Method and system for calculating and utilizing PFA ablation index

Abstract

To provide a system and method for displaying information related to irreversible electroporation of biotissues.SOLUTION: The invention provides a method, an apparatus and a computer program product. The method comprises: receiving an input from a force sensor on a catheter, the catheter comprising electrodes for ablating a heart of a patient, the catheter placed at a location within the heart; based at least on the received input, calculating a predicted PFA ablation index (PFA AI) of ablation to be caused by applying by the catheter a force equal to an assessment at the location for a predetermined number of electrical pulses having a predetermined magnitude and a predetermined duration, where the calculation is in accordance with a predefined formula; and displaying the predicted PFA AI to a user of the catheter.SELECTED DRAWING: Figure 1A

Description

[Technical field]

[0001] FIELD OF THE DISCLOSURE The present disclosure relates generally to medical devices, and more particularly to systems and methods for displaying information relating to irreversible electroporation of biological tissue. [Background technology]

[0002] Arrhythmias can be caused by problems with the electrical conduction system of the heart, particularly electrical activity at one or more points or regions in the walls of the heart chambers. Atrial fibrillation is an arrhythmia characterized by disorganized signals that cause the atria (left and / or right atria) to contract in a very rapid, asynchronous heart rhythm.

[0003] A common treatment for atrial fibrillation, also known as A-fib, is ablation, which uses energy to create scarring in one or more active areas of the heart's wall in order to block the erroneous electrical signals that contribute to the chaotic signal and restore a typical heartbeat.

[0004] Irreversible electroporation (IRE), also called pulsed field ablation (PFA), is a soft tissue ablation technique that applies short pulses of high amplitude DC signals through a probe in contact with or in close proximity to the tissue to generate an electric field that can result in lethal nanopores in cell membranes, thereby disrupting cellular homeostasis (internal physical and chemical conditions). Cell death after IRE is due to apoptosis (programmed cell death) and not necrosis (cell injury that results in the destruction of the cell through the action of the cell's own enzymes) as in all other heat or radiation based ablation techniques. IRE is commonly used in tumor ablation in areas where precision and preservation of the extracellular matrix, blood flow, and nerves are critical.

[0005] An exemplary pulsed field generator and controller for controlling a PFA pulse or PFA application is shown and described in U.S. Patent Application No. 20210186604(A1), the entirety of which is incorporated by reference herein for all purposes. [Brief description of the drawings]

[0006] A more complete understanding of the present disclosure will be obtained from the following detailed description of the embodiments of the present disclosure when read in conjunction with the drawings. [Figure 1A] 1 is a schematic, depiction of a catheter-based electrophysiological (EP) mapping and ablation system, according to some exemplary embodiments of the present disclosure. [Figure 1B] 1 is a schematic, pictorial illustration of a catheter, according to some exemplary embodiments of the present disclosure; [Diagram 2] 1 is a flowchart of steps in a method for calculating, displaying, and utilizing a predicted PFA index, according to some exemplary embodiments of the present disclosure. [Diagram 3] FIG. 1 is a schematic block diagram of a computing platform for calculating, displaying, and utilizing a predicted PFA index, according to some exemplary embodiments of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0007] In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. However, it will be apparent to those skilled in the art that the present invention may be practiced without these specific details. In other instances, well-known circuits, control logic, and details of computer program instructions for conventional algorithms and processes have not been shown in detail in order to avoid unnecessarily obscuring the present invention.

[0008] Software programming code embodying aspects of the invention is typically maintained in permanent storage, such as a computer readable medium. In a client-server environment, such software programming code may be stored on a client or a server. The software programming code may be embodied in any of a variety of known media for use with data processing systems, including, but not limited to, magnetic and optical storage devices, such as disk drives, magnetic tapes, compact discs (CDs), digital video discs (DVDs), and computer instruction signals embodied in a transmission medium, with or without a carrier wave upon which the signals are modulated. For example, the transmission medium may include a communications network, such as the Internet. Additionally, while the invention may be embodied in computer software, the functionality necessary to carry out the invention may alternatively be embodied, in part or in whole, using hardware components, such as application specific integrated circuits or other hardware, or some combination of hardware components and software.

[0009] Overview Pulsed field ablation (PFA) is a modality that ablates tissue cells by generating an electric field in a region of interest to induce irreversible electroporation (IRE) to induce apoptosis (programmed cell death) of the tissue cells. The IRE field is typically delivered by a signal generator in the form of one or more trains of high-voltage pulses.

[0010] PFA may be delivered using bipolar or monopolar delivery. In bipolar delivery, DC current is delivered between a pair of electrodes near, e.g., typically in contact with, the tissue, generating a local electric field near the tissue to be ablated, thereby killing tissue cells between the electrodes. In monopolar applications, the current is delivered between, e.g., an electrode near, typically in contact with the tissue, and a larger return electrode, which may be a patch on the patient's skin, or a reference electrode on the catheter itself that is immersed in the blood pool or in contact with the tissue at a location away from the location configured for ablation.

[0011] The effectiveness of applying PFA, i.e., ablation quality, can be estimated and / or evaluated based on calculating the PFA ablation index (AI). The PFA ablation index provides an indication of the parameters of the lesion created by PFA, e.g., lesion area and / or depth. The lesion, and therefore the PFA ablation index, may depend on the contact force applied by the catheter to the heart wall, which the inventors have found to be important parameters that affect the quality of the lesion caused, as well as the parameters of the applied pulses, including the number of pulses, their frequency, duration, and amplitude. In particular, unlike the number, frequency, duration, and amplitude of the applied pulses, which are fixed, the applied force is controllable by the physician, thereby allowing the physician to control the quality of the lesion caused by PFA, and therefore the PFA ablation index.

[0012] Optionally, the PFA Ablation Index may be more specifically dependent on the contact force applied by one or more selected electrodes of the catheter. Optionally, the selected electrodes are those determined to be in contact with the heart wall. The PFA Ablation Index may further depend on the particular location within the heart wall where ablation is applied, and may be affected, for example, by the type of tissue, its thickness, and its morphology.

[0013] Typically, ablation is performed by repeated application of pulse trains, with pauses of, for example, about 1 second between applications. The AI ​​may be calculated and displayed after each application by calculating and adding a delta AI to the cumulative AI for all delivered applications so that the user can decide whether and how to apply another pulse train.

[0014] Typically, the pulse parameters are predetermined. Thus, the parameters typically controllable by the physician applying the ablation are the position and force applied by the electrodes to the heart wall. However, the physician may not have a good feel for how much contact force needs to be applied to obtain a satisfactory PFA AI. Thus, by displaying the predicted PFA AI based on the currently applied force, the physician can fine-tune the applied force to achieve the desired effect. Furthermore, the physician may wish to achieve a desired PFA AI and maintain that PFA AI across the lesion created by multiple ablation sites. Thus, in some exemplary embodiments, the calculated and displayed predicted PFA AI may assist the physician in reaching the desired PFA AI and / or achieving a uniform PFA AI across the ablation area created by multiple ablation sites.

[0015] Thus, according to some embodiments of the present disclosure, the contact force may be monitored and a predicted PFA Ablation Index may be calculated based on the assumption that the physician will maintain that contact force through a predetermined number of applications. The predicted PFA AI may be displayed to the physician and may provide the physician with an indication as to how much contact force to apply to achieve a desired PFA AI, e.g., a desired lesion size and / or depth. The displayed predicted PFA may be automatically and continuously updated as the contact force applied by the physician changes.

[0016] In some embodiments, the total force applied by the catheter to the heart wall may be measured, and the force applied by one or more electrodes in contact with the heart wall may contribute to that force, while in other embodiments, the separate forces applied by one or more electrodes may be taken into account.

[0017] The index can be predicted using the same formula used to calculate the actual PFA AI.

[0018] The index may be calculated by integrating the effect of each pulse over a certain number of pulses, and it is assumed that during all pulses the force remains at the same value as currently measured.

[0019] Based on the prediction, the physician can then decide whether to ablate at a particular location and with the current force being applied to the tissue, or whether to change the location and / or the force being applied.

[0020] The predicted PFA ablation index may be displayed to the user continuously or only when the catheter and / or electrodes contact tissue, and the display may vary as the physician changes the position of the catheter and / or electrodes or the force applied by the catheter and / or electrodes against the heart wall.

[0021] System Description Please refer to FIG. 1A, which shows an exemplary catheter-based electrophysiology mapping and ablation system 10. The system 10 may include multiple catheters that are percutaneously inserted by a physician 24 through the vascular system of a patient 23 and into a cavity or vasculature of the heart 12. Typically, a delivery sheath catheter is inserted into the left or right atrium near a desired location of the heart 12. One or more catheters may then be inserted into the delivery sheath catheter to reach a desired location within the heart 12. The multiple catheters, including, for example, catheter 14, may include catheters dedicated to sensing Intracardiac Electrogram (IEGM) signals, catheters dedicated to ablation, and / or catheters for both sensing and ablation. The physician 24 may place a distal tip 28 of the catheter 14 in contact with the heart wall to obtain a prediction of a PFA ablation index in the heart 12 or to ablate a target site.

[0022] Catheter 14 is an exemplary catheter for use with an irreversible electroporation (IRE) ablation system. Catheter 14 may include a distal tip 28. Distal tip 28 may include a number of electrodes 55 connected by wires that extend through catheter 14 to console 30.

[0023] Once the distal end 28 of the catheter 14 has been inserted into the patient's body and reached the target location within the heart 12, the physician 24 may manipulate the catheter 14 to bring an electrode 55 disposed on the distal tip 28 into contact with the target location, such as the ostium of a pulmonary vein.

[0024] In the examples described herein, the electrode 55 can be used for IRE ablation of tissue in the left atrium of the heart 12, such as ostium tissue of the pulmonary veins of the heart 12, with high voltage.

[0025] The proximal end of the catheter 14 receives energy from an IRE ablation energy generator 50 via the control console 30. The IRE power supply 50 may generate pulsed field ablation (PFA) energy, including, but not limited to, monopolar, bipolar, or combinations of high voltage DC pulses, such as may be used to perform irreversible electroporation (IRE). The bipolar pulses may be applied between one or more electrode pairs 55. The electrode pairs 55 to which the pulses are applied may be selected according to applicable protocols to achieve uniformity and penetration depth of the IRE field into the tissue while minimizing thermal heating side effects.

[0026] Referring now also to FIG. 1B, an enlarged pictorial view of the distal tip 28 of catheter 14 is shown.

[0027] Distal tip 28 includes a plurality of electrodes 50 disposed on splines 55. In the exemplary embodiment of FIG. 1B, distal tip 28 includes three splines arranged as a sphere, with each spline having four electrodes disposed thereon.

[0028] The end of each spline is coupled to a central shaft 60. The central shaft 60 may include an irrigation system and one or more irrigation openings 104 for injecting irrigation fluid into the heart.

[0029] The central shaft 60 may further comprise a force sensor 62 configured to sense the total force applied to the heart wall electrodes 55. The force may be calculated as the sum (or average or any other integral) of the forces applied by each of the electrodes 55 on the heart wall, the sum (or average or any other integral) of the forces applied by the electrodes 55 that receive energy according to the protocol and cause ablation, the maximum force applied to the heart wall by any of the electrodes 55, etc.

[0030] The central shaft 60 may further comprise a position sensor 64 for tracking the position and orientation of the distal tip 28. Optionally, and preferably, the position sensor is a magnetic-based position sensor including three magnetic coils for sensing three-dimensional (3D) position and orientation.

[0031] The magnetic-based position sensor may operate in conjunction with a location pad 25 that includes a plurality of magnetic coils 32 configured to generate a magnetic field within a predetermined working volume. The real-time position of either the distal tip 28 of the catheter 14 or the electrodes 55 may be tracked based on the magnetic field generated by the location pad 25 and sensed by the magnetic-based position sensor 64. Details of magnetic-based position sensing technology are described in U.S. Pat. Nos. 5,5391,199, 5,443,489, 5,558,091, 6,172,499, 6,239,724, 6,332,089, 6,484,118, 6,618,612, 6,690,963, 6,788,967, and 6,892,091.

[0032] The system 10 may include one or more electrode patches 38 positioned for skin contact on the patient 23 to establish a position reference for the location pads 25 and impedance-based tracking of the electrodes 55. For impedance-based tracking, a current is directed to the electrodes 55 and sensed at the electrode skin patch 38, so that the location of each electrode can be triangulated via the electrode patch 38. Details of impedance-based position tracking technology are described in U.S. Patent Nos. 7,536,218, 7,756,576, 7,848,787, 7,869,865, and 8,456,182.

[0033] Once ablation energy is applied to tissue, the force applied by distal tip 28 to the heart wall, and optionally the location within the heart, can be used to calculate a PFA Ablation Index. However, the force and optionally the location can also be used to predict the PFA Ablation Index before energy is applied, assuming that physician 24 would apply the same amount of force, so that physician 24 can apply the necessary force at a particular location to achieve a desired lesion and / or a desired PFA AI. The predicted PFA Ablation Index can be calculated based on the force in the same way that the actual PFA Ablation Index is calculated after energy is applied.

[0034] Recorder 11 may record and display electrograms 21 captured by body surface ECG electrodes 18 and intracardiac electrograms (IEGMs) captured by corresponding catheters. Recorder 11 may include pacing capability for pacing the cardiac rhythm and / or may be electrically connected to a stand-alone pacer.

[0035] Patient Interface Unit (PIU) 30 is an interface configured to establish electrical communication between the catheters, electrophysiological equipment, a power source, and a workstation 53 that controls the operation of system 10. The electrophysiological equipment of system 10 may include, for example, multiple catheters, location pads 25, body surface ECG electrodes 18, electrode patches 38, ablation energy generator 50, and recorder 11. Optionally and preferably, PIU 30 additionally includes processing capabilities to implement real-time calculations of catheter positions and perform ECG calculations.

[0036] The workstation 53 includes a processor unit having a memory, a memory or storage device having suitable operating software stored therein, and a user interface function. The workstation 53 may optionally provide multiple functions including: (1) displaying a current PFA index 51 calculated based on the force and position of the catheter 14, and a predicted PFA index 52 on the display device 27, (2) modeling the endocardial anatomical structures in three dimensions (3D) and rendering a model or anatomical map 20 for display on the display device 27, (3) displaying activation sequences (or other data) compiled from the recorded electrograms 21 with representative visual indicators or images superimposed on the rendered anatomical map 20 on the display device 27, (4) displaying real-time positions and orientations of multiple catheters within the heart chambers, and (5) displaying sites of interest, such as locations where ablation energy was applied, on the display device 27. One commercially available product embodying elements of system 10 is available as the CARTO™ 3 system, available from Biosense Webster, Inc., 31A Technology Drive, Irvine, Calif., 92618.

[0037] In some embodiments, the model or anatomical map 20 may show thereon the PFA ablation index or a prediction thereof for multiple locations within the heart.

[0038] In some embodiments, an index may be displayed for areas where the electrodes applied force to the heart wall and may indicate a predicted PFA ablation index based on the force applied at each such location.

[0039] In other embodiments, the index may be displayed for the entire region of the heart wall to allow the physician to select the best location, showing a predicted PFA ablation index calculated based on an average predefined force. In some embodiments, the average force used for the prediction may be a parameter that is learned for each physician, for example the force that the physician normally applies during ablation.

[0040] Referring now to FIG. 2, there is shown a flowchart of steps in a method for calculating, displaying, and utilizing a predicted PFA index, according to some exemplary embodiments of the present disclosure.

[0041] In step 204, a force estimate or measurement can be obtained from a force sensor located at the distal end of the shaft that measures the force with which the physician is pressing the catheter against the body tissue.

[0042] In some embodiments, when assessing force, the local forces exerted by electrodes of an electrode pair that would be activated under the current protocol may be taken into account, such as the sum of the forces exerted by the electrodes, the average, the maximum force exerted by any of the electrodes, etc.

[0043] In other embodiments, the force may be calculated based on the sum, average maximum, or any other measure of the forces applied by all electrodes. Optionally, the force is a force sensed on the distal end of the shaft proximal to where the distal tip assembly is connected to the shaft.

[0044] In step 208, a predicted PFA Ablation Index may be calculated, which predicts the PFA Ablation Index that would be obtained by applying a predetermined number of electrical pulses or pulse trains having a predetermined magnitude and a predetermined duration at that location when the electrode applies a tissue volume force equal to the evaluated force.

[0045] The predicted PFA ablation index can be calculated using the same calculations used to calculate the actual PFA AI after ablation has been applied. The key variable in this calculation is the force applied by the catheter to the heart wall, which the physician may influence. The calculation includes other parameters, including the number of pulses applied, and their respective magnitudes and durations, typically according to a predefined applicable protocol, patient-specific information, if available, or general information based on the general structure of the heart in other cases, as well as the specific locations in the heart and their characteristics, such as the thickness of the tissue at the relevant location, the tissue type, its conductivity, etc.

[0046] The location information may be global to the catheter or specific to each electrode, in which case a predicted PFA ablation index may be combined from the force applied to each active electrode and the characteristics of the particular location where the electrode contacts the body tissue.

[0047] The PFA Ablation Index is described and demonstrated in U.S. Patent Application Publication No. 20210186604(A1), which is incorporated by reference in its entirety for all purposes.

[0048] To predict and control the ablation treatment, the PFA AI may be calculated and displayed to the user. In PFA ablation, a possible scale may correspond to a size S indicating the depth of the lesion, which may depend on F, P, and T, where F is the force applied to the tissue by the catheter, P is the power dissipated during the ablation procedure, and T is the duration of the procedure derived from the number of repetitions of the pulses and pulse trains. In some embodiments, an estimate of the size S may be given by taking the time integral of an equation that includes functions of F, P, and T.

[0049] Estimation may be applied during PFA such that the PFA may be stopped when a desired lesion size and / or PFA AI is reached.

[0050] In an exemplary embodiment of the present disclosure, the PFA AI may be derived by calculating the sum over a period of time of the product of the contact force and the number of iterations.

[0051] The PFA AI can be calculated according to the following formula:

[0052]

number

[0053] AI n is the ablation exponent for the nth pulse application, which is equal to the lesion depth multiplied by a coefficient A, where the depth is a logarithmic function of the force for a particular application (Force(n)): AI n =A * B n * ln(force(n))+Cn, AI n-1 =A * B n-1 * ln(force(n))+C n-1 In the formula, A is a number within a given range, B n is a predetermined parameter determined by the following formula: B n =B0 * ln(n)+B1, In the formula, B0 and B1 are predetermined constants, C n is a predetermined parameter determined by the following formula: C n =C0 * exp(C1 * n) where C0 and C1 are predetermined constants.

[0054] A, B n and C n Values ​​may be empirically determined for each application iteration and calibrated for each type of catheter and type of cardiac structure and given tissue characteristics.

[0055] AI when used in the nth iteration n-1 To ensure that the value of AI is not taken from a previous calculation, n and AI n-1 Note that, is calculated for each iteration. The displayed PFA may be updated with each application.

[0056] The predicted PFA AI can be calculated similarly. However, since the applied force is assumed to be constant across all applications, the formula simplifies to: Predicted PFA AI=AI N -AI1 During the ceremony, AI1=A * B1+ln(force)+C1 AI N =A * B N * ln(force)+C N and Force is a measure of the force applied by the catheter at the predicted time and is assumed to be constant throughout all applications; B N =B0 * ln(N)+B1, C N =C0 * exp(C1 * N).

[0057] In some embodiments, both the PFA AI and the predicted PFA AI may be provided to the user as a dimensionless number or range of dimensionless numbers between minimum and maximum values ​​that represent ideal ablation and ablation that is less than ideal damage, respectively. In one example, the ablation index is a dimensionless scale between two limit values, such as 0 and 1000, 250 and 850, etc.

[0058] AI when used in the nth iteration for the actual PFA n-1 To ensure that the value of AI is not taken from a previous calculation, n and AI n-1 Note that the AI ​​is calculated for each application. The displayed PFA may be updated with each application. However, the predicted AI is calculated for a given number of applications based on the measured instantaneous forces, and the predicted AI is the value displayed.

[0059] Based on the predicted ablation index, the physician can decide to ablate or repeat the ablation at a particular location and / or the physician can decide whether more or less contact force is desired during ablation.

[0060] In step 212, the predicted PFA Ablation Index may be displayed to a user of the system, such as a physician, as shown in text 51 of Figure 1. Optionally, the predicted PFA Ablation Index is displayed alongside a display of the actual PFA Ablation Index.

[0061] Additionally or alternatively, a map of the heart may be updated, and each of a number of locations on the map may be associated with and display a predicted PFA index calculated when the physician places the catheter in contact with the cardiac tissue. The map may be color coded, shade coded, pattern coded, etc.

[0062] Additionally or alternatively, a map of the heart may be displayed showing a general map of predicted PFA ablation indices at multiple locations based on tissue type and its thickness. The map may display indices based on a general predetermined force or typical force applied by the physician as learned from the physician's current or previous sessions.

[0063] The calculations and display may be updated every predetermined period, such as every 1 second, every 5 seconds, etc. In an alternative embodiment, the calculations and display may be updated continuously, for example, every time the catheter is moved.

[0064] In step 216, optionally following user commands or confirmation of a displayed notification, the generator may be operated by the user and IRE energy may be delivered to the electrodes and thus to the tissue according to the applicable protocol. Thus, a predetermined number of pulses of current of a predetermined width are provided to the relevant electrodes and thus to their locations to produce ablation.

[0065] Provided that an ablation has been performed, an actual PFA Ablation Index can be calculated and displayed in step 220. Typically, an actual PFA AI is calculated for each application and a cumulative PFA AI is displayed after each application as ablation is being applied.

[0066] In some embodiments, after application, the actual PFA ablation index can be compared to the predicted value to obtain at least one difference.

[0067] In some embodiments, the comparison results, including at least one difference, may be used to learn predictive parameters so that future predictions become more accurate. For example, if the prediction is consistently higher or lower than the actual value, the prediction may be decreased or increased, respectively. In further cases, more complex relationships may be learned between any two or more of the applied force, tissue properties, catheter configuration, and applied protocol. Learning may be performed automatically by a processor, manually by a human operator, or in a hybrid manner.

[0068] Referring now to FIG. 3, there is shown a block diagram of a computing platform 300 for calculating, displaying and utilizing predicted PFA ablation index, according to certain exemplary embodiments of the present disclosure.

[0069] The computing platform 300 may be embedded within the console 30 or the workstation 53, although it will be understood that it may be a stand-alone computing platform or may be embedded elsewhere and in operative communication with the console 30.

[0070] Computing platform 300 may be implemented as one or more computing platforms that may be operatively connected to one another. For example, one or more remote computing platforms may be implemented, for example, on a cloud computer. The other computing platforms may be part of an associated organizational computer network. In other embodiments, all functionality may be provided by one or more computing platforms that are all part of the organizational network.

[0071] The computing platform 300 may include one or more processors 304, which may or may not be located on the same computing platform, and which may be one or more central processing units (CPUs), microprocessors, electronic circuits, integrated circuits (ICs), etc. The processor 304 may be configured to provide the required functionality, for example, by loading into memory and activating software modules stored in a storage device 312, which will be described in more detail below.

[0072] The computing platform 300 may include input / output (I / O) devices 306, such as a display, pointing device, keyboard, touch screen, speaker, microphone, etc. The I / O devices 306 may be utilized to receive input from and provide output to a user, such as a physician, for example, displaying a predicted PFA ablation index, receiving operating instructions, or the like.

[0073] The computing platform 300 may include a communication device 308 for communicating with other devices or computing platforms, e.g., obtaining pressure information from a force sensor, obtaining motion information from a catheter procedure controller, storing data on a remote storage device, etc. The communication module 308 may be adapted to interface with any communication channel, such as a local area network (LAN), a wide area network (WAN), a cellular network, etc., and to use any associated communication protocol.

[0074] The computing platform 300 may include a storage device 312, such as a hard disk drive, a flash disk, a random access memory (RAM), a memory chip, etc. In some exemplary embodiments, the storage device 312 may hold program code operable to cause the processor 304 to perform operations associated with any of the modules listed below or steps of the method of FIG. 2 above. The program code may include one or more executable units, such as functions, libraries, stand-alone programs, etc., adapted to execute instructions as detailed below.

[0075] Alternatively or additionally, the instructions provided may be stored on a non-transitory, tangible computer readable medium, such as a magnetic, optical, or electronic memory.

[0076] The storage device 312 may include a communications module 316 for transmitting data to and receiving data from other systems, such as a catheter control system, a force sensor, an external storage device, a display system, etc., via the communications device 308. In particular, the communications module 316 may be operable in receiving force measurements from one or more force sensors associated with the catheter, e.g., located at the distal end of the catheter.

[0077] The storage device 312 may include a PFA ablation index prediction module 320 for calculating a predicted index based on the sensed force, electrode and signal parameters, and optionally location, as detailed in connection with step 208 above.

[0078] The storage device 312 may include a PFA ablation index comparison module 324 for comparing the predicted PFA ablation index with the actual PFA ablation index measured at the post-ablation location.

[0079] The storage device 312 can include a PFA prediction parameter learning module 328 for adapting the parameters or calculations of the PFA ablation index prediction module 320 based on the difference between the predicted PFA ablation index and the actual one. Thus, the PFA ablation index prediction module 328 can adapt its internal parameters or calculations so that future predictions more closely predict the actual results to enable the physician to make better decisions about where to perform the ablation and how much force to apply during the ablation. Learning the parameters can be performed automatically, manually, or a combination thereof.

[0080] The storage device 312 may also include a data and control flow management module 332 for initiating the above modules with the necessary inputs in the correct order, for example, for initiating the PFA prediction parameter learning module 328 after predicted and actual PFA ablation index information is available for multiple locations.

[0081] The storage device 312 may include a user interface 336 for rendering a display to a user to be displayed on the display device 27, such as a predicted PFA ablation index 51, a cardiac index ablation index or a map of a prediction thereof. The user interface 336 may also be operable in receiving command parameters and operating parameters, such as from a controller 32 operated by a user.

[0082] It will be understood that the steps and modules disclosed above may include, in addition to software, hardware, firmware, or other modules, required to operate the catheter, display the catheter procedure process, perform other calculations such as complex fractionated electrogram (CFE) analysis, generate cardiac maps, etc. Further details on methods and systems may be found, for example, in U.S. Patent Nos. 8,676,305 and 9,629,567, which are incorporated by reference herein in their entireties for any purpose.

[0083] The present invention may be a system, a method, and / or a computer program product. The computer program product may include a computer-readable storage medium having computer-readable program instructions for causing a processor to perform aspects of the present invention.

[0084] A computer-readable storage medium may be a tangible device capable of holding and storing instructions for use by an instruction execution device. A computer-readable storage medium may be, for example, but not limited to, an electronic storage device, a magnetic storage device, an optical storage device, an electromagnetic storage device, a semiconductor storage device, or any suitable combination of the foregoing. A non-exhaustive list of more specific examples of computer-readable storage media includes portable computer diskettes, hard disks, random access memories (RAMs), read-only memories (ROMs), erasable programmable read-only memories (EPROMs or flash memories), static random access memories (SRAMs), portable compact disk read-only memories (CD-ROMs), digital versatile disks (DVDs), memory sticks, floppy disks, mechanically encoded devices such as punch cards or ridges in grooves with instructions recorded on them, and any suitable combination of the above. As used herein, a computer-readable storage medium should not be construed as being a signal that is itself ephemeral, such as an electric wave or other freely propagating electromagnetic wave, an electromagnetic wave propagating through a wave guide or other transmission medium (e.g., light pulses passing through a fiber optic cable), or an electric signal transmitted through a flow line.

[0085] The computer-readable program instructions described herein can be downloaded from a computer-readable storage medium to each computing / processing device or to an external computer or external storage device via a network, such as the Internet, a local area network, a wide area network, and / or a wireless network. The network can include copper transmission cables, optical transmission fiber, wireless transmission, routers, firewalls, switches, gateway computers, and / or edge servers. A network adapter card or network interface of each computing / processing device receives the computer-readable program instructions from the network and transfers the computer-readable program instructions to a computer-readable storage medium within the respective computing / processing device for storage.

[0086] The computer readable program instructions for carrying out the operations of the present invention may be either assembler instructions, instruction set architecture instructions, machine instructions, machine dependent instructions, microcode, firmware instructions, state setting data, or source or object code written in any combination of one or more programming languages, such as Java, C, C++, Python, etc. The computer readable program instructions may be executed entirely on the user's computer, partially on the user's computer, as a standalone software package, partially on the user's computer, partially on a remote computer, or entirely on a remote computer or server. In the latter scenario, the remote computer may be connected to the user's computer via any type of network, including a local area network (LAN) or a wide area network (WAN), or may be connected to an external computer (e.g., via the Internet using an Internet Service Provider). In some embodiments, electronic circuitry, including, for example, programmable logic circuits, field programmable gate arrays (FPGAs), or programmable logic arrays (PLAs), may execute the computer readable program instructions by utilizing state information of the computer readable program instructions to individualize the electronic circuitry to carry out aspects of the present invention.

[0087] Aspects of the present invention are described herein with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems) and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer readable program instructions.

[0088] These computer readable program instructions may be provided to a processor of a general purpose computer, special purpose computer, or other programmable data processing device to generate a machine such that the instructions are executed by the processor of the computer or other programmable data processing device to create means for performing the functions / acts specified in one or more blocks of the flowcharts and / or block diagrams. These computer readable program instructions may also be stored on a computer readable storage medium that can cause a computer, programmable data processing apparatus, and / or other device to function in a particular manner, such that the computer readable storage medium on which the instructions are stored includes an article of manufacture that includes instructions that implement aspects of the functions / acts specified in one or more blocks of the flowcharts and / or block diagrams.

[0089] The computer-readable program instructions may be loaded onto a computer, other programmable data processing apparatus, or other device to cause a sequence of operational steps to be performed on the computer, other programmable apparatus, or other device to generate a computer-implemented process such that the instructions executing on the computer, other programmable apparatus, or other device perform the functions / acts defined in the flowchart and / or block diagram blocks.

[0090] The flow charts and block diagrams in the figures illustrate the structure, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of the present invention. In this regard, each block in the flow charts or block diagrams may represent a module, segment, or portion of instructions that includes one or more executable instructions for implementing the illustrated logical function. In some alternative implementations, the functions shown in the blocks may occur in an order other than that shown in the figures. For example, two blocks shown in succession may in fact be executed substantially simultaneously, or the blocks may sometimes be executed in the reverse order, depending on the functionality involved. It should also be noted that each block of the block diagrams and / or flow diagrams, and combinations of blocks in the block diagrams and / or flow diagrams, may be implemented by a dedicated hardware-based system that performs a particular function or operation, or may operate or execute a combination of dedicated hardware and computer instructions. EXAMPLES

[0091] Example 1 The method includes receiving input from a force sensor on a catheter, the catheter comprising electrodes for ablating a patient's heart, the catheter being positioned at a location within the heart; calculating, based at least on the received input, a predicted PFA Ablation Index (PFA AI) of an ablation caused by the catheter applying a force equal to an estimate at the location for a predetermined number of electrical pulses having a predetermined magnitude and a predetermined duration, the calculation according to a predetermined formula; and displaying the predicted PFA AI to a user of the catheter.

[0092] Example 2 2. The method of example 1, further comprising receiving an updated input from a force sensor and repeating the calculating and displaying for the updated input.

[0093] Example 3 The method of example 1, further comprising displaying the calculated actual PFA AI after ablation is performed at the actual force measured during application along with a predicted PFA Ablation Index.

[0094] Example 4 The method of Example 1, wherein the calculation is equivalent to calculating the PFA AI after the ablation is applied with a force equal to the evaluation.

[0095] Example 5 The predicted PFA AI calculation is based on the location on the wall of the heart, as described in Example 1.

[0096] Example 6 The method described in Example 1, wherein the predicted PFA AI calculation is based on the tissue type, tissue thickness, or tissue conductivity of the tissue at the location on the wall of the heart.

[0097] Example 7 The predicted PFA AI calculation is based on the characteristics of the electrode or the applied signal, as described in Example 1.

[0098] Example 8 Calculating the predicted PFA AI is based on the following formula: Predicted PFA AI=AI N -AI1 During the ceremony, AI1=A * B1+ln(force)+C1 AI N =A * B N * ln(force)+C N and N is equal to the number of PFA pulses applied. Force is a measure of the force applied by the catheter at the predicted time and is assumed to be constant throughout all applications; B N =B0 * ln(N)+B1, CN =C0 * exp(C1 * N) A is a number within a given range, The method of claim 1, wherein B0, B1, C0, and C1 are predetermined constants.

[0099] Example 9 A, B0, B1, C0 and C1 are empirically determined for each catheter type and given tissue characteristics in the type and location of the cardiac structure, as described in Example 8.

[0100] Example 10 1. A computerized device having a processor coupled to a memory unit, the processor being adapted to perform the steps of: receiving input from a force sensor on a catheter, the catheter comprising electrodes for ablating a patient's heart, the catheter being positioned at a location within the heart; calculating, based at least on the received input, a predicted PFA Ablation Index (PFA AI) of an ablation caused by the catheter applying a force equal to an estimate at the location for a predetermined number of electrical pulses having a predetermined magnitude and a predetermined duration, the calculation according to a predetermined formula; and displaying the predicted PFA AI to a user of the catheter.

[0101] Example 11 The apparatus of example 10, wherein the processor is further adapted to receive an updated input from the force sensor and repeat the calculating and displaying for the updated input.

[0102] Example 12 The device of Example 10, wherein the processor is further adapted to display the calculated actual PFA AI after ablation is performed at the actual force measured during application together with the predicted PFA ablation index.

[0103] (Example 13) The device of Example 10, wherein the calculation is equivalent to the calculation of the PFA AI after ablation is applied with a force equal to the evaluation.

[0104] Example 14 The device of Example 10, wherein the predicted PFA AI calculation is based on the location on the wall of the heart.

[0105] Example 15 The apparatus of Example 10, wherein the predicted PFA AI calculation is based on the tissue type, tissue thickness, or tissue conductivity of the tissue at the location on the wall of the heart.

[0106] Example 16 The device of Example 10, wherein the predicted PFA AI calculation is based on the characteristics of the electrodes or the applied signal.

[0107] (Example 17) Calculating the predicted PFA AI is based on the following formula: Predicted PFA AI=AI N -AI1 During the ceremony, AI1=A * B1+ln(force)+C1 AI N =A * B N * ln(force)+C N and N is equal to the number of PFA pulses applied. Force is a measure of the force applied by the catheter at the predicted time and is assumed to be constant throughout all applications; B N =B0 * ln(N)+B1, C N =C0 * exp(C1 * N) A is a number within a given range, The apparatus of example 10, wherein B0, B1, C0, and C1 are predetermined constants.

[0108] (Example 18) A, B0, B1, C0 and C1 are empirically determined for each catheter type and given tissue characteristics in the type and location of the cardiac structure, the device described in Example 10.

[0109] (Example 19) 1. A computer program product comprising a non-transitory computer-readable medium carrying program instructions which, when read by a processor, cause the processor to: receive input from a force sensor on a catheter, the catheter comprising electrodes for ablating a patient's heart, the catheter being positioned at a location within the heart; calculate, based at least on the received input, a predicted PFA Ablation Index (PFA AI) of an ablation caused by the catheter applying a force equal to the estimate at the location for a predetermined number of electrical pulses having a predetermined magnitude and a predetermined duration, the calculation according to a predetermined formula; and displaying the predicted PFA AI to a user of the catheter.

[0110] (Example 20) The computer program product of Example 19, wherein calculating the predicted PFA AI is based on the following formula:

[0111] Although the examples described herein primarily address cardiac diagnostic applications, the methods and systems described herein may also be used in other medical applications.

[0112] It will be understood that the embodiments described above are given by way of example, and that the present disclosure is not limited to what is particularly shown and described hereinabove. Rather, the scope of the present disclosure includes both combinations and subcombinations of the various features described hereinabove, as well as variations and modifications thereof not disclosed in the prior art that would occur to one skilled in the art upon receipt of the foregoing description.

[0113] [Embodiment] (1) A method comprising: receiving input from a force sensor on a catheter, the catheter comprising electrodes for ablating a patient's heart, the catheter being positioned at a location within the heart; calculating, based at least on the received input, a predicted PFA Ablation Index (PFA AI) of the ablation caused by applying a force equal to the estimate at the location by the catheter for a predetermined number of electrical pulses having a predetermined magnitude and a predetermined duration, the calculation according to a predetermined formula; displaying the predicted PFA AI to a user of the catheter; and A method comprising: (2) receiving updated input from the force sensor; and 2. The method of claim 1, further comprising repeating the calculating and displaying for the updated input. (3) The method of embodiment 1, further comprising displaying an actual PFA AI calculated after ablation is performed with the actual force measured during application together with the predicted PFA Ablation Index. (4) The method of embodiment 1, wherein the calculation is equivalent to a calculation of the PFA AI after ablation is applied with a force equal to the assessment. (5) The method of embodiment 1, wherein the predicted PFA AI calculation is based on the location on the wall of the heart.

[0114] (6) The method of embodiment 1, wherein the predicted PFA AI calculation is based on tissue type, tissue thickness, or tissue conductivity of tissue at the location on the wall of the heart. (7) The method of embodiment 1, wherein the predicted PFA AI calculation is based on characteristics of the electrode or the applied signal. (8) calculating the predicted PFA AI based on the following formula: Predicted PFA AI=AI N -AI1 During the ceremony, AI1=A * B1+ln(force)+C1, AI N =A * B N * ln(force)+C N and N is equal to the number of PFA pulses applied. Force is the measurement of the force applied by the catheter at the predicted time, assumed to be constant throughout all applications; B N =B0 * ln(N)+B1, C N =C0 * exp(C1 * N) A is a number within a given range, The method of embodiment 1, wherein B0, B1, C0, and C1 are predetermined constants. (9) The method of embodiment 8, wherein A, B0, B1, C0 and C1 are empirically determined for each catheter type and type of cardiac structure and given tissue characteristics at said location. (10) A computerized apparatus having a processor coupled to a memory unit, the processor comprising: receiving input from a force sensor on a catheter, the catheter comprising electrodes for ablating a patient's heart, the catheter being positioned at a location within the heart; calculating, based at least on the received input, a predicted PFA Ablation Index (PFA AI) of the ablation caused by applying a force equal to the estimate at the location by the catheter for a predetermined number of electrical pulses having a predetermined magnitude and a predetermined duration, the calculation according to a predetermined formula; displaying the predicted PFA AI to a user of the catheter; A computerized apparatus adapted to carry out the steps of:

[0115] (11) The processor: receiving updated input from the force sensor; 11. The apparatus of claim 10, further adapted to: repeat said calculating and said displaying for said updated input. (12) The device of embodiment 10, wherein the processor is further adapted to display an actual PFA AI calculated after ablation is performed at the actual force measured during application together with the predicted PFA ablation index. (13) The device of embodiment 10, wherein the calculation is equivalent to a calculation of the PFA AI after ablation is applied with a force equal to the evaluation. (14) The device of embodiment 10, wherein the predicted PFA AI calculation is based on the location on the wall of the heart. (15) The device of embodiment 10, wherein the predicted PFA AI calculation is based on tissue type, tissue thickness, or tissue conductivity of tissue at the location on the wall of the heart.

[0116] (16) The device of embodiment 10, wherein the predicted PFA AI calculation is based on characteristics of the electrodes or applied signals. (17) Calculating the predicted PFA AI is based on the following formula: Predicted PFA AI=AI N -AI1 During the ceremony, AI1=A * B1+ln(force)+C1 AI N =A * B N * ln(force)+C N and N is equal to the number of PFA pulses applied. Force is the measurement of the force applied by the catheter at the predicted time, assumed to be constant throughout all applications; B N =B0 * ln(N)+B1, C N =C0 * exp(C1 * N) A is a number within a given range, An apparatus as described in embodiment 10, wherein B0, B1, C0, and C1 are predetermined constants. (18) The device of embodiment 17, wherein A, B0, B1, C0 and C1 are empirically determined for each catheter type and type of cardiac structure and given tissue characteristics at the location. (19) A computer program product comprising a non-transitory computer-readable medium bearing program instructions, the instructions, when read by a processor, causing the processor to: receiving input from a force sensor on a catheter, the catheter comprising electrodes for ablating a patient's heart, the catheter being positioned at a location within the heart; calculating, based at least on the received input, a predicted PFA Ablation Index (PFA AI) of the ablation caused by applying a force equal to the estimate at the location by the catheter for a predetermined number of electrical pulses having a predetermined magnitude and a predetermined duration, the calculation according to a predetermined formula; displaying the predicted PFA AI to a user of the catheter; and A computer program product that causes the (20) The computer program product of embodiment 19, wherein calculating the predicted PFA AI is based on the following formula:

Claims

1. 1. A computerized apparatus having a processor coupled to a memory unit, the processor comprising: receiving input from a force sensor on a catheter, the catheter comprising electrodes for ablating a patient's heart, the catheter being positioned at a location within the heart; calculating, based at least on the received input, a predicted PFA Ablation Index (PFA AI) of the ablation caused by applying a force equal to the estimate at the location by the catheter for a predetermined number of electrical pulses having a predetermined magnitude and a predetermined duration, the calculation according to a predetermined formula; displaying the predicted PFA AI to a user of the catheter; A computerized apparatus adapted to carry out the steps of:

2. The processor, receiving updated input from the force sensor; The apparatus of claim 1 , further adapted to: repeat said calculating and said displaying for said updated input.

3. 2. The apparatus of claim 1, wherein the processor is further adapted to display an actual PFA AI calculated after ablation is performed with the actual force measured during application together with the predicted PFA ablation index.

4. The apparatus of claim 1 , wherein the calculation is equivalent to calculating a PFA AI after an ablation is applied with a force equal to the assessment.

5. The apparatus of claim 1 , wherein the predicted PFA AI calculation is based on the location on the wall of the heart.

6. The apparatus of claim 1 , wherein the predicted PFA AI calculation is based on tissue type, tissue thickness, or tissue conductivity of tissue at the location on the wall of the heart.

7. The apparatus of claim 1 , wherein the predicted PFA AI calculation is based on characteristics of the electrodes or applied signals.

8. Calculating the predicted PFA AI is based on the following formula: Predicted PFA AI = AI Ｎ -AI １ During the ceremony, AI １ = A ＊ B １ + ln(force) + C １ AI Ｎ = A ＊ B Ｎ ＊ ln(force) + C Ｎ and N is equal to the number of times the PFA pulse is applied, Force is the measurement of the force applied by the catheter at the predicted time, assumed to be constant throughout all applications; B Ｎ =B ０ ＊ ln(N)+B １ 、 C Ｎ = C ０ ＊ exp(C １ ＊ N) A is a number within a predetermined range, B ０ , B １ , C ０ , C １ The apparatus of claim 1 , wherein: is a predetermined constant.

9. A, B ０ , B １ , C ０ and C １ The apparatus of claim 8 , wherein x is empirically determined for each catheter type and type of cardiac structure and given tissue characteristics at the location.

10. 1. A computer program product comprising a non-transitory computer readable medium bearing program instructions, the instructions, when read by a processor, causing the processor to: receiving input from a force sensor on a catheter, the catheter comprising electrodes for ablating a patient's heart, the catheter being positioned at a location within the heart; calculating, based at least on the received input, a predicted PFA Ablation Index (PFA AI) of the ablation caused by applying a force equal to the estimate at the location by the catheter for a predetermined number of electrical pulses having a predetermined magnitude and a predetermined duration, the calculation according to a predetermined formula; displaying the predicted PFA AI to a user of the catheter; A computer program product that causes the

11. 11. The computer program product of claim 10, wherein calculating the predicted PFA AI is based on the following formula:

12. 1. A method comprising: receiving input from a force sensor on a catheter, the catheter comprising electrodes for ablating a patient's heart, the catheter being positioned at a location within the heart; calculating, based at least on the received input, a predicted PFA Ablation Index (PFA AI) of the ablation caused by applying a force equal to the estimate at the location by the catheter for a predetermined number of electrical pulses having a predetermined magnitude and a predetermined duration, the calculation according to a predetermined formula; displaying the predicted PFA AI to a user of the catheter; A method comprising:

13. receiving updated input from the force sensor; The method of claim 12 , further comprising: repeating the calculating and displaying for the updated input.

14. 13. The method of claim 12, further comprising displaying an actual PFA AI calculated after ablation has occurred with the actual force measured during application together with the predicted PFA Ablation Index.

15. The method of claim 12 , wherein the calculation is equivalent to calculating a PFA AI after an ablation is applied with a force equal to the assessment.

16. The method of claim 12 , wherein the predicted PFA AI calculation is based on the location on the wall of the heart.

17. The method of claim 12 , wherein the predicted PFA AI calculation is based on tissue type, tissue thickness, or tissue conductivity of tissue at the location on the wall of the heart.

18. The method of claim 12 , wherein the predicted PFA AI calculation is based on characteristics of the electrodes or applied signals.

19. Calculating the predicted PFA AI is based on the following formula: Predicted PFA AI = AI Ｎ -AI １ During the ceremony, AI １ = A ＊ B １ + ln(force) + C １ , AI Ｎ = A ＊ B Ｎ ＊ ln(force) + C Ｎ and N is equal to the number of times the PFA pulse is applied, Force is the measurement of the force applied by the catheter at the predicted time, assumed to be constant throughout all applications; B Ｎ =B ０ ＊ ln(N)+B １ 、 C Ｎ = C ０ ＊ exp(C １ ＊ N) A is a number within a predetermined range, B ０ , B １ , C ０ , C １ The method of claim 12 , wherein: is a predetermined constant.

20. A, B ０ , B １ , C ０ and C １ 20. The method of claim 19, wherein x is empirically determined for each catheter type and type of cardiac structure and given tissue characteristics at the location.

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