Distal end assembly guidance

Abstract

To provide a catheter alignment system. [Solution] In one embodiment, the catheter alignment system includes a catheter inserted into a body site, the catheter having catheter electrodes for contacting tissue at each position within the body site, a display, and a processing circuit for receiving signals provided by the catheter, evaluating in response to the received signals the respective levels of contact between some of the catheter electrodes and the tissue of the body site, finding a direction in which the catheter should be moved in order to improve at least one of the respective contact levels of at least one of the catheter electrodes in response to each of the contact levels of some of the catheter electrodes, and rendering on the display a representation of the catheter in response to the received signals and a directional indicator indicating the direction in which the catheter should be moved in response to the found direction.

Description

Technical Field

[0001] The present invention relates to medical devices, and more particularly, without limitation, to a catheter having an expandable distal assembly.

Background Art

[0002] A wide range of medical procedures involve placing a probe, such as a catheter, inside a patient's body. To track such probes, position sensing systems have been developed. Magnetic position sensing is one of the known methods in the art. In magnetic position sensing, a magnetic field generator is typically placed at a known position outside the patient. Magnetic field sensors within the distal end of the probe generate electrical signals in response to these magnetic fields, and these signals are processed to determine the coordinate position of the distal end of the probe. These methods and systems are described in U.S. Pat. Nos. 5,391,199, 6,690,963, 6,484,118, 6,239,724, 6,618,612, and 6,332,089, International Publication No. 1996 / 005768, and U.S. Patent Application Publication Nos. 2002 / 0065455, 2003 / 0120150, and 2004 / 0068178, the disclosures of which are hereby incorporated by reference in their entirety (see also the appendix of provisional patent application No. 63 / 129,475, filed prior to the filing date of Dec. 22, 2020). Position may also be tracked using impedance or current-based systems.

[0003] One medical procedure in which these types of probes or catheters have proven to be extremely useful is in the treatment of cardiac arrhythmias. Cardiac arrhythmias, and particularly atrial fibrillation, continue to be a common and dangerous medical condition, especially in the elderly population.

[0004] The diagnosis and treatment of cardiac arrhythmias involve mapping the electrical properties of cardiac tissue, particularly the endocardium and cardiac volume, and selectively ablating the cardiac tissue by applying energy. Such ablation can stop or modify the propagation of unwanted electrical signals from one part of the heart to another. The ablation process destroys unwanted electrical pathways by forming non-conductive damaged areas. Various modes of energy delivery have been disclosed to date for the purpose of forming damaged areas, including the use of microwaves, lasers, and more generally, radiofrequency energy to create conduction blocks along the cardiac tissue walls. In a two-step procedure that involves mapping followed by ablation, a catheter containing one or more electrical sensors is typically advanced into the heart, and data is obtained at multiple points, thereby sensing and measuring electrical activity at each point within the heart. These data are then used to select the target region of the endocardium to be ablated.

[0005] Electrode catheters have been commonly used in medical practice for many years. They are used to stimulate and map electrical activity within the heart and to ablate areas exhibiting abnormal electrical activity. During use, the electrode catheter is inserted into a major vein or artery, such as the femoral artery, and then guided into the target cardiac chamber. A typical ablation procedure involves inserting a catheter with one or more electrodes at its distal end into the cardiac chamber. A reference electrode can be provided, typically by being taped to the patient's skin or by a second catheter positioned within or near the heart. A radio frequency (RF) current is applied to the tip electrode of the ablation catheter, causing the current to flow through the surrounding medium, i.e., blood and tissue, toward the reference electrode. The distribution of the current depends on the amount of electrode surface in contact with tissue, compared to blood, which has higher conductivity than tissue. Tissue heating occurs due to the electrical resistance of the tissue. When tissue is sufficiently heated, it causes cell destruction in the cardiac tissue, resulting in the formation of non-conductive damaged areas within the cardiac tissue.

[0006] Therefore, when an ablation catheter or other catheter is placed in the body, particularly near endocardial tissue, it is desirable that the distal tip of the catheter be in direct contact with the tissue. This contact can be confirmed, for example, by measuring the contact between the distal tip and the body tissue. U.S. Patent Applications Publications 2007 / 0100332, 2009 / 0093806, and 2009 / 0138007 (see also Appendix to Priority Provisional Patent Application 63 / 129,475 filed December 22, 2020), whose disclosures are incorporated herein by reference, describe a method for sensing the contact pressure between the distal tip of a catheter and the tissue in a body cavity using a force sensor embedded in the catheter.

[0007] Several references, including U.S. Patent Nos. 5,935,079, 5,891,095, 5,836,990, 5,836,874, 5,673,704, 5,662,108, 5,469,857, 5,447,529, 5,341,807, 5,078,714, and Canadian Patent Application No. 2,285,342, report methods for determining contact between an electrode and tissue. Some of these references, for example, U.S. Patents 5,935,079, 5,836,990, and 5,447,529, determine contact between an electrode and tissue by measuring the impedance between the tip electrode and the return electrode. As disclosed in Patent No. 529, it is generally known that the impedance through blood is lower than the impedance through tissue. Therefore, tissue contact is detected by comparing the total impedance value of a pair of electrodes with pre-measured impedance values ​​when one electrode is known to be in contact with tissue and when one electrode is known to be in contact with blood only.

[0008] U.S. Patent No. 9,168004 to Glianer, incorporated herein by reference (see also Appendix to Priority Provisional Patent Application No. 63 / 129,475 filed December 22, 2020), describes the use of machine learning to determine catheter electrode contact. Patent No. 9,168004 describes a cardiac catheterization procedure performed by the steps of: storing an indication of the contact state between an electrode of a probe and the wall of the heart as either a contact state or a non-contact state; making a series of determinations of the impedance phase angle of the current flowing between this electrode and another electrode; identifying the maximum and minimum phase angles in the series of determinations; and defining a binary classifier as an intermediate value between extreme values. The test value is compared to a classifier such that it is adjusted by a hysteresis coefficient, and if the test value is greater than or less than the adjusted classifier, a change in a given state is reported.

[0009] Mest's U.S. Patent Application Publication No. 2013 / 0085416, incorporated herein by reference (see also Appendix to Priority Provisional Patent Application No. 63 / 129,475 filed December 22, 2020), describes a method for in vivo recalibration of force-sensing probes, such as electrophysiological catheters, that provide automatic zero-point zone generation. The distal tip of the catheter or other probe is placed in the patient's body cavity. Verification of the absence of tissue contact is performed using electrocardiogram (ECG) or impedance data, fluoroscopy or other real-time imaging data and / or an electronic anatomical mapping system. Once the absence of tissue contact is verified, the system recalibrates the signal emitted from the force sensor by setting it to correspond to a zero-gram force reading, and this recalibrated baseline reading is used to generate and display force readings based on force sensor data. [Overview of the Initiative] [Means for solving the problem]

[0010] A further embodiment of the present disclosure provides a catheter alignment system comprising: a catheter configured to be inserted into a body part of a living organism, and comprising catheter electrodes configured to contact tissue at each location within the body part; a display; and a processing circuit configured to receive signals provided by the catheter; evaluate, in response to the received signals, the respective contact levels between some of the catheter electrodes and tissue of the body part; find a direction in which the catheter should be moved to improve at least one of the respective contact levels of at least one of the catheter electrodes, in response to the respective contact levels of some of the catheter electrodes; and render on the display a representation of the catheter in response to the received signals, and a directional index indicating the direction in which the catheter should be moved in response to the found direction.

[0011] Furthermore, according to one embodiment of the present disclosure, the catheter includes an expandable distal end assembly on which a catheter electrode is located.

[0012] Furthermore, according to one embodiment of the present disclosure, the expandable distal end assembly includes an inflatable balloon having an axis around which the catheter electrode is positioned.

[0013] Furthermore, according to one embodiment of the present disclosure, the expandable distal end assembly includes an axis on which catheter electrodes are arranged, and the representation of the catheter includes a two-dimensional (2D) representation of the expandable distal end assembly, showing all representations of the catheter electrodes arranged around the axis, with each catheter electrode extending from the central region of the 2D representation toward the outer periphery of the 2D representation.

[0014] Furthermore, according to one embodiment of the present disclosure, the representation of the catheter includes a three-dimensional (3D) representation of the catheter, and the processing circuit is configured to render the 3D representation of the catheter to a display such that a directional indicator in 3D space indicates the direction in which the catheter should move within 3D space.

[0015] Furthermore, according to one embodiment of the present disclosure, the processing circuit is configured to calculate the center of mass of several electrode contact levels among the catheter electrodes in response to the respective contact levels and position coordinates of several of the catheter electrodes, and to find the direction in which the catheter should be moved in response to the calculated center of mass of the electrode contact levels.

[0016] Furthermore, according to one embodiment of the present disclosure, the processing circuit is configured to calculate a center of mass based on several positions of the catheter electrodes in response to several position coordinates of the catheter electrodes, and to find a direction in which the catheter should be moved in response to a line extending from the center of mass of the calculated electrode contact level to the center of mass based on the calculated position.

[0017] In addition, according to one embodiment of the present disclosure, each of the contact levels is selected from two contact states, one representing a state of contact with tissue and the other representing a state of non-contact with tissue, and the processing circuit is configured to calculate the center of mass of several electrode contact levels of the catheter electrodes in response to each contact level having the same one of the two contact states.

[0018] Furthermore, according to one embodiment of the present disclosure, each of the contact levels is selected from at least three states of the quality of contact with the tissue, and the processing circuit is configured to calculate the mass centers of several electrode contact levels of the catheter electrodes as the weighted electrode contact level mass centers in response to each contact level.

[0019] Furthermore, according to one embodiment of the present disclosure, each of the contact levels is selected from a respective sliding scale of the quality of contact with the tissue, and the processing circuit is configured to calculate the mass centers of several electrode contact levels of the catheter electrodes as the weighted electrode contact level mass centers in response to each contact level.

[0020] Another embodiment of the present disclosure also provides a catheter alignment method, which includes: inserting a catheter into a cavity of a body part such that the catheter electrodes contact tissue at each location within the body part of a living organism; receiving signals provided by the catheter; evaluating the respective contact levels of some of the catheter electrodes with tissue of the body part in response to the received signals; finding a direction in which the catheter should be moved in response to each contact level of some of the catheter electrodes to improve at least one of each contact level of at least one of the catheter electrodes; and rendering a representation of the catheter in response to the received signals, and a directional index indicating the direction in which the catheter should be moved in response to the found direction, on a display.

[0021] Furthermore, according to one embodiment of the present disclosure, the catheter includes an expandable distal end assembly on which a catheter electrode is located.

[0022] In addition, according to one embodiment of the present disclosure, the expandable distal end assembly includes an inflatable balloon having an axis around which the catheter electrode is positioned.

[0023] Furthermore, according to one embodiment of the present disclosure, the representation of the catheter includes a two-dimensional (2D) representation of the expandable distal end assembly of the catheter, and shows all representations of the catheter electrodes arranged around the axis of the expandable distal end assembly, with each catheter electrode extending from the central region of the 2D representation toward the outer periphery of the 2D representation.

[0024] Furthermore, according to one embodiment of the present disclosure, the representation of the catheter includes a three-dimensional (3D) representation of the catheter, and rendering includes rendering the 3D representation of the catheter on a display in a state where a direction indicator in the 3D space indicates a direction in which the catheter should be moved within the 3D space.

[0025] Still further, according to one embodiment of the present disclosure, the method includes calculating a center of mass of some of the catheter electrodes' electrode contact levels in response to respective contact levels and position coordinates of some of the catheter electrodes, and finding includes finding a direction in which the catheter should be moved in response to the center of mass of the calculated electrode contact levels.

[0026] In addition, according to one embodiment of the present disclosure, the method includes calculating a center of mass based on positions of some of the catheter electrodes in response to the position coordinates of some of the catheter electrodes, and finding includes finding a direction in which the catheter should be moved in response to a line extending from the center of mass of the calculated electrode contact levels to the center of mass based on the calculated positions.

[0027] Furthermore, according to one embodiment of the present disclosure, each of the respective contact levels is selected from each of two states of contact indicating a contact state with tissue and a non-contact state with tissue, and calculating includes calculating a center of mass of some of the catheter electrodes' electrode contact levels in response to each of the respective contact levels having the same one of the two contact states.

[0028] Furthermore, according to one embodiment of the present disclosure, each of the respective contact levels is selected from at least three states of each quality of contact with tissue, and calculating includes calculating a center of mass of some of the catheter electrodes' electrode contact levels as a weighted center of mass of the electrode contact levels in response to the respective contact levels.

[0029] Furthermore, according to one embodiment of the present disclosure, each of the respective contact levels is selected from each sliding scale of the quality of contact with the tissue, and calculating includes calculating the centroid of the electrode contact levels of some of the catheter electrodes as the weighted centroid of the electrode contact levels in response to each of the respective contact levels.

[0030] According to yet another embodiment of the present disclosure, a catheter protection system includes a sheath having a distal end and configured to be inserted into a body part of a living body, and a catheter including a shaft having a distal portion and an expandable distal end assembly disposed distally on the distal portion, the catheter being configured to be inserted through the sheath, the distal portion and the expandable distal end assembly protruding from the sheath into the body part, the catheter including a pusher disposed within the shaft and coupled to the expandable distal end assembly, such that when the pusher is adjusted longitudinally relative to the shaft, the distal end assembly is selectively extended and retracted, a position tracking subsystem configured to track the relative position between the distal portion of the shaft and the distal end of the sheath and to find when the distal portion of the shaft enters the distal end of the sheath in response to the tracked relative position, and a pusher actuator configured to automatically activate the pusher to extend the expandable distal end assembly in response to the distal portion of the shaft entering the distal end of the sheath.

[0031] In addition, according to one embodiment of the present disclosure, the system includes an audio output device configured to provide an audible warning in response to the distal portion of the shaft entering the distal end of the sheath.

[0032] Furthermore, according to one embodiment of the present disclosure, a position tracking subsystem is configured to detect when the distal portion of the shaft exits the distal end of the sheath in response to a tracked relative position, and a pusher actuator is configured to automatically actuate the pusher to shorten the expandable distal end assembly in response to the distal portion of the shaft exiting the distal end of the sheath.

[0033] Furthermore, according to one embodiment of the present disclosure, the system includes a sound output device configured to provide an audible warning in response to the distal portion of the shaft exiting the distal end of the sheath.

[0034] Furthermore, according to one embodiment of the present disclosure, the position tracking subsystem includes a proximal electrode positioned proximal to an expandable distal end assembly on the distal portion of the shaft, and a surface electrode configured to be attached to the skin surface of a living organism, wherein the position tracking subsystem is configured to track the relative position between the distal portion of the shaft and the distal end of the sheath in response to a measured electrical impedance between the proximal electrode and the surface electrode.

[0035] Furthermore, according to one embodiment of the present disclosure, the position tracking subsystem comprises a generator coil configured to generate magnetic fields having different frequencies in a body part; a first magnetic field sensor located near an expandable distal end assembly in the distal portion of a shaft; and a second magnetic coil sensor located at the distal end of a sheath, wherein the first and second magnetic coil sensors are configured to output their respective electrical signals in response to detecting a magnetic field, and the position tracking subsystem is configured to track the relative position between the distal portion of the shaft and the distal end of the sheath in response to the output electrical signals.

[0036] A catheter protection system is also provided, comprising: a catheter comprising: a sheath having a distal end and configured to be inserted into a body part of a living organism; and a catheter comprising a shaft having a distal portion, with an expandable distal end assembly distally positioned in the distal portion, wherein the catheter is configured to be inserted through the sheath, with the distal portion and the expandable distal end assembly protruding from the sheath into a body part, and the catheter comprising a pusher positioned within the shaft and coupled to the distal end assembly, wherein adjusting the pusher longitudinally relative to the shaft causes the distal end assembly to selectively extend and retract; a position tracking subsystem configured to track the relative position between the distal portion of the shaft and the distal end of the sheath, and to find when the distal portion of the shaft enters the distal end of the sheath in response to the tracked relative position; and an audio output device configured to provide an audible warning in response to the distal portion of the shaft entering the distal end of the sheath.

[0037] Furthermore, according to one embodiment of the present disclosure, a position tracking subsystem is configured to detect when the distal portion of the shaft exits the distal end of the sheath in response to a tracked relative position, and an audio output device is configured to provide an additional audible warning in response to the distal portion of the shaft exiting the distal end of the sheath.

[0038] Furthermore, according to one embodiment of the present disclosure, the position tracking subsystem includes a proximal electrode positioned proximal to an expandable distal end assembly on the distal portion of the shaft, and a body surface electrode configured to be attached to the skin surface of a living organism, wherein the position tracking subsystem is configured to track the relative position of the distal portion and the distal end of the shaft in response to a measured electrical impedance between the proximal electrode and the body surface electrode.

[0039] Furthermore, according to one embodiment of the present disclosure, the position tracking subsystem includes a generator coil configured to generate magnetic fields having different frequencies in a body part, a first magnetic field sensor located near an expandable distal end assembly in the distal portion of a shaft, and a second magnetic coil sensor located at the distal end of a sheath, wherein the first and second magnetic coil sensors are configured to output their respective electrical signals in response to detecting a magnetic field, and the position tracking subsystem is configured to track the relative position between the distal portion of the shaft and the distal end of the sheath in response to the output electrical signals.

[0040] A catheter protection method is also provided, comprising: inserting a sheath into a body part of a living organism; inserting a catheter through the sheath such that the distal portion of the shaft of the catheter and the expandable distal end assembly of the catheter protrude from the sheath into the body part; adjusting a pusher positioned on the shaft and coupled to the expandable distal end assembly longitudinally with respect to the shaft to selectively extend and shorten the expandable distal end assembly; tracking the relative position of the distal portion of the shaft and the distal end of the sheath; finding when the distal portion of the shaft enters the distal end of the sheath in response to the tracked relative position; and automatically activating the pusher to extend the expandable distal end assembly in response to the distal portion of the shaft entering the distal end of the sheath.

[0041] In addition, according to one embodiment of the present disclosure, the method includes providing an audible warning in response to the distal portion of the shaft entering the distal end of the sheath.

[0042] Furthermore, according to one embodiment of the present disclosure, the method includes: finding when the distal portion of the shaft exits the distal end of the sheath in response to a tracked relative position; and automatically acting a pusher to shorten the expandable distal end assembly in response to the distal portion of the shaft exiting the distal end of the sheath.

[0043] Furthermore, according to one embodiment of the present disclosure, the method includes providing an audible warning in response to the distal portion of the shaft exiting the distal end of the sheath.

[0044] Furthermore, according to one embodiment of the present disclosure, tracking includes tracking the relative position between the distal portion of the shaft and the distal end of the sheath in response to a measured electrical impedance between a proximal electrode positioned proximal to an expandable distal end assembly on the distal portion of the shaft and a body surface electrode attached to the skin surface of a living organism.

[0045] Furthermore, according to one embodiment of the present disclosure, the method includes generating a magnetic field having different frequencies in a body part, and in response to detecting the magnetic field, outputting electrical signals from a first magnetic coil sensor located proximal to an expandable distal end assembly in the distal portion of a shaft and a second magnetic coil sensor located at the distal end of a sheath, respectively, and tracking the relative position between the distal portion of the shaft and the distal end of the sheath in response to the output electrical signals.

[0046] A catheter protection method is also provided, comprising: inserting a sheath into a body part of a living organism; inserting a catheter through the sheath such that the distal portion of the shaft of the catheter and the expandable distal end assembly of the catheter protrude from the sheath into the body part; adjusting a pusher positioned on the shaft and coupled to the expandable distal end assembly longitudinally with respect to the shaft to selectively extend and shorten the expandable distal end assembly; tracking the relative position of the distal portion of the shaft and the distal end of the sheath; finding when the distal portion of the shaft enters the distal end of the sheath in response to the tracked relative position; and providing an audible warning in response to the distal portion of the shaft entering the distal end of the sheath.

[0047] Furthermore, according to one embodiment of the present disclosure, the method includes detecting when the distal portion of the shaft exits the distal end of the sheath in response to a tracked relative position, and providing another audible warning in response to the distal portion of the shaft exiting the distal end of the sheath.

[0048] Furthermore, according to one embodiment of the present disclosure, tracking includes tracking the relative position between the distal portion of the shaft and the distal end of the sheath in response to a measured electrical impedance between a proximal electrode positioned proximal to a distal end assembly expandable to the distal portion of the shaft and a body surface electrode attached to the skin surface of a living organism.

[0049] Furthermore, according to one embodiment of the present disclosure, the method includes generating a magnetic field having different frequencies in a body part, and in response to detecting the magnetic field, outputting electrical signals from a first magnetic coil sensor located proximal to an expandable distal end assembly in the distal portion of the shaft and a second magnetic coil sensor located at the distal end of the sheath, respectively, and tracking the relative position between the distal portion of the shaft and the distal end of the sheath in response to the output electrical signals. [Brief explanation of the drawing]

[0050] The present invention will be understood from the following detailed description in conjunction with the attached drawings. [Figure 1] This is a schematic diagram of a catheter-based position tracking and ablation system according to an embodiment of the present invention. [Figure 2] Figure 1 is a schematic diagram of the balloon catheter used in the system shown. [Figure 3] This is a flowchart including the steps for the balloon alignment method used in the system shown in Figure 1. [Figure 4] Figure 2 is a schematic diagram showing how to find the direction in which to move the balloon catheter. [Figure 5]Figure 2 is a schematic diagram showing the two-dimensional (2D) and three-dimensional (3D) representations of the balloon catheter, as well as the superimposed directional indicators of the 2D and 3D representations. [Figure 6A] Figure 2 shows schematic diagrams of the balloon catheter in its unfolded and folded forms. [Figure 6B] Figure 2 shows schematic diagrams of the balloon catheter in its unfolded and folded forms. [Figure 7] This is a flowchart that includes an example of the steps used in the system shown in Figure 1. [Figure 8A] Figure 2 shows schematic diagrams of the balloon catheter in its deployed and folded states, respectively, placed within a sheath containing a magnetic coil sensor. [Figure 8B] Figure 2 shows schematic diagrams of the balloon catheter in its deployed and folded states, respectively, placed within a sheath containing a magnetic coil sensor. [Figure 9] Figures 8A and 8B are flowcharts showing the steps in a method for tracking the relative positions of the catheter and sheath. [Modes for carrying out the invention]

[0051] Overview Optimal alignment and contact of all active catheter electrodes (e.g., balloon electrodes with pulmonary venous sinuses or any other body part) increases the probability of a successful single-shot ablation. One solution is to provide a diagram of the catheter electrodes showing which electrodes are in good contact with the tissue, using appropriate markings (e.g., highlighting electrodes with sufficient contact). While such a solution guides the physician somewhat on how to improve contact between the electrodes and the tissue, the diagram is not very intuitive regarding the direction of deflection and / or the operational actions that need to be applied to the balloon to improve contact between the catheter electrodes and the tissue.

[0052] Accordingly, embodiments of the present invention solve the above problems by providing a catheter alignment system that evaluates the level of contact between a catheter electrode and tissue of a body part (e.g., a cardiac chamber of a living organism), finds a direction in which the catheter should be moved to improve the contact level of one or more of the catheter electrodes, and renders on a display a representation of the catheter and a directional indicator (e.g., an arrow) indicating the direction in which the catheter should be moved based on the found direction.

[0053] In some embodiments, the representation of the catheter is a two-dimensional (2D) representation showing catheter electrodes arranged around the longitudinal axis of the catheter, with each catheter electrode extending from the central region of the 2D representation toward the outer periphery of the 2D representation.

[0054] In some embodiments, the representation includes a three-dimensional (3D) representation of the catheter, with directional indicators (e.g., arrows) indicating the direction in which the catheter should move in 3D space.

[0055] In some embodiments, the direction in which the catheter should be moved may be calculated based on the "center of mass of the electrode contact level," which may be calculated in response to the position coordinates of the catheter electrode and the evaluated contact level of the catheter electrode.

[0056] In some embodiments, the center of mass at the electrode contact level can be calculated as a weighted center of mass, weighted according to different evaluated contact levels.

[0057] In some embodiments, the evaluated contact level may include two states (e.g., contact, non-contact), or be based on multiple states (e.g., 0, 1, 2), or on a sliding level. For example, if two contact levels are used, the calculation of the "center of mass of the electrode contact level" may be based on whether the electrodes are in contact or not, so that electrodes in contact are given a weight of 1 and electrodes not in contact are given a weight of 0.

[0058] In some embodiments, the direction in which the catheter should be moved can be found in response to a line extending from the center of mass of the calculated electrode contact level to a "position-based center of mass," which is calculated without considering the evaluated contact level.

[0059] When a catheter with an expandable distal end assembly, such as a balloon catheter, is inserted into a body site, the sheath is first inserted into the body site, and the catheter is inserted into the sheath in a folded form. As the distal end assembly advances from the sheath into the body site, it can then be deployed, for example, by inflating an inflatable balloon or expanding a basket. Once the catheter is no longer needed in the body site, the distal end assembly folds up, is retracted into the sheath, and exits the body. In some cases, expandable distal end assemblies include a pusher to help extend and fold the distal end assembly. If the distal end assembly is not folded up before being retracted into the sheath, it may be damaged.

[0060] Accordingly, embodiments of the present invention include a catheter protection system that automatically activates a pusher to extend (fold the distal end assembly) and / or provides an audible warning to a physician when the distal portion of the catheter shaft (proximal to the distal end assembly) is retracted into the distal end of the sheath. The distal portion of the catheter shaft being retracted into the distal end of the sheath can be tracked based on tracking the relative position of the distal end of the sheath and the distal portion of the catheter shaft.

[0061] The relative position of the distal end of the sheath can be tracked using any preferred method. In some embodiments, electrical impedance is used to track the relative position based on the measured electrical impedance between an electrode located on the distal portion of the catheter shaft and a surface electrode attached to the skin surface of the body. The measured electrical impedance increases as the proximal electrode is retracted into the sheath, thereby providing an indicator of the relative position between the distal end of the sheath and the distal end of the shaft. In some embodiments, the distal end of the sheath and the distal portion of the catheter shaft each include their respective position sensors, such as magnetic position sensors. The relative position can then be calculated in response to the signals provided by the position sensors.

[0062] System Description Here, we refer to Figure 1, which is a schematic diagram of a catheter-based position tracking and ablation system 20 according to an embodiment of the present invention. We also refer to Figure 2, which is a schematic diagram of a balloon catheter 40 according to one embodiment of the present invention.

[0063] The position tracking and ablation system 20 is used to determine the position of the balloon catheter 40, which is shown in inset diagram 25 of Figure 1 and in more detail in Figure 2. The balloon catheter 40 includes a shaft 22 and an inflatable balloon 45 attached to the distal end of the shaft 22. The catheter 40 is configured to be inserted into a body part of a living organism. Typically, the balloon catheter 40 is used in therapeutic procedures such as spatial ablation of cardiac tissue in the left atrium.

[0064] The position tracking and ablation system 20 can determine the position and orientation of the shaft 22 of the balloon catheter 40 based on sensing electrodes 52 (a proximal electrode 52a located on the shaft 22 and a distal electrode 52b located at the distal end of the inflatable balloon 45) and a magnetic sensor 50 mounted immediately proximal to the proximal electrode 52a. The proximal electrode 52a, the distal electrode 52b, and the magnetic sensor 50 are connected by wires extending through the shaft 22 to various driver circuits in the console 24. In some embodiments, the distal electrode 52b may be omitted.

[0065] The shaft 22 defines a longitudinal axis 51. A center point 58 on the axis 51 is the origin of the spherical shape of the inflatable balloon 45 and defines the nominal position of the inflatable balloon 45. The catheter 40 includes a plurality of catheter electrodes 55 positioned on the inflatable balloon 45 or on any suitable expandable distal end assembly around the longitudinal axis 51. In some embodiments, the catheter electrodes 55 are positioned around the inflatable balloon 45 and occupy a larger area than the sensing electrodes 52a and 52b. The catheter electrodes 55 are configured to contact tissue at their respective locations within the body part. High-frequency power may be supplied to the catheter electrodes 55 to ablate tissue, such as cardiac tissue.

[0066] Typically, the positioned catheter electrodes 55 are evenly distributed along the equator of the inflatable balloon 45, which is aligned approximately perpendicular to the longitudinal axis 51 of the distal end of the shaft 22.

[0067] The diagram shown in Figure 2 has been selected purely for the purpose of clarifying the concept. Other configurations of the sensing electrode 52 and the catheter electrode 55 are also possible. The magnetic sensor 50 may include additional functions. For clarity, elements not relevant to the disclosed embodiments of the present invention, such as irrigation ports, have been omitted.

[0068] The physician 30 guides the balloon catheter 40 to the target location in the patient's 28 heart 26 by manipulating the shaft 22 using a manipulator 32 near the proximal end of the catheter and / or deflecting it from the sheath 23. While the balloon catheter 40 is inserted into the sheath 23 and the inflatable balloon 45 is deflated, the inflatable balloon 45 inflates and returns to its intended functional shape only after the balloon catheter 40 has retracted from the sheath 23. By housing the balloon catheter 40 in a deflated configuration, the sheath 23 also plays a role in minimizing vascular trauma during its journey to the target location.

[0069] The console 24 includes a processing circuit 41, typically a general-purpose computer, a suitable front end, and an interface circuit 44 that generates signals at and / or receives signals from surface electrodes 49 attached by wires extending through a cable 39 to the chest and back of the patient 28.

[0070] System 20 includes a position tracking subsystem 47 which may include a magnetic sensing subsystem at least partially located within the console 24. The patient 28 is placed in a magnetic field generated by a pad containing a magnetic field generating coil 42, which is driven by a unit 43 located in the console 24. The magnetic field generated by the coil 42 generates a directional signal within a magnetic sensor 50, which is then supplied to a processing circuit 41 as a corresponding electrical input.

[0071] In some embodiments, the processing circuit 41 uses position signals received from the sensing electrode 52 (and / or surface electrode 49), the magnetic sensor 50, and the catheter electrode 55 to estimate the position of the balloon catheter 40 within an organ such as a ventricle. In some embodiments, the processing circuit 41 correlates the position signals received from the electrodes 52, 55 with previously acquired magnetic position calibration position signals to estimate the position of the balloon catheter 40 within the ventricle. The position coordinates of the sensing electrode 52 and the catheter electrode 55 may be determined by the processing circuit 41 based on the impedance or current distribution ratio measured between the electrodes 52, 55 and the surface electrode 49, among other inputs. The console 24 drives a display 27 indicating the distal end of the catheter position within the heart 26.

[0072] Methods of position sensing using current distribution measurements and / or external magnetic fields have various medical applications, such as Biosense Webster. It is implemented in the Carto® system manufactured by Inc. (Irvine, California), and is detailed in U.S. Patents Nos. 5,391,199, 6,690,963, 6,484,118, 6,239,724, 6,618,612, 6,332,089, 7,756,576, 7,869,865, and 7,848,787, International Publication No. 96 / 05768, and U.S. Patent Application Publications 2002 / 0065455(A1), 2003 / 0120150(A1), and 2004 / 0068178(A1).

[0073] The Carto® 3 system applies an impedance-based position tracking method for Active Current Location (ACL). In some embodiments, using the ACL method described above, the processing circuit 41 estimates the positions of the sensing electrode 52 and the catheter electrode 55. In some embodiments, the signals received from electrodes 52 and 55 are correlated with a matrix that maps the impedance (or other electrical value) measured by the sensing electrodes 52 and 55 to positions previously obtained from magnetic position calibration position signals.

[0074] In some embodiments, to visualize catheters that do not include magnetic sensors, the processing circuit 41 may apply an electrical signal-based method called the Independent Current Position (ICL) method. In the ICL method, the processing circuit 41 calculates a local scaling factor for each voxel of a balloon catheter 40 of a certain volume. This factor is determined using a catheter with multiple electrodes having known spatial relationships, such as a lasso-shaped catheter.

[0075] The processing circuit 41 is typically programmed with software to perform the functions described herein. The software can be downloaded electronically to a computer, for example, over a network, or alternatively or additionally, it can be provided and / or stored on a non-temporary physical medium such as magnetic memory, optical memory, or electronic memory.

[0076] Figure 1 shows only the elements relating to the technology of this disclosure for the sake of brevity and clarity. System 20 typically includes additional modules and elements that are intentionally omitted from Figure 1 and the corresponding description because they are not directly related to the technology disclosed. The balloon distal end assembly is described as an example only, and any suitable distal end assembly, such as a basket distal end assembly, may be used instead.

[0077] System 20 may also include a sound output device 48 configured to provide an audible warning, which will be described in more detail with reference to Figure 7.

[0078] Now, referring to Figure 3, this is a flowchart 300 that includes each step in the balloon alignment method for use in the system 20 of Figure 1.

[0079] The processing circuit 41 (Figure 1) is configured to receive signals provided by the catheter 40 (block 302). Signals may be provided from the catheter electrodes 55 to the processing circuit 41, from the body surface electrodes 49 that detect signals provided by the catheter electrodes 55, or directly from a force sensor or temperature sensor. In response to the received signals, the processing circuit 41 is configured to evaluate the respective contact levels between some (some or all) of the catheter electrodes 55 and the tissue of the body part (block 304). In other words, the processing circuit 41 evaluates the contact levels of each of the catheter electrodes 55 or each electrode of a subset of the catheter electrodes 55 (e.g., only the active electrode).

[0080] The contact level may be evaluated based on various methods, including impedance measurements, temperature measurements, force measurements, or pressure measurements, or analysis of IEG traces, as will be described in more detail below.

[0081] Any one of the catheter electrodes 55 may be in full or partial contact with the tissue of the heart 26. In some cases, any one of the catheter electrodes 55 may be in contact with the tissue via another fluid, such as blood of varying concentrations. The level of contact (full or partial contact, or contact via another fluid) of any one of the catheter electrodes 55 with the tissue can be evaluated based on the signal supplied by the catheter 40.

[0082] As used herein and in the claims, the term “contact level” is defined herein as a quantitative indicator of the degree of electrical contact between one of the catheter electrodes 55 and the tissue. As will be described in more detail below, “contact level” can be expressed directly, for example, using measured electrical impedance, or indirectly, for example, using contact force, pressure, or IEGM amplitude (intracardiac electrophysism).

[0083] In some embodiments, the catheter 40 may supply a signal indicating the impedance between the catheter electrode 55 and the body surface electrode 49. Since the impedance indication represents the contact level, a higher impedance value between one of the catheter electrodes 55 and the body surface electrode 49 indicates a higher contact level between that catheter electrode 55 and the tissue. The impedance value can be selected to define the minimum contact level considered to represent sufficient contact between any one of the catheter electrodes 55 and the tissue.

[0084] In some embodiments, the impedance between one of the catheter electrodes 55 on the catheter and another of these electrodes may be used as a measure of the contact level. As disclosed in the '529 patent mentioned in the background art section above, it is known that the impedance through blood is generally lower than the impedance through tissue. Therefore, tissue contact can be assessed by comparing the impedance value of the entire pair of electrodes with a previously measured impedance value when it is known that one electrode is in sufficient contact with tissue and when it is known that one electrode is in contact with blood only.

[0085] In some embodiments, each temperature sensor (e.g., a thermocouple) on the catheter electrode 55 can be used as a measure of the contact level. The temperature sensor on each electrode 55 senses the superposition of the temperature of the irrigation fluid inside the balloon 45 and the temperature of the blood or tissue outside the balloon. The irrigation fluid is cooler than the blood. When the electrode is not in contact with tissue, the blood flow across the surface of the electrode warms the electrode from the outside, and the total temperature sensed by the electrode's temperature sensor becomes higher. When the electrode is in contact with tissue and blood flow is interrupted, the irrigation fluid inside the electrode becomes cooler, and the temperature sensed by the electrode becomes lower. Thus, the temperature values ​​sensed at each electrode 55 can be used as a measure of the contact level.

[0086] In some embodiments, the method of U.S. Patent No. 9,168,004 to Gliner et al., incorporated herein by reference (see also Appendix to Priority Provisional Patent Application No. 63 / 129,475 filed December 22, 2020), may be used for evaluating contact levels using a machine learning-based method.

[0087] In some embodiments, the catheter 40 may be supplied with a signal from a force sensor or a pressure sensor (not shown). The force or pressure indication provides an indication of the contact level, so that a higher force or pressure value indicates a higher level of contact between one of the catheter electrodes 55 and the tissue. The force or pressure value can be selected to define the minimum contact level that is considered to represent sufficient contact between any one of the catheter electrodes 55 and the tissue. These embodiments may use any suitable force or pressure sensor, as well as any suitable method for measuring force or pressure.

[0088] In some embodiments, the generated IEG traces may be used to evaluate the level of contact between one of the catheter electrodes 55 and the tissue. The maximum amplitude of the IEG trace associated with one of the catheter electrodes 55 indicates the level of contact between that catheter electrode 55 and the tissue; therefore, a larger maximum amplitude value of the IEG trace indicates a higher level of contact between that catheter electrode 55 and the tissue. The amplitude values ​​of the IEG traces can be selected to define the minimum contact level that is considered to represent sufficient contact between one of the catheter electrodes and the tissue.

[0089] Each of the contact levels can be selected from two states of contact: contact with tissue and non-contact with tissue. In other words, an electrode can be in one of two states (contact or non-contact), and different electrodes can have different contact states. For example, if the measured value (e.g., impedance, temperature, or force) is lower (or higher) than a given limit, the evaluated contact level may be in contact, and if the measured value is higher (or lower) than a given limit, the evaluated contact level may be in non-contact.

[0090] In some embodiments, each of the contact levels is selected from each of several states (e.g., at least three states) of the quality of contact with the tissue (e.g., no contact, weak contact, strong contact). For example, each state may be associated with a given limit (e.g., impedance, temperature, or force).

[0091] In some embodiments, each of the contact levels is selected from a respective sliding scale of the quality of contact with the tissue. For example, the contact level may be equal to or proportional to a measure of contact such as impedance, temperature, or force.

[0092] Refer to Figure 4, a schematic diagram showing how to find the direction in which the balloon catheter 40 in Figure 2 should be moved. See also Figure 3. Figure 4 shows a schematic diagram of the catheter 40 viewed distal to the distal tip of the inflatable balloon 45 from a point along the longitudinal axis 51 (Figure 2). For simplification, each catheter electrode 55 is labeled (e.g., 1-10). Electrodes 55 whose contact level exceeds a given limit are highlighted with thicker boundaries (e.g., electrodes 1-4 and 9-10). On the other hand, electrodes whose contact level is below a given limit are indicated with thinner boundaries (e.g., electrodes 5-8).

[0093] The processing circuit 41 (Figure 1) is configured to find a direction 400 (for example, a direction toward electrodes 5-8, particularly between electrodes 6 and 7 in the example of Figure 4) in which the catheter 40 should be moved to improve the contact level of one or more catheter electrodes 55, depending on the evaluation level of some or all of the catheter electrodes (for example, electrodes 1-4, 9-10, or all electrodes 55) (block 306).

[0094] In some embodiments, direction 400 can be found by using a pre-entered lookup table that enumerates different combinations of electrodes having contact levels above a given level and corresponding directions typically referenced with respect to the longitudinal axis 51 in order to move the catheter 40. That is, the graphical user interface can instruct the operator to move the balloon "lateral to the longitudinal axis (or central axis) of the balloon" or "towards electrodes 6 and 7" (text or figure).

[0095] In some embodiments, the direction 400 can be found based on calculating the center of mass 402 (e.g., weighted center of mass) at the electrode contact level, which indicates the overall contact direction of the catheter electrode 55. The direction 400 can then be found based on a line 404 connecting the center of mass 402 at the electrode contact level to the center of mass 406 based on the position of the catheter electrode 55. The center of mass 406 based on the position indicates the center of mass of the catheter electrode 55, regardless of the contact level of the individual catheter electrodes 55.

[0096] Therefore, the processing circuit 41 (Figure 1) is configured to calculate the center of mass 402 of some or all electrode contact levels of the catheter electrodes 55 in response to the respective contact levels and position coordinate levels of each catheter electrode 55 (block 308). For example, the center of mass 402 of the electrode contact levels can be calculated as the standard center of mass of any rigid body or main body, weighted according to the contact levels of the catheter electrodes 55 included in the center of mass calculation. The processing circuit 41 is configured to find the direction 400 in which the catheter 40 should be moved in response to the calculated center of mass 402 of the electrode contact levels.

[0097] If each contact level is selected from two contact states, one representing a state of contact with tissue and the other representing a state of non-contact with tissue, the processing circuit 41 is configured to calculate the center of mass 402 of some or all electrode contact levels of the catheter electrode 55 in response to each contact level having the same state of the two contact states (e.g., all electrodes in contact, or all electrodes in non-contact). In other words, the center of mass 402 of the electrode contact levels can be calculated as the center of mass of the catheter electrodes 55 having a contact state (e.g., electrodes 1-4 and 9-10). Alternatively, the center of mass 402 of the electrode contact levels can be calculated as the center of mass of the catheter electrodes 55 having a non-contact state (e.g., electrodes 5-8).

[0098] When each of the contact levels is selected from each of several states (e.g., at least three states) of the quality of contact with the tissue, the processing circuit 41 may be configured to calculate the mass center 402 of some or all of the electrode contact levels of the catheter electrodes 55 as the mass center of the electrode contact levels weighted in response to each contact level and position coordinate of each catheter electrode 55, with greater weighting resulting in higher quality contact of the catheter electrode 55.

[0099] When each of the different levels of contact is selected from the different sliding scales of the quality of contact with the tissue, the processing circuit 41 may be configured to calculate the center of mass 402 of some or all of the electrode contact levels of the catheter electrode 55 as the weighted center of mass of the electrode contact levels in response to each contact level, with greater weighting being given to the catheter electrode 55 for higher quality contact.

[0100] The processing circuit 41 is configured to calculate a line of mass centers 406 based on the positions of some or all of the catheter electrodes 55 in response to the position coordinates of each catheter electrode 55 (i.e., regardless of the contact level of each catheter electrode 55) (block 310). The processing circuit 41 is configured to find the direction 400 in which the catheter 40 should move in response to a line 404 extending from the mass center 402 of the calculated electrode contact level to the mass center 406 based on the calculated position. The orientation of the direction 400 is generally parallel to the line 404 and away from the mass center 402 of the electrode contact level.

[0101] The diagram of catheter 40 in Figure 4 shows a 2D view of catheter 40. The above calculations can be performed to calculate the 3D orientation 400 having orientation in 3D space. For example, the mass center 402 of the electrode contact level, the line 404, and the mass center 406 based on position can be calculated in 3D space based on the 3D position coordinates of catheter electrode 55. The example in Figure 4 is presented with respect to a balloon catheter. The orientation 400 can be calculated for any suitable catheter, such as a basket catheter.

[0102] Now, refer to Figure 5. Figure 5 is a schematic diagram showing the two-dimensional (2D) representation 500 and the three-dimensional (3D) representation 502 of the balloon catheter 40 of Figure 2, and the superimposed directional indicators 504 of the 2D and 3D representations. See also Figure 3.

[0103] The processing circuit 41 (Figure 1) is configured to, in response to a received signal (provided by the catheter 40, which the processing circuit 41 may use to calculate the position coordinates of the catheter 40 and the inflatable balloon 45), render a representation of the catheter 40 (e.g., a 2D representation 500 and / or a 3D representation 502) on the display 27 (Figure 1), as well as superimposed directional indicators 504 indicating the direction to be moved in response to the found direction 400 (Figure 4) (Figure 1).

[0104] The 2D representation 500 is a representation of the expandable distal end assembly (e.g., an inflatable balloon 45) of the catheter 40, showing each representation 506 of the catheter electrodes 55 (Figure 2) arranged around the longitudinal axis of the catheter 40, with each of the catheter electrodes 55 extending from the central region 508 of the 2D representation 500 toward the outer periphery 510 of the 2D representation 500. Each representation 506 of the catheter electrode 55 that is in good contact with the tissue is highlighted with a thicker boundary.

[0105] The 3D representation 502 includes representations 512 of each catheter electrode 55. The processing circuit 41 is configured to render the 3D representation 502 of the catheter 40 to the display 27 (Figure 1) with a 3D spatial directional indicator 504 indicating the direction in which the catheter 40 should be moved in 3D space.

[0106] Next, refer to Figures 6A to 6B, which are schematic diagrams showing the unfolded and folded states of the catheter 40 in Figure 2, respectively. Now, referring to Figure 7, Figure 7 is a flowchart 700 that includes an exemplary step in the method used in the system 20 of Figure 1.

[0107] The sheath 23 has a distal end 600 and is configured to be inserted into a body part 602 of a living organism (e.g., patient 28 in Figure 1) (block 702). The shaft 22 of the catheter 40 has a distal portion 604 and an expandable distal end assembly 606 (e.g., an inflatable balloon 45) positioned distal to the distal portion 604. The catheter 40 is configured to be inserted through the sheath 23 with the distal portion 604 and the expandable distal end assembly 606 protruding from the sheath 23 into the body part 602 (block 704). The catheter 40 includes a pusher 608 positioned within the shaft 22 and coupled to the expandable distal end assembly 606 such that adjusting the pusher 608 longitudinally relative to the shaft 22 selectively extends and shortens the expandable distal end assembly 606.

[0108] The position tracking subsystem 47 (Figure 1) is configured to track the relative position between the distal portion 604 of the shaft 22 and the distal end 600 of the sheath 23 (block 706). In the determination block 708, the position tracking subsystem 47 is configured to determine, in response to the tracked relative position, whether the distal portion 604 is currently within the distal end 600 of the sheath 23. If the distal portion 604 is not currently within the distal end 600 of the sheath 23 (branch 712), the position tracking subsystem 47 is configured to find when the distal portion 604 of the shaft 22 will enter the distal end 600 of the sheath 23 in response to the tracked relative position (block 710). System 20 includes a pusher actuator 610 (block 714) configured to automatically actuate a pusher 608 (on a command from the position tracking subsystem 47) to extend an expandable distal end assembly 606 in response to the distal portion 604 of the shaft 22 entering the distal end 600 of the sheath 23. Additionally or alternatively, an audio output device 48 (Figure 1) is configured to provide an audible alert (on a command from the position tracking subsystem 47) in response to the distal portion 604 of the shaft 22 entering the distal end 600 of the sheath 23.

[0109] If the distal portion 604 is currently at the distal end 600 of the sheath 23 (Block 716), the position tracking subsystem 47 is optionally configured to detect when the distal portion 604 of the shaft 22 leaves the distal end 600 of the sheath 23 in response to the tracked relative position (Block 718). The pusher actuator 610 is optionally configured to automatically actuate the pusher 608 (on a command from the position tracking subsystem 47) to shorten the expandable distal end assembly 606 in response to the distal portion 604 of the shaft 22 leaving the distal end 600 of the sheath 23 (Block 720). Additionally or alternatively, the sound output device 48 is optionally configured to provide an audible warning (on a command from the position tracking subsystem 47) in response to the distal portion 604 of the shaft 22 leaving the distal end 600 of the sheath 23.

[0110] In some embodiments, the position tracking subsystem 47 includes a proximal electrode 52a positioned proximal to an expandable distal end assembly 606 on the distal portion 604 of the shaft 22, and a body surface electrode 49 (Figure 1) configured to be attached to the skin surface of a living organism (e.g., patient 28 in Figure 1). The position tracking subsystem 47 is configured to track the relative position of the distal portion 604 of the shaft 22 and the distal end 600 of the sheath 23 in response to the measured electrical impedance between the proximal electrode 52a and the body surface electrode 49. If the measured electrical impedance between the proximal electrode 52a and the body surface electrode 49 exceeds a given limit, it indicates that the proximal electrode 52a is covered by the sheath 23, and therefore the distal portion 604 of the shaft 22 is either inside or within the sheath 23.

[0111] Refer to Figures 8A and 8B. Figures 8A and 8B are schematic diagrams of the balloon catheter 40 of Figure 2 in its deployed and folded states, respectively, located within a sheath 23 having a magnetic coil sensor 800. Refer to Figure 9. Figure 9 is a flowchart 900 showing the steps in a method for tracking the relative positions of the catheter 40 and the sheath 23 of Figures 8A and 8B.

[0112] The position tracking subsystem 47 (Figure 1) includes a magnetic field generator coil 42 (Figure 1) configured to generate magnetic fields having different frequencies in a body part 602 (block 902), a magnetic coil sensor 50 located proximal to an expandable distal end assembly 606 (e.g., an inflatable balloon 45) in the distal portion 604 of the shaft 22, and a magnetic coil sensor 800 located at the distal end 600 of the sheath 23.

[0113] The magnetic sensor 50 and the magnetic coil sensor 800 are configured to output electrical signals in response to detecting the magnetic field generated by the magnetic field generator coil 42 (block 904). The position tracking subsystem 47 is configured to track the relative position (e.g., distance d in Figure 8A) between the distal portion 604 of the shaft 22 and the distal end 600 of the sheath 23 in response to the output electrical signals (block 906).

[0114] The pusher actuator 610 is configured to automatically actuate the pusher 608 (on a command from the position tracking subsystem 47 in Figure 1) to extend or retract the expandable distal end assembly 606. Additionally or alternatively, an audible output device 48 (Figure 1) is configured to provide an audible warning in response to the tracked relative position between the distal portion 604 and the distal end 600.

[0115] When used herein, the terms “about” or “approximately” with respect to any number or range of numbers indicate a suitable dimensional tolerance that enables a part or set of components to function in accordance with its intended purpose as described herein. More specifically, “about” or “approximately” may refer to a range of values ​​within ±20% of the listed values; for example, “about 90%” may refer to a range of values ​​between 72% and 108%.

[0116] Various features of the present invention are described in the context of separate embodiments for clarity, and these may be provided in combination in a single embodiment. Conversely, various features of the present invention described in the context of a single embodiment for brevity may be provided separately or in any preferred partial combination.

[0117] The embodiments described above are by reference only, and the present invention is not limited to those specifically illustrated and described in the above specification. Rather, the scope of the present invention includes both combinations and partial combinations thereof of the various features described in the above specification, as well as variations and modifications thereof not disclosed in the prior art, which would be conceivable to those skilled in the art by reading the above description.

[0118] [Implementation Method] (1) A catheter alignment system, A catheter configured to be inserted into a body part of a living organism, comprising catheter electrodes configured to contact tissue at various locations within the body part, The display and A processing circuit, Receiving the signal provided by the catheter, In response to the received signal, the contact level between some of the catheter electrodes and the tissue of the body part is evaluated, In response to the respective contact levels of some of the catheter electrodes, to find a direction in which the catheter should be moved in order to improve at least one of the respective contact levels of at least one of the catheter electrodes, A catheter alignment system comprising: a processing circuit configured to render on the display a representation of the catheter in response to the received signal, and a directional indicator indicating the direction in which the catheter should be moved in response to the found direction. (2) The system according to Embodiment 1, wherein the catheter includes an expandable distal end assembly on which the catheter electrode is located. (3) The system according to Embodiment 2, wherein the expandable distal end assembly includes an inflatable balloon having an axis around which the catheter electrode is positioned. (4) The system according to Embodiment 2, wherein the expandable distal end assembly includes an axis around which the catheter electrodes are arranged, and the representation of the catheter includes a two-dimensional (2D) representation of the expandable distal end assembly, showing all representations of the catheter electrodes arranged around the axis, with each of the catheter electrodes extending from the central region of the 2D representation toward the outer periphery of the 2D representation. (5) The system according to Embodiment 1, wherein the representation of the catheter includes a three-dimensional (3D) representation of the catheter, and the processing circuit is configured to render the 3D representation of the catheter to the display such that the direction in which the catheter should move in the 3D space is indicated by the direction indicator in the 3D space.

[0119] (6) The processing circuit In response to the respective contact levels and positional coordinates of some of the catheter electrodes, the center of mass of some of the electrode contact levels of the catheter electrodes is calculated. The system according to Embodiment 1, configured to determine the direction in which the catheter should be moved in response to the center of mass of the calculated electrode contact level. (7) The processing circuit In response to some of the position coordinates of the catheter electrodes, the center of mass based on some of the positions of the catheter electrodes is calculated, The system according to Embodiment 6, configured to determine the direction in which the catheter should be moved in response to a line extending from the center of mass of the calculated electrode contact level to the center of mass based on the calculated position. (8) Each of the above contact levels is selected from two contact states, one representing a state of contact with the tissue and the other representing a state of non-contact with the tissue. The system according to embodiment 6, wherein the processing circuit is configured to calculate the center of mass of some of the electrode contact levels of the catheter electrodes in response to each of the contact levels having the same one of the two contact states. (9) Each of the above contact levels is selected from at least three states of the quality of contact with the tissue, The system according to embodiment 6, wherein the processing circuit is configured to calculate the mass centers of some of the electrode contact levels among the catheter electrodes as weighted electrode contact level mass centers in response to each of the respective contact levels. (10) Each of the respective contact levels is selected from the respective sliding scales of the quality of contact with the tissue, The system according to embodiment 6, wherein the processing circuit is configured to calculate the mass centers of some of the electrode contact levels among the catheter electrodes as weighted electrode contact level mass centers in response to each of the respective contact levels.

[0120] (11) A method for aligning catheters, Inserting a catheter into a cavity in a body part so that the catheter electrode contacts tissue at each location within the body part, Receiving the signal provided by the catheter, In response to the received signal, the contact level between some of the catheter electrodes and the tissue of the body part is evaluated, In response to the respective contact levels of some of the catheter electrodes, to find a direction in which the catheter should be moved in order to improve at least one of the respective contact levels of at least one of the catheter electrodes, A catheter alignment method comprising rendering on a display a representation of the catheter in response to the received signal, and a directional indicator indicating the direction in which the catheter should be moved in response to the found direction. (12) The method according to embodiment 11, wherein the catheter includes an expandable distal end assembly on which the catheter electrode is located. (13) The method according to embodiment 12, wherein the expandable distal end assembly includes an inflatable balloon having an axis around which the catheter electrode is positioned. (14) The method of Embodiment 12, wherein the representation of the catheter includes a two-dimensional (2D) representation of the expandable distal end assembly of the catheter, and shows all representations of the catheter electrodes arranged around the axis of the expandable distal end assembly, with each of the catheter electrodes extending from the central region of the 2D representation toward the outer periphery of the 2D representation. (15) The method according to Embodiment 11, wherein the representation of the catheter includes a three-dimensional (3D) representation of the catheter, and rendering includes rendering the 3D representation of the catheter to a display such that the direction in which the catheter should be moved in the 3D space is indicated by the directional indicators in the 3D space.

[0121] (16) The method according to Embodiment 11, further comprising calculating the center of mass of some of the electrode contact levels of the catheter electrode in response to some of the respective contact levels and position coordinates of the catheter electrode, wherein finding the direction in which the catheter should be moved in response to the calculated center of mass of the electrode contact levels. (17) The method of Embodiment 16, further comprising calculating the center of mass based on the positions of the catheter electrodes in response to the position coordinates of the catheter electrodes, wherein finding the direction in which the catheter should be moved is in response to a line extending from the center of mass of the calculated electrode contact level to the center of mass based on the calculated position. (18) Each of the above contact levels is selected from two contact states, one representing a state of contact with the tissue and the other representing a state of non-contact with the tissue. The method according to Embodiment 16, wherein the calculation includes calculating the center of mass of some of the electrode contact levels of the catheter electrode in response to each of the contact levels having the same one of the two contact states. (19) Each of the above contact levels is selected from at least three states of the quality of contact with the tissue, The method according to Embodiment 16, wherein the calculation includes calculating the mass centers of some of the electrode contact levels of the catheter electrodes as weighted electrode contact level centers in response to each of the contact levels. (20) Each of the above contact levels is selected from the respective sliding scales of the quality of contact with the tissue, The method according to Embodiment 16, wherein the calculation includes calculating the mass centers of some of the electrode contact levels of the catheter electrodes as weighted electrode contact level centers in response to each of the contact levels.

[0122] (21) A catheter protection system, A sheath, including a distal end, configured to be inserted into a part of the living body, A catheter comprising a shaft having a distal portion, wherein an expandable distal end assembly is positioned distal to the distal portion, the catheter is configured to be inserted through the sheath, the distal portion and the expandable distal end assembly protruding from the sheath into the body part, and the catheter includes a pusher positioned within the shaft and coupled to the expandable distal end assembly, wherein adjusting the pusher longitudinally relative to the shaft selectively extends and shortens the distal end assembly; A position tracking subsystem configured to track the relative position between the distal portion of the shaft and the distal end of the sheath, and to find when the distal portion of the shaft enters the distal end of the sheath in response to the tracked relative position, A catheter protection system comprising: a pusher actuator configured to automatically actuate the pusher to extend the expandable distal end assembly in response to the distal portion of the shaft entering the distal end of the sheath. (22) The system according to embodiment 21, further comprising a sound output device configured to provide an audible warning in response to the distal portion of the shaft entering the distal end of the sheath. (23) The position tracking subsystem is configured to detect when the distal portion of the shaft exits the distal end of the sheath in response to the tracked relative position, The system according to embodiment 21, wherein the pusher actuator is configured to automatically actuate the pusher to shorten the expandable distal end assembly in response to the distal portion of the shaft exiting the distal end of the sheath. (24) The system according to embodiment 23, further comprising a sound output device configured to provide an audible warning in response to the distal portion of the shaft exiting the distal end of the sheath. (25) The system according to Embodiment 21, wherein the position tracking subsystem includes a proximal electrode positioned proximal to the expandable distal end assembly on the distal portion of the shaft and a surface electrode configured to be attached to the skin surface of a living organism, the position tracking subsystem is configured to track the relative position between the distal portion of the shaft and the distal end of the sheath in response to a measured electrical impedance between the proximal electrode and the surface electrode.

[0123] (26) The system according to Embodiment 21, wherein the position tracking subsystem comprises a generator coil configured to generate magnetic fields having different frequencies in the body part; a first magnetic coil sensor located near the expandable distal end assembly in the distal portion of the shaft; and a second magnetic coil sensor located at the distal end of the sheath, wherein the first and second magnetic coil sensors are configured to output electrical signals in response to detecting the magnetic field, and the position tracking subsystem is configured to track the relative position between the distal portion of the shaft and the distal end of the sheath in response to the output electrical signals. (27) A catheter protection system, A sheath, including a distal end, configured to be inserted into a part of the living body, A catheter comprising a shaft having a distal portion, wherein an expandable distal end assembly is positioned distal to the distal portion, the catheter is configured to be inserted through the sheath, the distal portion and the expandable distal end assembly protruding from the sheath into the body part, and the catheter includes a pusher positioned within the shaft and coupled to the distal end assembly, wherein adjusting the pusher longitudinally relative to the shaft causes the distal end assembly to selectively extend and shorten. A position tracking subsystem configured to track the relative position between the distal portion of the shaft and the distal end of the sheath, and to find when the distal portion of the shaft enters the distal end of the sheath in response to the tracked relative position, A catheter protection system comprising: a sound output device configured to provide an audible warning in response to the distal portion of the shaft entering the distal end of the sheath. (28) The position tracking subsystem is configured to find out when the distal portion of the shaft exits the distal end of the sheath in response to the tracked relative position, The system according to embodiment 27, wherein the sound output device is configured to provide another audible warning in response to the distal portion of the shaft exiting the distal end of the sheath. (29) The system according to Embodiment 27, wherein the position tracking subsystem comprises a proximal electrode positioned proximal to the expandable distal end assembly on the distal portion of the shaft and a surface electrode configured to be attached to the skin surface of a living organism, and the position tracking subsystem is configured to track the relative position between the distal portion of the shaft and the distal end of the sheath in response to a measured electrical impedance between the proximal electrode and the surface electrode. (30) The system according to Embodiment 27, wherein the position tracking subsystem comprises a generator coil configured to generate magnetic fields having different frequencies in the body part; a first magnetic coil sensor located near the expandable distal end assembly in the distal portion of the shaft; and a second magnetic coil sensor located at the distal end of the sheath, wherein the first and second magnetic coil sensors are configured to output their respective electrical signals in response to detecting the magnetic field, and the position tracking subsystem is configured to track the relative position between the distal portion of the shaft and the distal end of the sheath in response to the output electrical signals.

[0124] (31) A method for protecting a catheter, Inserting a sheath into a part of the living body, Inserting a catheter through the sheath, wherein the distal portion of the catheter shaft and the expandable distal end assembly of the catheter protrude from the sheath into the body part, A pusher, positioned within the shaft and coupled to the expandable distal end assembly, is adjusted longitudinally relative to the shaft to selectively extend and shorten the expandable distal end assembly. Tracking the relative position between the distal portion of the shaft and the distal end of the sheath, In response to the tracked relative position, find when the distal portion of the shaft enters the distal end of the sheath, A catheter protection method comprising: automatically acting the pusher to extend the expandable distal end assembly in response to the distal portion of the shaft entering the distal end of the sheath. (32) The method according to embodiment 31, further comprising providing an audible warning in response to the distal portion of the shaft entering the distal end of the sheath. (33) In response to the tracked relative position, find when the distal portion of the shaft exits the distal end of the sheath, The method according to embodiment 31, further comprising: automatically acting the pusher to shorten the expandable distal end assembly in response to the distal portion of the shaft exiting the distal end of the sheath. (34) The method according to embodiment 33, further comprising providing an audible warning in response to the distal portion of the shaft exiting the distal end of the sheath. (35) The method according to Embodiment 31, wherein the tracking includes tracking the relative position between the distal portion of the shaft and the distal end of the sheath in response to a measured electrical impedance between a proximal electrode positioned proximal to the expandable distal end assembly on the distal portion of the shaft and a body surface electrode attached to the skin surface of the living organism.

[0125] (36) Generating a magnetic field having different frequencies in the body part, The method according to Embodiment 31, further comprising: a first magnetic coil sensor located near the expandable distal end assembly in the distal portion of the shaft and a second magnetic coil sensor located at the distal end of the sheath outputting electrical signals in response to detecting the magnetic field, wherein the tracking includes tracking the relative position between the distal portion of the shaft and the distal end of the sheath in response to the outputted electrical signals. (37) A method for protecting a catheter, Inserting a sheath into a part of the living body, Inserting a catheter through the sheath, wherein the distal portion of the catheter shaft and the expandable distal end assembly of the catheter protrude from the sheath into the body part, A pusher, positioned within the shaft and coupled to the expandable distal end assembly, is adjusted longitudinally relative to the shaft to selectively extend and shorten the expandable distal end assembly. Tracking the relative position between the distal portion of the shaft and the distal end of the sheath, In response to the tracked relative position, find when the distal portion of the shaft enters the distal end of the sheath, A catheter protection method comprising providing an audible warning in response to the distal portion of the shaft entering the distal end of the sheath. (38) In response to the tracked relative position, find when the distal portion of the shaft exits the distal end of the sheath, The method according to embodiment 37, further comprising providing another audible warning in response to the distal portion of the shaft exiting the distal end of the sheath. (39) The method of Embodiment 37, wherein the tracking includes tracking the relative position between the distal portion of the shaft and the distal end of the sheath in response to a measured electrical impedance between a proximal electrode positioned proximal to the expandable distal end assembly on the distal portion of the shaft and a body surface electrode attached to the skin surface of the living body. (40) Generating a magnetic field having different frequencies in the body part, The method according to Embodiment 37, further comprising: a first magnetic coil sensor located near the expandable distal end assembly in the distal portion of the shaft and a second magnetic coil sensor located at the distal end of the sheath outputting electrical signals in response to detecting the magnetic field, wherein the tracking includes tracking the relative position between the distal portion of the shaft and the distal end of the sheath in response to the outputted electrical signals.

Claims

1. A catheter alignment system, A catheter configured to be inserted into a body part of a living organism, comprising catheter electrodes configured to contact tissue at various locations within the body part, The display and A processing circuit, Receiving the signal provided by the catheter, In response to the received signal, the contact level between some of the catheter electrodes and the tissue of the body part is evaluated, Based on the combination of electrodes whose contact level exceeds a given limit and electrodes whose contact level is below a given limit, the direction in which the catheter should be moved is determined by using a pre-entered lookup table. A catheter alignment system comprising: a processing circuit configured to render on the display a representation of the catheter in response to the received signal, and a directional indicator indicating the direction in which the catheter should be moved in response to the found direction.

2. The system according to claim 1, wherein the aforementioned direction is a direction referenced with respect to the longitudinal axis.

3. The system according to claim 2, wherein the representation of the catheter includes a two-dimensional (2D) representation of an expandable distal end assembly of the catheter, and shows all representations of the catheter electrodes arranged around the longitudinal axis, with each of the catheter electrodes extending from the central region of the 2D representation toward the outer periphery of the 2D representation.

4. The system according to any one of claims 1 to 3, wherein the representation of the catheter includes a three-dimensional (3D) representation of the catheter, and the directional indicator indicates the direction in which the catheter should be moved in 3D space.

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