Electroanatomical mapping without obtaining a reference signal

Abstract

A system and method for generating an electroanatomical map of the heart are disclosed. The disclosed techniques include measuring a group of activation signals. Each group of activation signals is measured by respective electrodes of a mapping catheter disposed at respective locations within the heart. Here, at least one electrode of the mapping catheter that measures one group of activation signals spatially overlaps with each of the respective electrodes of the mapping catheter that measures another group of activation signals. The disclosed techniques further include obtaining respective sets of time measurements using the overlapping electrodes based on the groups of activation signals. And constructing an electroanatomical map based on the obtained sets of time measurements.

Description

Background Art

[0001] Three-dimensional (3D) electroanatomical maps of the heart are used to visualize the cardiac tissue conduction and propagation of electrical signals across the endocardium. Activation signals (electrograms) can be acquired by mapping catheters that measure those signals at various locations on the endocardium. To detect the activation time at a particular location of the cardiac tissue, the activation signal (measured at that location) is compared to a reference activation signal. Typically, the reference activation signal captures the electrical activity generated by a source, e.g., the sinoatrial node, by a dedicated reference catheter placed near that source, e.g., in the coronary sinus (CS). However, in some patients, physicians are unable to insert a reference catheter into the CS. Further, in some patients, it has been found to be difficult to insert multiple catheters (e.g., a reference catheter, a mapping catheter, and optionally an ablation catheter) into the anatomical structure of the femoral vein.

[0002] Furthermore, in some situations, the reference catheter cannot be fixed in one location, and as a result, a moving spatio-temporal reference frame can be disrupted. In other situations, the myocardium being measured by the reference catheter may have electrical dissociation from the area being mapped, rendering the use of the reference catheter ineffective for generating a 3D electroanatomical map.

Summary of the Invention

Means for Solving the Problems

[0003] Accordingly, there is a need for a technique for generating a 3D electroanatomical map without the need to insert a reference catheter for obtaining a reference activation signal. Such a technique enables cardiac mapping using a single mapping catheter having a single access point to the heart.

Brief Description of the Drawings

[0004] A more detailed understanding can be obtained from the following description, which is presented as an example in conjunction with the accompanying drawings, where like reference numerals in the figures indicate like elements.

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[0005] As disclosed herein, a multi-electrode mapping catheter can be used to generate 3D electroanatomical maps such as a local arrival time (LAT) map of a cardiac chamber. This can be achieved without using an additional catheter for acquisition of a reference activation signal. To that end, a group of activation signals may be acquired, and the group of activation signals may be measured by the electrodes of the mapping catheter when disposed at respective locations on the endocardium. Next, a set of time measurements can be derived from each respective group of activation signals. One set of time measurements is associated with another set of time measurements through measurements in two sets corresponding to activation signals measured by spatially overlapping electrodes. The aspects of 3D electroanatomical mapping described herein can be implemented by a cardiac mapping system such as the CARTO® 3 3D system. Generally, a cardiac mapping system can provide, for example, a 3D visualization of the anatomical structure of the heart with an LAT map overlaid that visualizes the electrical properties of the heart. A mapping system that can be utilized to employ aspects of 3D electroanatomical mapping is described with reference to FIGS. 1-5.

[0006] Aspects of the present disclosure describe a method for generating an electroanatomical map of the heart. The method includes measuring a group of activation signals. Each group of activation signals is measured by respective electrodes of a mapping catheter disposed at respective locations within the heart, and at least one electrode of the mapping catheter that measures an activation signal of one of the groups spatially overlaps with each of the electrodes of the mapping catheter that measures an activation signal of another of the groups. The method further includes obtaining respective sets of time measurements using the overlapping electrodes based on the group of activation signals. Next, an electroanatomical map is constructed based on the obtained sets of time measurements.

[0007] Aspects of the present disclosure also describe a system for generating an electroanatomical map of a heart. The system includes at least one processor and a memory storing instructions. When executed by the at least one processor, the instructions cause the system to measure a group of activation signals. Each group of activation signals is measured by respective electrodes of a mapping catheter disposed at respective locations within the heart, and at least one electrode of the mapping catheter that measures an activation signal of one of the groups spatially overlaps with each of the respective electrodes of the mapping catheter that measures an activation signal of another of the groups. The instructions further cause the system to obtain respective sets of time measurements using the overlapping electrodes based on the groups of activation signals, and then construct an electroanatomical map based on the obtained sets of time measurements.

[0008] Furthermore, aspects of the present disclosure describe a non-transitory computer-readable medium including instructions executable by at least one processor for implementing a method for generating an electroanatomical map of a heart. The method includes measuring a group of activation signals. Each group of activation signals is measured by respective electrodes of a mapping catheter disposed at respective locations within the heart, and at least one electrode of the mapping catheter that measures an activation signal of one of the groups spatially overlaps with each of the respective electrodes of the mapping catheter that measures an activation signal of another of the groups. The method further includes obtaining respective sets of time measurements using the overlapping electrodes based on the groups of activation signals. Next, an electroanatomical map is constructed based on the obtained sets of time measurements.

[0009] FIG. 1 is a diagram of an exemplary cardiac mapping system 100, based on which one or more features of the present disclosure may be implemented. System 100 may include a console 124, a display 127, and a catheter 140 that are operated by a user (e.g., a physician or medical professional) 130. System 100 can obtain anatomical and electrical measurements taken from an organ of a patient 128 such as the heart 126, visualize the obtained anatomical and electrical measurements, and perform a cardiac ablation procedure. Insertion illustration 145 shows an enlarged view of catheter 140, and insertion illustration 125 shows catheter 140 within the cardiac chamber of heart 120. An example of system 100 is the Biosense Webster's CARTO® 3 3D mapping system.

[0010] The catheter 140 shown in FIG. 1 represents one or more catheters that may be employed by system 100, including an ablation catheter and a mapping catheter. The ablation catheter may be configured to damage (ablate) a tissue region of an internal organ. The mapping catheter, which includes one or more electrodes, may be configured to obtain biometric data including electrical signals. System 100 may include one or more probes 121 having a shaft 122 that can be navigated by a physician 130 into a body part such as the heart 126 of a patient 128 lying on a table 129. The physician 130 can insert the shaft 122 into the sheath 123 while operating the distal end of the shaft 122 using a manipulator near the proximal end of the catheter 140 and / or deflecting it from the sheath 123. As shown in FIG. 145, the catheter 140 may be attached to the distal end of the shaft 122. The catheter 140 can be inserted into the sheath 123 in a folded state and subsequently expanded within the heart 126.

[0011] In an aspect, the electrical properties of the heart (e.g., biometric measurement data derived from electrical signals acquired by the electrodes of a catheter) may represent information associated with, for example, LAT, electrical activity, topology, unipolar or bipolar voltage, dominant frequency, or impedance. LAT can represent the time at which electrical activity was measured at a particular location. LAT can be calculated based on a normalized initial starting point that can be derived from a reference catheter. Electrical activity can be any applicable electrical signal that can be measured based on one or more thresholds. Electrical activity can be enhanced (e.g., by using a filter to improve the signal-to-noise ratio). Topology can represent the physical structure of a body part or a portion of a body part, or may correspond to changes in the physical structure between different portions of a body part or between different body parts. Dominant frequency can represent a frequency, or a range of frequencies, that is dominant in a portion of a body part and may be different in different portions of the same body part. For example, the dominant frequency of the pulmonary veins of the heart may be different from the dominant frequency of the right atrium of the same heart. Impedance can represent the resistance in a predetermined region of a body part.

[0012] Console 124 of system 100 can include a processing unit 141, a memory 142, and a communication interface circuit 138. The processing unit 141 can be a computer with a multi-core processor and can include a front-end and control components. The memory 142 can include volatile and / or non-volatile memory. The communication interface circuit 138 can be used to transmit and receive signals to and from the catheter 140. Console 124 may be configured to receive biometric data, subsequently process, visualize, and store the biometric data for later processing, or may be configured to transmit data to another system via a network. In one aspect, the processing unit 141 may be external to the console 124, for example, located within the catheter 140, an external device, a mobile device, a cloud-based device, or may be a stand-alone processor. The processing unit 141 can execute software modules programmed to perform the functions of the aspects described herein. The software modules can be downloaded to the processing unit 141 via a network or from a non-transitory tangible medium such as external or local magnetic memory, optical memory, or electronic memory of the console 124.

[0013] System 100 can be modified to implement the aspects disclosed herein. The aspects disclosed herein can be similarly applied using other system components and settings. Additionally, system 100 may include additional components such as elements for sensing electrical activity, wired or wireless connectors, a processing unit, or a display device. Console 124 can include a real-time noise reduction circuit typically configured as a field programmable gate array (FPGA), followed by an analog-to-digital (A / D) electrocardiogram (ECG) or electromyogram (EMG) signal conversion integrated circuit. The output of the A / D ECG or EMG circuit may be processed to implement the methods disclosed herein.

[0014] The console 124 may be connected to the body surface electrode 143 by a cable 139, and the body surface electrode 143 may include an adhesive skin patch attached to the patient 128. The processing unit 141, together with the tracking module, can determine the position coordinates of the catheter 140 within a body part of the patient 128 (e.g., the heart 126). The position coordinates may be based on the impedance or electromagnetic field measured between the body surface electrode 143 and the electrode (or other electromagnetic components) of the catheter 140. Additionally or alternatively, the position coordinates may be based on the impedance or electromagnetic field measured between a position pad attached to the surface of the bed 129 and the electrode (or other electromagnetic components) of the catheter 140.

[0015] During the procedure, the processing unit 141 can facilitate a rendering 135 of the body part 126 on the display 127 for viewing by the physician 130, and can store data representing the body part in the memory 142. In one aspect, the physician 130 can use one or more input devices such as a touch screen, touch pad, mouse, keyboard, or gesture recognition device to rotate and move the rendered body part 135 (e.g., change the viewing perspective of the rendered body part). For example, the position of the catheter 140 can be changed to collect measurements based on which rendering 135 of the body part 126 is updated. Additionally, the representation of the catheter can be rendered in relation to the rendering of the body part to enable the physician 130 to better navigate the catheter within the body part. In one aspect, the display 127 may be located at a remote location such as a separate hospital or within a separate healthcare provider network.

[0016] FIG. 2 is a block diagram of an exemplary system 200 that can be deployed by the exemplary heart mapping system 100 of FIG. 1, based on which one or more features of the present disclosure may be implemented. The system 200 may include a monitoring and processing system 205, a local system 280, and a remote system 290. The monitoring and processing system 205 may include a sensor 210, a processor 220, a memory 230, an input device 240, an output device 250, and a transceiver 260, e.g., a transmitter and receiver that communicates with a network 270. The system 205 can continuously or periodically monitor, store, process, and transmit biometric data of various patients via the network 270. Examples of the biometric data of the patients may include electrical signals (e.g., ECG signals), anatomical images, blood pressure data, blood glucose data, and temperature data. The biometric data of the patients can be monitored (processed, visualized, transmitted) to facilitate the treatment of various diseases such as cardiovascular diseases (e.g., arrhythmia, cardiomyopathy, and coronary artery disease) and autoimmune diseases (e.g., type I and type II diabetes).

[0017] In one aspect, the monitoring and processing system 205 may represent the console 124 of the system 100 shown in FIG. 1. In another aspect, the monitoring and processing system 205 may be inside the patient's body. For example, the system 205 can be implanted subcutaneously via a vein or artery, via an endoscopic or laparoscopic procedure, and can be inserted orally or surgically. In yet another aspect, the system 205 can be attached externally to the patient's skin. Alternatively, the system 205 can include components inside the patient's body and components outside the patient's body.

[0018] The monitoring and processing system 205 may represent a plurality of monitoring and processing systems 205 that can process the biometric data of a patient in parallel, communicate with each other, and / or communicate with a server via a network. One or two or more systems 205 can acquire or receive all or part of the patient's biometric data (e.g., electrical signals, anatomical images, blood pressure, temperature, blood glucose level, or other biometric data). One or two or more systems 205 can also acquire or receive additional information associated with the patient's biometric data acquired or received from one or more other systems 205. The additional information can be, for example, diagnostic information and / or information obtained from devices such as wearable devices. Each monitoring and processing system 205 can process the data it has acquired and can also process the data received from another system 205.

[0019] The sensor 210 may represent one or two or more sensors configured to sense biometric data from a patient. For example, the sensor 210 can be an electrode configured to acquire an electrical signal (e.g., a bioelectrical signal generated from the heart), a temperature sensor, a blood pressure sensor, a blood glucose sensor, a blood oxygen sensor, a pH sensor, an accelerometer, or a microphone. In one aspect, the system 205 can include an ECG monitoring system that measures an ECG signal generated from the heart. In such a case, the sensor 210 can include one or two or more electrodes configured to acquire the ECG signal. The ECG signal can be used for the diagnosis and treatment of various cardiovascular diseases. In one aspect, the sensor 210 can include a catheter, a probe, a blood pressure cuff, a weighing scale, a bracelet (e.g., a smartwatch biometric tracker), a blood glucose monitor, a continuous positive airway pressure (CPAP) machine, or any other device that provides biometric data or other data related to the health of the patient and can include one or two or more electrodes.

[0020] The transceiver 260 can include a transmitter component and a receiver component. These transmitter and receiver components may be integrated into a single device or implemented separately. The transceiver can provide connectivity between system 205 and other systems or servers via a communication network 270. The network 270 may be a wired network, a wireless network, or may include a combination of wired and / or wireless networks. The network 270 may be a short-range network (e.g., a local area network (LAN) or a personal area network (PAN)). Information can be transmitted or received via a short-range network using various short-range communication protocols such as Bluetooth, Wi-Fi, Zigbee, Z-Wave, near field communication (NFC), ultra-wideband, or infrared (IR). The network 270 may also be a long-range network (e.g., a wide area network (WAN), the Internet, or a cellular network). Information can be transmitted or received via a long-range network using various long-range communication protocols such as TCP / IP, HTTP, 3G, 4G / LTE, or 5G / New Radio.

[0021] Processor 220 may be configured to process, for example, biometric data of a patient acquired by sensor 210 and store the biometric data and / or the processed biometric data in memory 230. Processor 220 may also be configured to transmit the biometric data across network 270 via the transmitter of transceiver 260. Biometric data from one or two or more other monitoring and processing systems 205 may be received by the receiver of transceiver 260. Processor 220 may use an algorithm (e.g., an artificial intelligence-based algorithm such as a machine learning algorithm), or alternatively or in addition, the algorithm may be used by another processor (e.g., in local system 280 or remote system 290). In an aspect, processor 220 can include one or more CPUs, one or more GPUs, or one or more FPGAs. In these aspects, the algorithm may be executed on one or two or more of these processing units. Similarly, processor 220 can include a dedicated ASIC for performing deep learning computations (such as the Intel® Nervana™ Neural Network Processor), and the machine learning algorithm may be executed on such a dedicated ASIC. The processing unit that executes the algorithm may be located in a medical treatment room or another location (e.g., another medical facility or the cloud).

[0022] The input device 240 of the monitoring and processing system 205 may be used as a user interface. The input device 240 can include, for example, a piezoelectric sensor or a capacitive sensor configured to receive user inputs such as taps or touches. Thus, the input device 240 may be configured to implement capacitive coupling in response to a tap or touch by the user on the surface of the system 205. Gesture recognition can be implemented by various capacitive couplings such as resistive capacitive coupling, surface capacitive coupling, projected capacitive coupling, surface acoustic wave coupling, piezoelectric coupling, or infrared touch. A capacitive sensor may be disposed on the surface of the input device 240 such that a tap or touch on the surface activates the system 205. The processor 220 may be configured to selectively respond to different tap patterns of the capacitive sensor (e.g., single tap or double tap on the input device 240) such that different functions of the system 205 (e.g., data acquisition, storage, or transmission) are activated based on the detected pattern. In one aspect, for example, audible feedback can be provided to the user from the system 205 when a gesture is detected and recognized.

[0023] The local system 280, which is communicable with the monitoring and processing system 205 via the network 270, may be configured to function as a gateway to the remote system 290 via another network 285 that may be accessible to the local system 280. The local system 280 can be, for example, a smartphone, a smartwatch, a tablet, or other portable smart device. Alternatively, the local system 280 may be a stationary or stand-alone device. Patient biometric data can be transmitted between the local system 280 and the monitoring and processing system 205. In one aspect, the local system 280 may also be configured to display the acquired patient biometric data and related information.

[0024] The remote system 290 may be configured to receive at least a portion of the biometric data and related information of the monitored patient via a network 285, which may be a long-distance network. For example, if the local system 280 is a mobile phone, the network 285 may be a wireless cellular network, and the information may be transmitted between the local system 280 and the remote system 290 via a wireless technology standard such as any of the above wireless technologies. The remote system 290 may be configured to present the received biometric data and related information of the patient visually on a display or auditorily through a speaker to a medical professional (e.g., a doctor).

[0025] Figures 3, 4, and 5 each show an exemplary catheter 300, 400, 500. Electrodes or sensors disposed on the distal portions of the catheters 300, 400, 500 can be used to obtain electrical signals measured in heart tissue that can be used for anatomical and electrical mapping. Another commonly used multi-electrode mapping catheter is the Pentaray® catheter (not shown). As described above, an additional catheter may be used to obtain a reference signal. Such a reference signal can be used, for example, to temporally correlate signals obtained by a Pentaray® catheter or a balloon catheter 400. Other electrodes or sensors may be used to emit electrical signals to the heart tissue, for example, to facilitate treatment purposes (ablation) and / or catheter positioning.

[0026] FIG. 3 shows a catheter 300 that includes a contact electrode 332 and a non-contact electrode 338. The non-contact electrode can measure a remote field electrical signal within the heart chamber and can be disposed within an array 336 along the longitudinal axis of the distal portion 334 of the catheter 300. The distal portion 334 can further include a position sensor 340 (or a plurality of position sensors) that can generate or measure signals used to determine the position and orientation of the sensor 340. Since there is a fixed spatial relationship between the position sensor 340 and the distal tip 318 and the other electrodes 332, 338, the positions of the distal tip 318 and the other electrodes 332, 338 can be resolved based on the determined position of the position sensor 340. The handle 320 of the catheter 300 can include a control device 346 for steering or deflecting the distal portion 334 or for orienting the distal portion as desired.

[0027] For example, the position sensor 340 can sense an electric field that can be generated by the systems 100, 200 (for the purpose of sensor localization) and can be configured to transmit a signal generated from the sensed electric field through a cable 342 (i.e., the cable 122 shown in FIG. 1) that passes through the catheter 300 to the console 124. In another alternative, the position sensor 340 can transmit a signal to the console 124 via a wireless link. Based on the signal transmitted by the position sensor 340, the processing units 141, 220 can calculate the position and orientation of the distal portion 334 of the catheter 300 and the position and orientation of the distal tip 318 and the other electrodes 332, 338. The calculation of the position and orientation can be performed based on the signal transmitted by the position sensor 340 after the signals are amplified, filtered, digitized, or otherwise processed by the systems 100, 200.

[0028] To acquire electrical activity at points within the heart, catheter 300 can be advanced into the heart, and its distal tip 318 can be brought into contact with the endocardium at a particular tissue location to acquire data at that location. To construct an anatomical and electrical map of the heart, this data acquisition process needs to be repeated for a number of positions within the region of interest. Constructing a detailed map of the region of interest within the heart via such a point-by-point data accumulation process can be time-consuming. To address this drawback, multi-electrode catheters have been developed for simultaneously measuring electrical activity at multiple position points within the heart. The multi-electrode catheter can be implemented using any applicable shape such as a balloon catheter (described with reference to FIG. 4) or a loop catheter (described with reference to FIG. 5).

[0029] FIG. 4 shows an exemplary balloon catheter 400, based on which one or more features of the present disclosure can be implemented. As shown in FIG. 4, balloon catheter 400 can include a plurality of splines such as splines 414, 415, 416. A plurality of electrodes are disposed on each spline such as electrodes 421 - 426 shown in FIG. 4. Balloon catheter 400 can be designed such that when deployed within a patient's body, its electrodes can be held in close contact with the endocardial surface. For example, the balloon catheter can be inserted into a lumen such as a pulmonary vein. The balloon catheter can be inserted into the pulmonary vein in a contracted state, such that the balloon catheter does not occupy its maximum volume during insertion. Subsequently, the balloon catheter may expand while within the pulmonary vein, such that the electrodes on the balloon catheter contact the entire circular portion of the pulmonary vein. Such contact with the entire circular portion of the pulmonary vein or any other lumen can enable measurement of electrical activity from multiple points on the tissue. That is, each acquisition can result in as many activation signals as there are electrodes.

[0030] FIG. 5 shows an exemplary loop catheter 500, based on which one or more features of the present disclosure can be implemented. The loop catheter 500 (also referred to as a lasso catheter) can include a plurality of electrodes 532, 534, 536 that can simultaneously acquire electrical signals measured at the positions of the electrodes when in contact with heart tissue (the endocardial wall). The loop catheter 500 can be wholly or partially elastic so that it can twist, bend, or otherwise change its shape based on the received signals and / or based on the application of an external force (e.g., when pressed against the heart tissue).

[0031] Accordingly, a multi-electrode catheter (such as a Pentaray® catheter, balloon catheter 400, or loop catheter 500) can be advanced into the heart cavity to acquire electrical (activation) signals. A position sensor disposed on the multi-electrode catheter (in a known spatial relationship to the electrodes) can be used by systems 100, 200 to establish the position of each of the electrodes within the heart. The electrical signals measured by each electrode can be recorded and presented to a physician on display 127 by systems 100, 200. For example, the measured electrical signals can be presented as vertically aligned electrograms that are temporally correlated according to a reference signal. Typically, the reference signal is measured by a dedicated reference electrode that can be disposed, for example, in the CS. Therefore, when using a multi-electrode catheter with a plurality of electrodes (each electrode positioned on the endocardial surface), a physician can collect as many activation signals as there are electrodes.

[0032] FIG. 6 illustrates a method 600 for electroanatomical mapping using a multi-electrode mapping catheter 630 and a reference catheter 620, and one or more features of the present disclosure may be implemented based thereon. In the example shown in FIG. 6, catheters 620, 630 include pairs of electrodes 620A, 630A, 630B, 630C, and each pair is configured to measure bipolar beats. The aspects described herein can also be applied when using unpaired electrodes where each electrode is configured to measure a unipolar beat. As shown explicitly, the mapping catheter 630 is placed at a first location 630.1 on the endocardium 610 and then moved to a second location 630.2 on the endocardium. Therefore, the mapping catheter 630 measures activation signals at their respective locations when placed at different locations on the endocardium. That is, at each location, a pair of electrodes measures the depolarization of the tissue at that location (the depolarization caused by the electrical signal 605 propagating through the endocardium 610). The electrical signal 605 can originate in the sinoatrial node (e.g., when caused by a normal heartbeat) or can originate at other locations (e.g., when caused by tachycardia or a pacing catheter). The reference catheter 620 is typically used to measure the activation at a location of tissue near the origin of the electrical signal 605. For example, when the electrical signal 605 originates in the sinoatrial node, the reference catheter 620 can acquire a signal 640 having a normal heartbeat that appears approximately every 500 milliseconds (ms).

[0033] To construct an electroanatomical map, time measurements associated with the activation (or depolarization) of tissue at various locations on the endocardium are collected and must be temporally associated with each other. This has conventionally been done by moving a mapping catheter along a heart tissue of one of the heart cavities while measuring activation signals. For example, a first group 650.1 of activation signals can be measured by the electrodes of a mapping catheter 630.1 when positioned at a first location, and a second group 650.2 of activation signals can be measured by the electrodes of a mapping catheter 630.2 when positioned at a second location. As shown in FIG. 6, each group may include activation signals A, B, and C (e.g., of group 650.1) measured by respective pairs of electrodes A, B, and C (e.g., acquired at the first location of mapping catheter 630.1). To construct a LAT map, a set of time measurements is derived from each group of activation signals. For example, a set of time measurements T A = 10 ms, T B = 12 ms, and T C = 15 ms are derived from groups 650.1 of activation signals A, B, and C, respectively. Also, a set of time measurements T A = 40 ms, T B = 43 ms, and T C = 46 ms are derived from groups 650.2 of activation signals A, B, and C, respectively. As illustrated, these time measurements are derived relative to the beats of a reference signal 640 (acquired by a reference catheter 620) using a reference time T R = 0 ms 642, 644. In this way, one set of measurements (e.g., 650.1 - T A , 650.1 - T B , and 650.1 - T C ) is compared to a second set of measurements (e.g., 650.2 - T A , 650.2 - T B , and 650.2 - T CIn combination with [it], one map can be formed to visualize the electrical signal propagation across the wall of the heart structure (e.g., the left ventricle). However, as described above, the need to use the reference catheter 620 complicates the mapping procedure (and is not feasible in some patients). Next, a method for mapping that does not require the use of the reference catheter 620 will be described with reference to FIGS. 7-9.

[0034] FIG. 7 illustrates an exemplary method 700 for electroanatomical mapping using a multi-electrode mapping catheter, and one or more features of the present disclosure may be implemented based thereon. As illustrated, an electrical signal 705 (equivalent to signal 605) activates the endocardium 710. The activation at the location of the tissue near the origin of the electrical signal 705 is indicated by the activation signal 740. However, in contrast to the method 600 described with reference to FIG. 6, according to this method 700, as will be further described below, there is no need to use this signal 740 as a reference, so there is no need to obtain this signal 740 by a reference catheter (such as catheter 620).

[0035] As illustrated in FIG. 7, during the mapping procedure, the mapping catheter 730 is moved from a first location 730.1 to a second location 730.2 such that at least one spatial overlap exists between the electrodes. That is, in the embodiment of FIG. 7, when the mapping catheter is disposed at the second location 730.2, the electrode pair A is located at the same position 735 where the electrode pair C was located when the catheter was disposed at the first location 730.1. Thus, the activation signal C (of group 750.1) can be associated 755 with the activation signal A (of group 750.2). That is, it can be assumed that their respective time measurements are the same. Therefore, the time measurements from multiple sets can be temporally associated due to the spatial overlap between the electrode pairs (or electrodes when monopolar signals are measured) without using the reference signal 740. For example, the activation signal A of group 750.1 can be used as a reference 752: T A =T R=0 ms. Other time measurement values associated with group 750.1 can be measured relative to that reference, and thus, as illustrated, T B =12 ms and T C =15 ms. Next, regarding the time measurement values of group 750.2, the activation signal C (of group 750.1) and the activation signal A (of group 750.2) are measured by electrode pairs that spatially overlap (electrode pair C of 730.1 and electrode pair A of 730.2, respectively), so their time measurement values are assumed to be close enough, i.e., 15 ms. Using this assumption, the time measurement values of group 750.2 can be associated with the time measurement values of group 750.1. Thus, as illustrated, the time measurement values associated with group 750.2 are T A =15 ms, T B =14 ms + 15 ms = 29 ms, and T C =18 ms + 15 ms = 23 ms. As described above, the roles of groups 750.1 and 750.2 can be interchanged, and it should be noted that any one of the activation signals of the group (750.1 or 750.2) can be used as the reference T R to use.

[0036] In this way, as long as each group of activation signals (associated with each set of time measurement values) includes at least one activation signal measured by an electrode that overlaps an electrode that measured an activation signal of another group, the time measurement values from multiple sets (associated with each respective group of activation signals) can be related, or, in other words, the sets of time measurement values (corresponding to different mapping catheter positions on the endocardium) can be combined. Aspects of method 700 are further described with reference to FIG. 8.

[0037] FIG. 8 illustrates an exemplary method 800 for combining a set of measurements obtained by a mapping catheter, and one or more features of the present disclosure may be implemented based thereon. The concepts illustrated in FIG. 8 are similar to the concepts illustrated in FIG. 7, except that in FIG. 8, the locations of the electrodes of the mapping catheter (or electrode pairs in the case of bipolar) are shown within a two-dimensional (2D) space. For example, when using a multi-electrode mapping catheter such as a Pentaray® catheter or the catheter shown in FIGS. 4 and 5, the same concepts as described herein are applied to the locations of the electrodes within a 3D space, as is actually the case.

[0038] During the mapping procedure, the physician moves the mapping catheter from one position on the heart tissue to another. At each position, the electrodes of the catheter acquire activation signals that can obtain a set of time measurements. Thus, each set of time measurements corresponds to each positioning of the mapping catheter during the mapping procedure. FIG. 8 depicts four sets of time measurements 810, 820, 830, and 840. The first set of measurements 810 is measured by the electrodes at the location represented by the filled circle and is obtained from the activation signal acquired when the catheter was placed at the first position. The second set of measurements 820 is measured by the electrodes at the location represented by the unfilled circle and is obtained from the activation signal acquired when the catheter was placed at the second position. The third set of measurements 830 is measured by the electrodes at the location represented by the diagonally patterned circle and is obtained from the activation signal acquired when the catheter was placed at the third position. Also, the fourth set of measurements 840 is measured by the electrodes at the location represented by the dotted circle and is obtained from the activation signal acquired when the catheter was placed at the fourth position.

[0039] As described with respect to the time measurement value sets of each of the groups 750.1, 750.2 in FIG. 7, four sets 810, 820, 830, 840 of time measurement values can be combined. For example, since these sets are obtained from activation signals acquired by the mapping catheter as the mapping catheter moves along the endocardium, these sets can be combined step by step. For example, starting from set 810, the activation signal measured at electrode location 811 may be selected to provide a time reference T R (e.g., reference 750.1-T in FIG. 7 A 752, etc.). For that time reference, time measurement values associated with activation signals measured at other electrode locations of set 810 are calculated (e.g., as the time measurement values 750.1-T in FIG. 7 B and 750.1-T C were calculated). Time measurement values associated with activation signals measured at electrode locations of the other sets 820 - 840 are calculated based on overlapping electrodes (e.g., as the time measurement values 750.2-T in FIG. 7 A , 750.2-T B and 750.2-T C were calculated). Combining measurement sets 810 - 840 can be done step by step as will be made explicit next.

[0040] In the first stage of the mapping procedure 800A, the activation signal can be measured by the electrodes of the second set 820. The time measurement values of this set 820 can be obtained by combining the set 820 with the set 810 using the first spatial overlap 815 existing between the respective electrodes of the sets 810 and 820. Next, in the second stage of the mapping procedure 800B, the activation signal can be measured by the electrodes of the third set 830. Since there is no spatial overlap between any electrode of the set 830 and any electrode of the other two sets 810 and 820, it cannot be combined with either of the previous sets 810 and 820. However, in the third stage of the mapping procedure 800C where the activation signal can be measured by the electrodes of the fourth set 840, additional spatial overlap can be introduced. For example, a second spatial overlap 825 between the respective electrodes from the sets 810 and 840, a third spatial overlap 835 between the respective electrodes from the sets 830 and 840, and a fourth spatial overlap 845 between the respective electrodes from the sets 820 and 840. Therefore, the time measurement values of the set 840 can be obtained by combining the set 840 with the set 810, the set 820, or the set 830 using the spatial overlaps 825, 845, or 835 respectively. Further, at this stage 800C, the time measurement values of the set 830 can be obtained by combining the set 830 with the set 840 using the third spatial overlap 835. In this way, more sets of measurement values can be combined, and an LAT map can be constructed based on the time measurement values of these sets.

[0041] In practice, and as illustrated in FIG. 8, the spatial overlaps 815, 825, 835, 845 between electrodes may not be perfect. That is, it is difficult for the spatial distance between the overlapping electrodes to become zero. Also, accordingly, the time measurement values calculated based on those overlaps may incorporate errors. Such errors can be cumulative because one set of time measurement values depends on the calculation of another set of time measurement values. One way to reduce the error is to consider the degree of overlap. For example, as shown in the figure, set 840 includes three overlapping electrodes 825, 835, and 845. Thus, in an aspect, based on the degree of overlap, the time measurement value of set 840 is T 825 based on the overlap 825 shown as, T 835 based on the overlap 835 shown as, or T 845 based on the overlap 845 shown as. In another aspect, the time measurement value of set 840 can be calculated based on a weighted combination as follows. T(S = 840)= ω 825 ·T 825 (S)+ ω 835 ·T 835 (S)+ ω 845 ·T 845 (S),(1) where T(S) represents the time measurement value and weight of set S, and the weights ω 825 , ω 835 , ω 845 are proportional to the degree of overlap in the respective spatial overlaps 825, 835, and 845. The degree of overlap can be determined based on the distance between the locations of the overlapping electrodes. For example, a distance below a first threshold (typically limited by the accuracy of the system when positioning the electrodes) can correspond to 100% overlap, while a distance above a second threshold (typically a function of the spatial distance between electrodes within a mapping catheter) can result in 0% overlap.

[0042] In an aspect, M versions of the time measurement values for N sets are

[0043]

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[0048] FIG. 9 is a flowchart of an exemplary method 900 for generating an electroanatomical map of the heart, and one or more features of the present disclosure may be implemented based thereon. Method 900 begins, at step 910, by measuring a group of activation signals. Each group of activation signals may be measured by respective electrodes of a mapping catheter disposed at respective locations within the heart. The mapping catheter may be positioned within the heart such that one or more electrodes that measure one group of activation signals spatially overlap with the respective electrodes that measure other groups of activation signals. In an aspect, the electrodes are determined to overlap if their distance from each other is below a predetermined threshold. At step 920, based on the measured groups of activation signals, respective sets of time measurements may be obtained using overlapping electrodes, as described above with reference to FIGS. 7 and 8. Based on the obtained sets of time measurements, at step 930, an electroanatomical map may be constructed. Further aspects of method 900 are described below.

[0049] In a first aspect, obtaining the first set of time measurements (of the set of time measurements) may be based on the activation signals of respective first groups (of the group of signal activations), where the time measurements are calculated with respect to a time reference provided by the first activation signal of the first group (e.g., time reference 750.1-T provided by activation signal 750.1-A A Time measurement 750.1-T that may be calculated based on 752 B and so on).

[0050] In a second aspect, obtaining the second set of time measurements (of the set of time measurements) may be based on the activation signals of respective second groups (of the group of signal activations), where the time measurements are calculated relative to another time measurement obtained based on the activation signal of another group, and the activation signal of the other group is measured by a first electrode that overlaps the second electrode that measures the activation signal of the second group (e.g., time measurement 750.1-T obtained based on activation signal 750.1-CC The time measurement value 750.2 - T calculated for B etc., and the activation signal 750.1 - C is measured by the electrode 730.2 - C that overlaps the electrode 730.1 - A that measured the activation signal 750.2 - A). It should be noted that in the second aspect, the time measurement value may be adjusted based on the degree of overlap between the first electrode and the second electrode. Furthermore, the certainty metric can be associated with the time measurement value based on such a degree of overlap.

[0051] Therefore, the certainty metric can be calculated for each time measurement value. In an aspect, the certainty metric can be calculated based on the shape of each activation signal. For example, the certainty metric of each time measurement value associated with the location of the electrodes within a small neighborhood can be determined based on the morphological similarity of the monopolar electrical signals measured by those electrodes. Thus, the time measurement values can be filtered based on their respective certainty metrics when constructing an electroanatomical map.

[0052] Although the features and elements have been described above in specific combinations, those skilled in the art will understand that each feature or element can be used alone or in combination with other features and elements. Additionally, although the process steps have been described above in a specific order, the steps can also be performed in other desirable orders.

[0053] The methods, processes, modules, and systems described herein may be implemented in a computer program, software, or firmware incorporated in a computer-readable medium for execution by a computer or processor. Examples of computer-readable media include electronic signals (transmitted via a wired or wireless connection) and computer-readable storage media. Examples of computer-readable storage media include, but are not limited to, read only memory (ROM), random access memory (RAM), registers, cache memory, semiconductor memory devices, magnetic media such as internal hard disks and removable disks, magneto-optical media, and optical media such as CD-ROM disks and digital versatile disks (DVD). A processor associated with the software may be used to implement a radio frequency transceiver for use in a WTRU, UE, terminal, base station, RNC, or any host computer.

[0054] Further embodiments of the present specification can be formed by supplementing one embodiment with one or more elements from any one or two or more other embodiments of the present specification and / or replacing one or more elements from one embodiment with one or more elements from one or two or more other embodiments of the present specification.

[0055] Accordingly, it is understood that the disclosed subject matter is not limited to the specific embodiments disclosed, but is intended to cover all modifications within the spirit and scope of the present disclosure as defined by the appended claims, the above description, and / or the appended drawings.

[0056] 〔Embodiment〕 (1) A method for generating an electroanatomical map of the heart, comprising: Measuring a group of activation signals, wherein the activation signals of each group are measured by respective electrodes of a mapping catheter disposed at respective positions within the heart, Measuring a group of activation signals, wherein at least one electrode of the mapping catheter that measured the activation signals of one group of the groups spatially overlaps with respective electrodes of the mapping catheter that measured the activation signals of another group of the groups; Obtaining respective sets of time measurement values using the overlapping electrodes based on the group of activation signals; Constructing the electroanatomical map based on the obtained sets of time measurement values. A method comprising: (2) The method according to embodiment 1, wherein when the distance between the at least one electrode and the respective electrodes is less than a predetermined threshold, the at least one electrode and the respective electrodes overlap. (3) The obtaining further comprises calculating a first set of time measurement values of the sets based on activation signals of respective first groups of the groups, wherein the time measurement values are calculated with respect to a time reference provided by a first activation signal of the first groups. The method according to embodiment 1. (4) The obtaining further comprises calculating a second set of time measurement values of the sets based on activation signals of respective second groups of the groups, wherein the time measurement values are calculated with respect to another time measurement value obtained based on activation signals of another group, and the activation signals of the another group are measured by a first electrode that overlapped a second electrode that measured the activation signals of the second groups. The method according to embodiment 3. (5) The calculating the second set of the time measurement values further comprises adjusting the second set of the time measurement values based on a degree of overlap between the first electrode and the second electrode. The method according to embodiment 4.

[0057] (6) Further including calculating a certainty metric for each time measurement value of the set of time measurement values, the method according to Embodiment 4. (7) The method according to Embodiment 6, wherein the certainty metric associated with the time measurement values of the second set is calculated based on the degree of overlap between the first electrode and the second electrode. (8) The method according to Embodiment 6, wherein the certainty metric associated with the time measurement values is calculated based on the shape of the activation signal measured by each electrode. (9) Further including filtering each time measurement value of the set of time measurement values based on the certainty metric when constructing the electroanatomical map, the method according to Embodiment 6. (10) Further including: calculating a plurality of versions of each set of the time measurement values, for each version, when calculating the time measurement values of the second set, the other group being a different group of the groups; and predicting the set of time measurement values based on the plurality of versions, the method according to Embodiment 4.

[0058] (11) Further including: calculating a plurality of versions of each set of the time measurement values, for each version, another set of the sets being selected as the first set; and predicting the set of time measurement values based on the plurality of versions, the method according to Embodiment 3. (12) Further including: ​further comprising calculating a second set of time measurement values of the set based on activation signals of each second group of the groups, the time measurement values being calculated based on a weighted combination of time elements, each time element being calculated for a time measurement value calculated based on activation signals of another group, the activation signals of the another group being measured by a first electrode overlapping a second electrode that measured the activation signals of the second group, and a weight associated with the time element being calculated based on a degree of overlap between the first electrode and the second electrode, the method of embodiment 3. (13) A system for generating an electroanatomical map of a heart, at least one processor; a memory storing instructions that, when executed by the at least one processor, cause the system to measure a group of activation signals, each activation signal of the group being measured by a respective electrode of a mapping catheter disposed at a respective location within the heart, measure a group of activation signals, at least one electrode of the mapping catheter that measured the activation signals of one group of the groups being spatially overlapped with respective electrodes of the mapping catheter that measured the activation signals of another group of the groups; obtain respective sets of time measurement values using the overlapping electrodes based on the group of activation signals; construct the electroanatomical map based on the obtained sets of time measurement values. (14) The system of embodiment 11, wherein when a distance between the at least one electrode and the respective electrodes is less than a predetermined threshold, the at least one electrode and the respective electrodes overlap. (15) The obtaining is Further comprising calculating a time measurement value of a first set of the set based on activation signals of each first group of the groups, wherein the time measurement value is calculated with respect to a time reference provided by a first activation signal of the first group, the system according to embodiment 11.

[0059] (16) The obtaining further comprises calculating a time measurement value of a second set of the set based on activation signals of each second group of the groups, wherein the time measurement value is calculated with respect to another time measurement value obtained based on activation signals of another group, and the activation signal of the another group is measured by a first electrode overlapping a second electrode that measures the activation signal of the second group, the system according to embodiment 13. (17) The calculating the time measurement value of the second set further comprises adjusting the time measurement value of the second set based on a degree of overlap between the first electrode and the second electrode, the system according to embodiment 14. (18) The obtaining further comprises calculating a certainty metric for each time measurement value of the set of time measurement values, wherein the certainty metric associated with the time measurement value of the second set is calculated based on a degree of overlap between the first electrode and the second electrode, the system according to embodiment 14. (19) The constructing the electroanatomical map further comprises filtering each time measurement value of the set of time measurement values based on the certainty metric, the system according to embodiment 16. (20) The obtaining further comprises calculating a plurality of versions of each set of the time measurement values, and predicting the set of time measurement values based on the plurality of versions, For each version, when calculating the time measurement values of the second set, whether the other group is a different group among the groups, or The system according to embodiment 14, wherein for each version, another set among the sets is selected as the first set.

[0060] (21) obtaining further comprising calculating time measurement values of a second set among the sets based on activation signals of respective second groups among the groups, the time measurement values being calculated based on a weighted combination of time elements, each time element is calculated for a time measurement value calculated based on an activation signal of another group, the activation signal of the another group being measured by a first electrode overlapping a second electrode that measured the activation signal of the second group, and a weight associated with the time element being calculated based on a degree of overlap between the first electrode and the second electrode, the system according to embodiment 13. A non-transitory computer-readable medium including instructions executable by at least one processor to implement a method for generating an electroanatomical map of a heart, the method comprising: measuring a group of activation signals, each activation signal of the group being measured by a respective electrode of a mapping catheter disposed at a respective position within the heart, measuring a group of activation signals, wherein at least one electrode of the mapping catheter that measured an activation signal of one group among the groups spatially overlaps with respective electrodes of the mapping catheter that measured activation signals of another group among the groups; obtaining respective sets of time measurement values using the overlapping electrodes based on the group of activation signals; constructing the electroanatomical map based on the obtained sets of time measurement values.

Claims

1. A system for generating an electroanatomical map of the heart, comprising: at least one processor; and a memory storing instructions that, when executed by the at least one processor, cause the system to: measure a group of activation signals, wherein each activation signal of each group is measured by a respective electrode of a mapping catheter disposed at a respective location within the heart; measure a group of activation signals such that at least one electrode of the mapping catheter that measured an activation signal of one group of the groups spatially overlaps with each respective electrode of the mapping catheter that measured an activation signal of another group of the groups; obtain respective sets of time measurement values using the overlapping electrodes based on the group of activation signals; and construct the electroanatomical map based on the obtained sets of time measurement values.

2. The system of claim 1, wherein the at least one electrode and each respective electrode overlap when a distance between the at least one electrode and the each respective electrode is below a predetermined threshold.

3. The obtaining further comprises: calculating a first set of time measurement values of the sets based on activation signals of each respective first group of the groups, wherein the time measurement values are calculated with respect to a time reference provided by a first activation signal of the first group.

4. The obtaining further comprises: calculating a second set of time measurement values of the sets based on activation signals of each respective second group of the groups, wherein the time measurement values are calculated with respect to another time measurement value obtained based on an activation signal of another group, and wherein the activation signal of the another group is measured by a first electrode that overlaps a second electrode that measured the activation signal of the second group.

5. The calculating of the second set of time measurement values further comprises: adjusting the second set of time measurement values based on a degree of overlap between the first electrode and the second electrode.

6. The obtaining further comprises: Further comprising calculating a certainty metric for each time measurement value of the set of time measurement values, wherein the certainty metric associated with the time measurement values of the second set is calculated based on the degree of overlap between the first electrode and the second electrode, the system according to claim 2.

7. Said constructing the electroanatomical map being Further comprising filtering each time measurement value of the set of time measurement values based on the certainty metric, the system according to claim 4.

8. Said obtaining being Calculating a plurality of versions of each of the sets of time measurement values; and Predicting the set of time measurement values based on the plurality of versions, For each version, when calculating the time measurement values of the second set, the other group is a different group of the groups, or For each version, another set of the sets is selected as the first set, the system according to claim 2.

9. Said obtaining being Further comprising calculating a second set of time measurement values of the set based on the activation signals of each second group of the groups, the time measurement values being calculated based on a weighted combination of time elements, Each time element is calculated for a time measurement value calculated based on the activation signal of another group, the activation signal of the another group being measured by a first electrode overlapping the second electrode that measured the activation signal of the second group, and the weight associated with the time element is calculated based on the degree of overlap between the first electrode and the second electrode, the system according to claim 1.

10. A non-transitory computer-readable medium comprising instructions executable by at least one processor for implementing a method for generating an electroanatomical map of a heart, the method comprising: Measuring a group of activation signals, wherein the activation signals of each group are measured by respective electrodes of a mapping catheter disposed at respective positions within the heart, Measuring groups of activation signals, wherein at least one electrode of the mapping catheter that measures the activation signal of one of the groups spatially overlaps with each electrode of the mapping catheter that measures the activation signal of another one of the groups; Based on the groups of activation signals, obtaining respective sets of time measurement values using the overlapping electrodes; Constructing the electroanatomical map based on the obtained sets of time measurement values, a non-transitory computer-readable medium. **Claim 11** A method for generating an electroanatomical map of a heart, comprising: Measuring groups of activation signals, wherein the activation signals of each group are measured by respective electrodes of a mapping catheter disposed at respective positions within the heart; Measuring groups of activation signals, wherein at least one electrode of the mapping catheter that measures the activation signal of one of the groups spatially overlaps with each electrode of the mapping catheter that measures the activation signal of another one of the groups; Based on the groups of activation signals, obtaining respective sets of time measurement values using the overlapping electrodes; Constructing the electroanatomical map based on the obtained sets of time measurement values. **Claim 12** The method according to claim 11, wherein the at least one electrode and each of the respective electrodes overlap when a distance between the at least one electrode and each of the respective electrodes is below a predetermined threshold. **Claim 13** The obtaining further comprises: Calculating a first set of time measurement values of the sets based on the activation signals of respective first groups of the groups, wherein the time measurement values are calculated with respect to a time reference provided by a first activation signal of the first groups, the method according to claim 11. **Claim 14** The obtaining comprises: Further comprising calculating a time measurement value of a second set of the set based on activation signals of each second group of the groups, wherein the time measurement value is calculated with respect to another time measurement value obtained based on activation signals of another group, and the activation signals of the another group are measured by a first electrode overlapping a second electrode that measured the activation signals of the second group, the method according to claim 13.

15. Said calculating of the time measurement value of the second set The method according to claim 14, further comprising adjusting the time measurement value of the second set based on a degree of overlap between the first electrode and the second electrode.

16. Said obtaining The method according to claim 14, further comprising calculating a certainty metric for each time measurement value of the set of time measurement values.

17. The method according to claim 16, wherein the certainty metric associated with the time measurement value of the second set is calculated based on a degree of overlap between the first electrode and the second electrode.

18. The method according to claim 16, wherein the certainty metric associated with the time measurement value is calculated based on a shape of activation signals measured by respective electrodes.

19. Said constructing of the electroanatomical map The method according to claim 16, further comprising filtering each time measurement value of the set of time measurement values based on the certainty metric.

20. Said obtaining Calculating a plurality of versions of each set of the time measurement values, wherein for each version, when calculating the time measurement value of the second set, the another group is a different group of the groups, and calculating a plurality of versions; and Predicting the set of time measurement values based on the plurality of versions, the method according to claim 14.

21. Said obtaining Calculating a plurality of versions of each set of the time measurement values, wherein for each version, another set of the sets is selected as the first set, and calculating a plurality of versions; and Predicting the set of time measurement values based on the plurality of versions, the method according to claim 13.

22. It should be remembered that further comprising calculating a time measurement value of a second set of the set based on activation signals of each second group of the groups, the time measurement value being calculated based on a weighted combination of time elements, each time element being calculated for a time measurement value calculated based on activation signals of another group, the activation signals of the another group being measured by a first electrode overlapping a second electrode that measured the activation signals of the second group, and a weight associated with the time element being calculated based on a degree of overlap between the first electrode and the second electrode, the method according to claim 13.

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