catheter and the lateral movement (deflection / rotation) of the distal end of the catheter . Some mechanisms of this type use direct current magnetic fields for this purpose, for example. In such embodiments, the processor 36 generates a control input signal to control the movement of the catheter based on the signals from the magnetic field sensor in the catheter. As noted above, these signals are indicative of both the position of the distal end of the catheter and the force acting on the distal end. In this case, the pressure and bending angle shown on the display 42 can be used by a human operator to monitor the status and progress of the automated procedure.

Figure 2 is a schematic view of the cavity of the heart 22, given in section and showing the distal end 30 of the catheter 28 inside the heart, in accordance with an embodiment of the present invention. The catheter contains an insertion portion 60, which is usually inserted percutaneously into the heart through a blood vessel such as a vena cava or aorta. The electrode 50 on the distal tip 52 of the catheter captures the intracardiac tissue 70. The pressure of the distal tip acting on the endocardium locally deforms the intracardiac tissue so that the electrode 50 contacts a relatively large area of tissue. In the illustrated example, the electrode captures the endocardium not so much directly as at an angle. The distal tip 52 thus bends in the elastic joint 56 relative to the distal end of the catheter insertion portion 60. Bending can promote optimal contact between the electrode and intracardiac tissue.

Due to the elastic properties of the joint 56, the bending angle and the axial displacement of the joint are proportional to the pressure acting from the side of the fabric 70 on the distal tip 52 (or, equivalently, the pressure acting from the side of the distal tip to the fabric). The measurement of the deformation of the joint, in terms of bending angle and axial displacement, thus gives a designation of this pressure. The pressure designation may be used by operator 26 of system 20 to ensure that the distal tip presses on the endocardium tightly enough to produce the desired therapeutic or diagnostic result, but not so much as to cause unwanted tissue damage.

A variety of techniques can be used in measuring the bending angle and pressure acting on the distal tip 52. Components and methods that can be used for this purpose are described, for example, in patent application US 11/868733, registered October 8, 2007, the right to which is assigned to the patent holder of this patent application, and a description of which is incorporated into this description by reference. This patent application describes a catheter whose distal tip connects to the distal end of the catheter insertion via a spring-loaded connection (such as connection 56) that deforms in response to pressure acting on the distal tip when it grabs tissue. The magnetic position recognition unit inside the probe, containing coils on opposite sides of the connection, recognizes the position of the distal tip relative to the distal end of the input portion. A change in this relative position is an indication of the deformation of the spring and, thus, gives a designation of pressure.

Compound 56 may comprise a superelastic connecting member as described in US Patent Application 12/134592, filed June 6, 2008. Alternatively, the connecting member may include a coil spring or any other suitable type of elastic component with the necessary flexibility and strength characteristics . U.S. Patent Application 12/327226, filed December 3, 2008, describes the arrangement of magnetic coils inside the distal end of a catheter, which can be used to recognize tip angle and pressure with increased accuracy. The right to both of these patent applications is assigned to the patent holder of this patent application, and they are incorporated into this description by reference.

FIG. 3 is a schematic diagram of a cardiac cavity card 80 that includes an icon 84 corresponding to the distal end 30 of a catheter 28, in accordance with an embodiment of the present invention. A card of this type is usually presented on the display 42 as an aid to the operator 26 in visualizing the distal end of the catheter within the heart 22. The card includes a graphical representation of the inner surface 82 of the heart cavity in which the distal end of the catheter is located. (The surface 82 can be completely reconstructed, as shown in FIG. 3, or only partially.) The position of the icon 84 relative to the surface 82 gives the operator the location of the present distal end of the catheter in the heart cavity.

Icon 84 shows not only the location of the distal end 30, but also angle and pressure characteristics. In the example of FIG. 3, the icon is rotatable to show the measured bending angle of the distal tip 52 relative to the input portion 60. If the operator sees that the distal tip of the catheter is bent at an acute angle, for example, he or she can reconfigure the position of the catheter before how to continue a diagnostic or therapeutic procedure, such as ablation of heart tissue.

In addition, at least a portion 86 of the icon may be colored (in the drawing, represented by hatching) to indicate pressure. For example, staining in green can mean that the pressure is in the range corresponding to RF ablation, while red can mean too high a pressure and blue can be too low. Pressure ranges can be set in advance or they can be adjusted by the operator. In any case, the operator then applies RF energy only when the pressure is within the range, which will give the desired therapeutic result.

The graphical display of pressure and bending angle by means of the icon 84 gives the operator additional visual information, which is not provided for by display techniques known in the art. This additional information may be useful as a supplement or instead of measuring the electrode / tissue electrical contact resistance. The display of pressure and / or angle itself is important, for example, in the following circumstances:

- In contact with the scarred heart muscle, the electrical contact resistance will not reflect the pressure with accuracy, and therefore direct pressure measurement is required.

- When the catheter touches the heart wall from the side (along the length of the catheter), the electrical contact resistance can be low, since the contact area is large, even if the pressure acting on the heart wall from the side of the catheter is small. The pressure and angle display, as shown in figure 3, allows the operator to identify and correct situations of this type.

- Similarly, when the catheter touches the trabecular wall, the electrical contact resistance can be low even if slight or zero pressure is applied. Direct pressure measurement also enables the operator to identify and correct situations of this type.

Although the icon 84 in FIG. 3 represents the parameters of both the tip bending angle and pressure, in addition to the location of the catheter tip, the examples described above show that it may be useful to display either the angle or pressure separately. Additionally or alternatively, angle measurement and pressure measurement — both or one of them — can be displayed together with electrical contact resistance measurements or other parameters. Moreover, although FIG. 3 shows a particular case of the graphical presentation mode, other techniques for displaying angle and pressure data will be apparent to those skilled in the art and will be considered within the scope of the present invention. The imaging techniques that are described or proposed above can be applied not only to cardiac catheterization procedures, but also to invasive diagnostic and therapeutic methods for using other types.

Thus, it will be appreciated that the embodiments described above are given by way of example and that the present invention is not limited to what has been, in particular, shown and described above. More specifically, the scope of the present invention includes both combinations and parts of combinations of various features described above, as well as their variations and modifications that may occur to specialists in this field after reading the foregoing description and which are not disclosed in the prior art.

Claims (17)

1. A method of displaying information, including the steps in which:
receive, in relation to the invasive probe inside the body of the object, measuring the parameters of the probe, consisting of the bending angle of the probe and pressure on the probe; and
in accordance with the measurements, an icon is displayed on the display screen representing, for observation by the probe operator, both the bending angle of the probe and the pressure on the probe. 2. The method according to claim 1, in which the probe comprises a distal tip, bending in an elastic connection, and in which the step of obtaining a measurement includes measuring the deformation of the connection due to engagement of tissue in the body with a distal tip. 3. The method according to p. 2, in which the probe contains a catheter that is inserted into the heart cavity of the object and captures the tissue of the heart muscle. 4. The method according to p. 3, further comprising the step of applying energy through the distal tip to ablate the tissue of the heart muscle, while the operator controls the application of energy in accordance with the icon. 5. The method of claim 2, wherein the step of measuring the strain includes recognizing both the strain of the joint and the position of the probe within the body by transmitting and receiving one or more magnetic fields. 6. The method according to claim 1, wherein the step of displaying the icon comprises placing the icon on the display screen to represent the location of the probe within the body. 7. The method according to claim 6, in which the stage of placing the icon includes the location of the icon on the display screen relative to the map of the surface of the body organ and in which the step of obtaining a measurement comprises measuring the pressure between the probe and the surface. 8. The method of claim 1, wherein the icon is rotatable to show a bending angle and coloring to represent pressure. 9. A device for conducting a medical procedure, comprising:
a display screen for the operator to monitor the invasive probe inside the body of the object; and
a processor configured to connect to the invasive probe to obtain measurements with respect to the invasive probe, probe parameters consisting of the bend angle of the probe and pressure on the probe, and to display on the display screen an icon corresponding to the measurements and representing both the bend angle and the pressure on the probe . 10. The device according to claim 9, further comprising an invasive probe, the probe including a distal tip bending in an elastic joint, and the processor is configured to measure the strain of the joint due to meshing of the tissue in the body by the distal tip. 11. The device according to p. 10, in which the probe contains a catheter for insertion into the heart cavity of an object in order to capture tissue of the heart muscle. 12. The device according to claim 11, in which the catheter is configured to apply energy through the distal tip to ablate the tissue of the heart muscle, while the operator controls the application of energy in accordance with the icon. 13. The device according to p. 10, further comprising at least one magnetic field generator for creating a magnetic field near the probe, in which the processor is configured to measure both the deformation of the connection and the position of the probe inside the body, in accordance with the magnetic field. 14. The device according to claim 9, in which the processor is configured to place an icon on the display screen to represent the location of the probe inside the body. 15. The device according to p. 14, in which the processor is configured to create a map of the surface of the organ of the body, the location of the icons on the display screen relative to the map and measuring pressure between the probe and the surface. 16. The device according to claim 9, in which the icon is rotatable to show the angle of bending and coloring to represent pressure. 17. A machine-readable medium on which program instructions are stored which, when read by a computer, initiate the computer receiving measurements with respect to the invasive probe inside the body of the object, consisting of the bending angle of the probe and pressure on the probe, and displaying, in accordance with the measurements, on the display screen icons representing for the operator to observe both the bending angle and the pressure of the invasive probe.

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