Mapping of local activation times during sinus and non-sinus cardiac cycles

Abstract

The present invention is entitled "Mapping Local Activation Times of Sinus and Non-Sinus Cardiac Cycles". The present invention discloses a method comprising receiving multiple sets of signals during multiple cardiac cycles, each set of signals indicating, for a probe inserted into a cardiac chamber, the 3D position of the distal end of the probe, the potential measured at that position, and the corresponding time at which the potential was measured during a given cycle. The received measurements and corresponding times are compared with a first template for sinus rhythm cycles and a second template for non-sinus rhythm cycles to identify a sequence of cycles comprising a consecutive first cycle, a second cycle, and a third cycle, wherein the first cycle and the second cycle match the first template, and the third cycle matches the second template. A physical map is generated based on the positions. Based on the received positions and the corresponding potentials, an electroanatomical map comprising the local activation times of the non-sinus rhythm cycles superimposed on the physical map is rendered to a display.

Description

Technical Field

[0001] The present invention relates generally to cardiac mapping, and in particular to mapping local activation times of sinus rhythm and non-sinus rhythm cardiac cycles. Background Art

[0002] Arrhythmias, such as atrial fibrillation, are heart rhythms that produce irregular heartbeats. Arrhythmias typically occur when an area of ​​heart tissue abnormally conducts electrical signals to adjacent tissue, disrupting the normal heartbeat cycle and causing an irregular heartbeat.

[0003] Mapping electrical potentials in the heart is a common tool for diagnosing and treating cardiac arrhythmias. Typically, time-varying electrical potentials in the endocardium are sensed and recorded according to location within the heart, and this time-varying potential is then used to map local electrograms or local activation times. Due to the time required for electrical impulses to conduct through the myocardium, the activation times vary from point to point in the endocardium. The direction of this electrical conduction at any point in the heart is conventionally represented by an activation vector, which is perpendicular to the isoelectric activation wavefront, both of which can be derived from a map of activation times. The propagation rate of this activation wavefront through any point in the endocardium can be represented as a velocity vector.

[0004] Mapping the activation wavefront and conduction field helps physicians identify and diagnose abnormalities such as ventricular and atrial tachycardias and ventricular and atrial fibrillation due to areas of impaired electrical propagation in cardiac tissue.

[0005] U.S. Patent Application 2015 / 0073246 to Chmiel et al. describes a method for manually mapping premature ventricular contractions (PVCs). The method involves recording a series of electrocardiogram (ECG) signals from a patient with PVCs, and then selecting, by a physician, beats that indicate sinus rhythm and beats that indicate PVCs. The sinus beats are used to generate a physical map of the heart. Electrophysiological readings of local activation time (LAT) obtained during PVC beats are then superimposed on the sinus map, generating a so-called LAT hybrid map.

[0006] US Patent No. 5,271,411 issued to Ripley et al. describes a method for ECG signal analysis and arrhythmia detection. The method includes identifying a normal QRS complex and labeling a QRS complex acquired after the normal QRS complex is identified based on a plurality of rules and their corresponding positions.

[0007] U.S. Patent No. 4,336,810 issued to Anderson et al. describes a method for arrhythmia analysis of ECG recordings. The method includes receiving an ECG signal and comparing it to a known template based on the classification of previously identified wave complexes. Based on the comparison, each of the received signals can be designated as normal, ventricular ectopy, supraventricular ectopy, or unknown (ectopy of unknown origin).

[0008] U.S. Patent Application 2012 / 0165895 to Dong et al. describes a method for non-capturing intrinsic discrimination in cardiac pacing response classification. The method includes distinguishing non-capturing intrinsic beats during evoked response detection and classification by comparing features of a post-pacing cardiac signal with expected features associated with a non-capturing response having intrinsic activation. In some embodiments, detection of a non-capturing response with intrinsic activation can be based on peak amplitude and timing of the cardiac signal.

[0009] U.S. Patent Application 2009 / 0099468 to Thiagalingam et al. describes a method for automatically processing electrophysiological data. The method includes determining temporal locations by defining one or more reference channels containing reference beats and comparing beats in recorded electrogram data to the defined one or more reference channels. An index of the temporal locations and other information of the beats within the recorded electrogram data is created, and the index of temporal locations can be used to analyze the recorded electrogram data to locate electrophysiological features suggestive of abnormalities. Summary of the Invention

[0010] According to an embodiment of the present invention, a method is provided, which includes: receiving, by a processor, multiple sets of signals during multiple cardiac cycles, each set of signals indicating, for a medical probe inserted into a cardiac chamber, a three-dimensional (3D) position of a distal end of the probe, an electric potential measured at the 3D position, and a corresponding time at which the electric potential was measured during a given cardiac cycle; comparing the received electric potential measurements and corresponding times with a first template for a sinus rhythm cardiac cycle and a second template for a non-sinus rhythm cardiac cycle to identify a cardiac cycle sequence comprising a consecutive first cardiac cycle, a second cardiac cycle, and a third cardiac cycle, wherein the first cardiac cycle and the second cardiac cycle conform to the first template, and the third cardiac cycle conforms to the second template; generating a physical map of the cardiac chamber based on the 3D position; and rendering an electroanatomical map to a display based on the received 3D position and the corresponding measured electric potential, the electroanatomical map including local activation times of non-sinus rhythm cardiac cycles superimposed on the physical map.

[0011] In some embodiments, the probe comprises an intracardiac catheter having a plurality of electrodes that simultaneously generate corresponding sets of signals.

[0012] In other embodiments, the non-sinus rhythm cardiac cycle comprises premature ventricular contractions.

[0013] In another embodiment, generating the physical map includes generating the physical map based on 3D locations indicated by multiple sets of signals received during a first cardiac cycle and a second cardiac cycle. In one embodiment, generating the physical map includes generating a first physical map based on 3D locations indicated by multiple sets of signals received during the first cardiac cycle, generating a second physical map based on 3D locations indicated by multiple sets of signals received during the second cardiac cycle, and selecting the first physical map or the second physical map. In another embodiment, the second physical map conforms to the first physical map.

[0014] In a supplemental embodiment, rendering an electroanatomical map comprising local activation times of non-sinus rhythm cardiac cycles superimposed on a physical map includes superimposing the local activation times of the non-sinus rhythm cardiac cycles indicated by each given signal at a map location corresponding to a 3D location indicated by the given signal.

[0015] In some embodiments, comparing the received electrical potential measurements and corresponding times to a given template includes comparing a given signal indicative of the received electrical potential measurements and corresponding times to a given template.

[0016] In further embodiments, the method may include identifying a region of the map having an earliest local activation time and marking the identified region for ablation on a display. In one embodiment, identifying the region of the map having the earliest local activation time includes segmenting the map into a plurality of regions based on their respective local activation times and identifying the region having the earliest local activation time.

[0017] According to an embodiment of the present invention, a device is also provided, which includes a display and a processor, which is configured to: receive multiple sets of signals during multiple cardiac cycles, for a medical probe inserted into a cardiac chamber, each set of signals indicates the three-dimensional (3D) position of the distal end of the probe, the electric potential measured at the 3D position, and the corresponding time when the electric potential was measured during a given cardiac cycle; compare the received electric potential measurement results and corresponding times with a first template of a sinus rhythm cardiac cycle and a second template of a non-sinus rhythm cardiac cycle to identify a cardiac cycle sequence including a consecutive first cardiac cycle, a second cardiac cycle, and a third cardiac cycle, wherein the first cardiac cycle and the second cardiac cycle conform to the first template, and the third cardiac cycle conforms to the second template; generate a physical map of the cardiac chamber based on the 3D position; and render an electroanatomical map to the display based on the received 3D position and the corresponding measured electric potential, the electroanatomical map including the local activation time of the non-sinus rhythm cardiac cycle superimposed on the physical map.

[0018] According to an embodiment of the present invention, there is also provided a computer software product operating in conjunction with a medical probe for insertion into a body cavity, the product comprising a non-transitory computer-readable medium having program instructions stored therein, wherein the instructions, when read by a computer, cause the computer to: receive a plurality of sets of signals during a plurality of cardiac cycles, wherein, for a medical probe inserted into a cardiac cavity, each set of signals indicates a three-dimensional (3D) position of a distal end of the probe, an electrical potential measured at the 3D position, and a corresponding time at which the electrical potential was measured during a given cardiac cycle; compare the received electrical potential measurements and the corresponding times with the sinusoidal position; The present invention relates to a method for detecting a cardiac cycle comprising: comparing a first template of a sinus rhythm cardiac cycle with a second template of a non-sinus rhythm cardiac cycle to identify a cardiac cycle sequence including a consecutive first cardiac cycle, a second cardiac cycle, and a third cardiac cycle, wherein the first cardiac cycle and the second cardiac cycle conform to the first template, and the third cardiac cycle conforms to the second template; generating a physical map of the cardiac chamber based on the 3D position; and rendering an electroanatomical map to a display based on the received 3D position and the corresponding measured potential, the electroanatomical map including activation times of the non-sinus rhythm cardiac cycles superimposed on the physical map. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The present disclosure is herein described, by way of example only, with reference to the accompanying drawings, in which:

[0020] Figure 1A and Figure 1B is a schematic illustration of a medical system including a mapping catheter according to an embodiment of the present invention;

[0021] Figure 2 is a schematic illustration of a distal end of a mapping catheter according to an embodiment of the present invention;

[0022] Figure 3 A flowchart schematically illustrating a method of performing a mapping procedure using a mapping catheter to generate a map of a cardiac chamber based on signals collected during sinus and non-sinus cardiac cycles according to an embodiment of the present invention;

[0023] Figure 4 is a schematic detail view of the distal end of a mapping catheter in a cardiac chamber during a mapping procedure according to an embodiment of the present invention;

[0024] Figure 5 is a schematic diagram of an electrocardiogram during sinus and non-sinus cardiac cycles according to an embodiment of the present invention; and

[0025] Figure 6 is a schematic diagram of an electroanatomical map including first local activation times of a sinus rhythm cardiac cycle and second local activation times of a non-sinus rhythm cardiac cycle superimposed on a physical map of a cardiac chamber, according to an embodiment of the present invention. DETAILED DESCRIPTION

[0026] Generating a local activation time (LAT) map of a heart with an arrhythmia is typically a difficult and time-consuming process. LAT maps are generated from information collected during sinus and non-sinus cardiac cycles, and selecting different types of cardiac cycles (also called beats) by a medical professional (e.g., a physician) can be time-consuming.

[0027] Embodiments of the present invention provide methods and systems for automatically generating an electroanatomical LAT hybrid map for mapping premature ventricular contractions (PVCs) in an arrhythmic heart. As described below, an intracardiac probe is inserted into a cardiac chamber and multiple sets of signals are received over multiple cardiac cycles, each set of signals indicating the three-dimensional (3D) position of the distal tip of the probe, an electrical potential measured at the 3D position, and the corresponding time during a given cardiac cycle when the potential was measured.

[0028] The received potential measurements and corresponding times are compared with a first template of a normal sinus rhythm (also referred to herein as sinus rhythm) cardiac cycle and a second template of a non-sinus rhythm cardiac cycle to identify a sequence of cardiac cycles comprising a first cardiac cycle, a second cardiac cycle, and a third cardiac cycle in succession, wherein the first cardiac cycle and the second cardiac cycle conform to the first template and the third cardiac cycle conforms to the second template. A physical map of the cardiac chamber is generated based on the received 3D position, and an electroanatomical map including local activation times of non-sinus rhythm cardiac cycles superimposed on the physical map is rendered to a display based on the received 3D position and the corresponding measured potentials. The resulting map can then be used to select an area for ablation because it indicates the origin of the PVC. Using templates to identify sinus and non-sinus cardiac cycles enables a system implementing an embodiment of the present invention to quickly generate an electroanatomical LAT map of an arrhythmic heart without requiring any user input to identify sinus and non-sinus cardiac cycles. In some embodiments, a physical map can be generated based solely on 3D coordinates received during the first and second cardiac cycles (i.e., sinus rhythm cardiac cycles). By using only 3D position coordinates collected from sinus rhythm cardiac cycles, embodiments of the present invention can produce a more stable physical map with fewer errors due to the unstable or "jumpy" nature of adjacent non-sinus cardiac cycles (such as PVCs).

[0029] System Description

[0030] Figure 1A and Figure 1B is a schematic illustration of a medical system 20 including a medical probe 22 and a console 24 according to an embodiment of the present invention, and Figure 2 is a schematic illustration of the distal end 26 of a medical probe 22 according to an embodiment of the present invention. The medical system 20 may be based on, for example, a device manufactured by Biosense Webster Inc. of 33 Technology Drive, Irvine, CA 92618 USA. In the embodiments described below, the medical probe 22 can be used for diagnostic or therapeutic treatments, such as for mapping electrical potentials in the heart 28 of a patient 30. In the embodiments described herein, the medical probe 22 can also be referred to as a mapping catheter. Alternatively, the medical probe 22 can be used, mutatis mutandis, for other therapeutic and / or diagnostic purposes in the heart or other body organs.

[0031] During a medical procedure, the medical professional 34 inserts the medical probe 22 into the biocompatible sheath 80 ( Figure 2), the sheath has been pre-positioned in a body cavity of the patient (e.g., a chamber of the heart 28) so that the distal end 26 of the medical probe enters the body cavity. By way of example, Figure 2 As shown, the distal end 26 of the probe 22 includes flexible splines 82 formed at the end of a tubular shaft 86. During a medical procedure, the medical professional 34 can deploy the splines 82 by extending the tubular shaft from the sheath 80.

[0032] The console 24 is connected to body surface electrodes, typically comprising an adhesive skin patch 36, attached to the patient 30, via cables 32. The console 24 includes a processor 38 that, in conjunction with a current tracking module 40, determines the positional coordinates of the distal end 26 within the heart 28 based on the impedance measured between the adhesive skin patch 36 and electrodes 84 attached to the splines 82, as shown. Figure 2 In the embodiments described herein, the electrodes 84 may also be configured to apply a signal to tissue in the heart 28 and / or measure a physiological property (e.g., local surface potential) at a location in the heart. The electrodes 84 are connected to the console 24 via wires (not shown) extending through the medical probe 22.

[0033] Although the embodiments herein show a variety of intracardiac catheters such as NAV catheter probe 20, but other multi-electrode intracardiac catheters such as Catheters are considered to be within the spirit and scope of the present invention. NAV catheter and Both catheters were manufactured by BiosenseWebster Inc.

[0034] The processor 38 may include a real-time noise reduction circuit 42, typically configured as a field programmable gate array (FPGA), followed by an analog-to-digital (A / D) ECG (electrocardiogram) signal conversion integrated circuit 44. The processor may pass signals from the A / D ECG circuit 42 to another processor and / or may be programmed to execute one or more algorithms disclosed herein, each of which includes the steps described below. The processor uses circuits 42 and 44, as well as features of the modules described in more detail below, to execute one or more algorithms.

[0035] Figure 1A 、 Figure 1B and Figure 2The medical system shown in uses impedance-based sensing to measure the position of the distal end 26, but other position tracking techniques (e.g., techniques using magnetic-based sensors) may be used. Impedance-based position tracking techniques are described, for example, in U.S. Patents 5,983,126, 6,456,864, and 5,944,022, the disclosures of which are incorporated herein by reference. Magnetic position tracking techniques are described, for example, in U.S. Patents 5,391,199, 5,443,489, 6,788,967, 6,690,963, 5,558,091, 6,172,499, and 6,177,792, the disclosures of which are incorporated herein by reference. The method of position sensing described above is described in the above The invention is implemented in the system and is described in detail in the patent cited above.

[0036] The console 24 also includes an input / output (I / O) communication interface 46 that enables the console to transmit signals from and / or to the electrodes 84 and the adhesive skin patch 36. Based on the signals received from the electrodes 84 and / or the adhesive skin patch 36, the processor 38 can generate an electroanatomical local activation time (LAT) map 48 that presents measurements of cardiac conduction velocity, as described below with reference to Figure 5 As described in the description.

[0037] During the procedure, the processor 38 can present the electroanatomical LAT map 48 to the medical professional 34 on a display 50 and store data representing the electroanatomical LAT map in a memory 52. ​​The memory 52 can include any suitable volatile and / or non-volatile memory, such as random access memory or a hard drive. In some embodiments, the medical professional 34 can manipulate the map 48 using one or more input devices 54. In alternative embodiments, the display 50 can include a touch screen that can be configured to accept input from the medical professional 34 in addition to presenting the map 48.

[0038] like Figure 1B As shown, the memory 52 stores signals 60 received by the processor 38, each given signal 60 comprising an ordered pair of a sampling time 61 indicating when the given signal was received and an electrical potential 62 measured by the adhesive skin patch 36 or a given electrode 84, as described below. Figure 1B6, signal 60 and its corresponding sampling time 61 and potential 62 are distinguished by adding a letter after the identifying number, so that the signal includes signals 60A-60C, the sampling time includes sampling time 61A-61C, and the potential includes potential 62A-62C. In the embodiment described herein, signal 60A includes a surface ECG signal received from patch 36, signal 60B includes a position signal received from patch 36 and indicating the corresponding position 63 of electrode 84, and signal 60C includes an intracardiac ECG signal received from electrode 84.

[0039] exist Figure 1B In the configuration shown, the memory 52 also stores a set of electrode location records 64, a set of intracardiac ECG records 65, and a set of ECG templates 66. Each electrode location record 64 includes an electrode identifier (ID) 67 indicating a given electrode 84, a set of location signals 60B received from the adhesive skin patch 36 for the given electrode, and a set of locations 63 having a one-to-one correspondence with the electrode 84. Each given location 63 generally includes a set of 3D coordinates generated from its corresponding electrical potential 62B.

[0040] In some embodiments, the electrode location records 64 have a one-to-one correspondence with the electrodes 84 , and the processor 38 may initialize the set of electrode location records 64 by storing a unique numeric value or text string indicating the corresponding electrode 84 with each electrode ID 67 .

[0041] Each intracardiac ECG record 65 includes an electrode ID 68 that indicates a given electrode 84, and a set of intracardiac ECG signals 60C received from the indicated electrode. In some embodiments, the intracardiac ECG records 65 have a one-to-one correspondence with the electrodes 84, and the processor 38 can initialize the set of intracardiac ECG records 65 by storing a unique numeric value or text string indicating the corresponding electrode 84 in each electrode ID 68.

[0042] Each ECG template 66 includes a cardiac cycle type 69 and a corresponding set of template ECG signals 70, each of which includes time 71 and potential 72. Examples of cardiac cycle types 69 include, but are not limited to, normal sinus rhythm and non-sinus rhythm such as premature ventricular contractions (PVCs).

[0043] In operation, the processor 38 may receive the signal 60 and store the received signal to the memory 52 using the following implementation:

[0044] Processor 38 receives a set of body surface ECG signals 60A from adhesive skin patch 36 and stores the received set of body surface ECG signals to memory 52 .

[0045] The processor 38 receives a corresponding set of position signals 60B for each electrode 84 from the adhesive skin patch 36. Upon receiving a given set of position signals 60B for a given electrode 84, the processor 38 may use the above-described embodiments to calculate the positions 63 corresponding to the potentials 62B in the given set of position signals 60B. The processor 38 may then identify a given electrode position record 64 whose electrode ID 67 indicates the given electrode and store the given set of position signals 60B and the corresponding positions 63 in the identified electrode position record.

[0046] The processor 38 receives a corresponding set of intracardiac ECG signals 60C from the electrodes 84. Upon receiving each given set of intracardiac signals 60C from a given electrode 84, the processor 38 may identify a given intracardiac ECG record 65 whose electrode ID 69 indicates the given electrode and store the given set of intracardiac ECG signals 60C to the identified intracardiac ECG record.

[0047] The console 24 may also include an electrocardiogram (ECG) module 56 that may be configured to generate an ECG graph 58 from the surface ECG signal 60A. In some embodiments, the processor 38 presents the ECG graph 58 on the display 50 (i.e., along with the LAT map 48). In addition to presenting the ECG graph 58 on the display 50, the processor 38 may also store the ECG graph in the memory 52. ​​Additional details of the ECG graph 58 are provided below with reference to FIG. Figure 5 Described in the description.

[0048] Mapping

[0049] Figure 3 is a flow chart schematically illustrating a method for mapping chambers of the heart 28 according to an embodiment of the present invention, and Figure 4 Detailed schematic diagram of spline 82 engaging endocardial tissue 110 in a chamber according to an embodiment of the present invention. In loading step 90, processor 38 loads a plurality of templates 60 into memory 52, the plurality of templates including at least one template 60 for a cardiac cycle in sinus rhythm and at least one template 60 for a cardiac cycle in non-sinus rhythm.

[0050] In an inserting step 92, the medical professional 34 inserts the distal end 26 into the chamber so that the splines 82 engage the intracardiac tissue 110, and in a manipulating step 94, the medical professional 34 moves the splines at the distal end along the intracardiac tissue 110 during a plurality of cardiac cycles. As the medical professional 34 moves the splines along the intracardiac tissue during a plurality of cardiac cycles, in a receiving step 96, the processor 38 receives the surface ECG signal 60A, the position signal 60B, and the intracardiac ECG signal 60C.

[0051] In an identification step 98, the processor 38 identifies three consecutive cardiac cycles, including two sinus rhythm cardiac cycles followed by a non-sinus rhythm cardiac cycle, by comparing the received surface ECG signal 60A with the ECG template 66. In some embodiments, comparing the surface ECG signal 60A with the template 66 includes comparing the sampling time 61A and the potential 62A in the surface ECG signal with the time 71 and the potential 72 in the template.

[0052] As described above, a first given template 66 can be defined for a sinus rhythm cardiac cycle, and a second given template 66 can be defined for a non-sinus rhythm cardiac cycle, such as a premature ventricular contraction. In an embodiment of the present invention, the processor 38 can identify three cardiac cycles by comparing the surface ECG signal 60A with the templates 66, detecting that the surface ECG signal matches the first given template 66 for a sinus rhythm cardiac cycle during the first two cardiac cycles, and detecting that the surface ECG signal matches the second given template 66 for a non-sinus rhythm cardiac cycle during the subsequent third cardiac cycle. Thus, the processor 38 can identify a first set of sampling times 61 for the first two cardiac cycles and a second set of sampling times 61 for the third cardiac cycle.

[0053] To match the surface ECG signal 60A with a given template 66 during a given cardiac cycle, the processor 38 may perform a correlation between the surface ECG signal and the given template and detect a match by comparing the correlation with a predefined threshold and determining that there is a high correlation (i.e., within the defined threshold) between the surface ECG signal and the given template. For example, when comparing the surface ECG signal 60A with the given template 66 for a non-sinus rhythm cardiac cycle, the processor 38 may use a correlation threshold of 0.95, and when comparing the surface ECG signal with the given template 62 for a sinus rhythm cardiac cycle, the processor 38 may use a correlation threshold of 0.9.

[0054] Figure 5 1 is a schematic illustration of an ECG chart 58 according to an embodiment of the present invention. The ECG chart 58 includes a trace including a line 120 that plots the potential 61A of a given set of body surface ECG signals 60A along a vertical axis 122 relative to time along a horizontal axis 124, where the potential 61A is measured as a voltage V and time is measured in seconds S. Figure 5 In the example shown, line 120 shows potentials 61A in a given set of surface ECG signals 60A measured during a series of consecutive cardiac cycles 126, 128, and 130, where cardiac cycles 126 and 128 are sinus rhythm, and where cardiac cycle 130 includes a premature ventricular beat (i.e., an example of a non-sinus rhythm cardiac cycle).

[0055] Returning to the flowchart, in a first generation step 100, the processor 38 generates a physical map of the cardiac chamber based on the 3D coordinates indicated by the position 63. Figure 6 In some embodiments, processor 38 uses the 3D coordinates indicated by positions 63 of position signal 60B from its corresponding sampling times 61B during two sinus rhythm cardiac cycles to create a more stable physical map (i.e., ignoring the 3D coordinates indicated by positions 63 of position signal 60B from its corresponding sampling times 61B during non-sinus rhythm cardiac cycles), as described above.

[0056] Using a physical map that includes 3D coordinates indicated by positions 63 of position signals 60B from their corresponding sampling times 61B during normal sinus rhythm cardiac cycles can help create a more useful physical map because the heart 28 is typically in sinus rhythm most of the time. For example, during an ablation procedure using an ablation catheter (not shown), if a non-sinus cardiac cycle includes PVCs, the heart 28 will typically be in sinus rhythm with intermittent short PVC pulse trains. Therefore, if the processor 38 creates a physical map using 3D coordinates indicated by positions 63 of position signals 60B from their corresponding sampling times 61B during PVC cardiac cycles, there may be differences between the positions of the points of the map (PVC geometry) and the distal end 26 because the position of the ablation catheter is primarily shown in sinus rhythm. Therefore, any ablation area may not be optimal for correcting the patient's arrhythmia. It is believed that the geometry of the heart is different during sinus rhythm than its geometry during non-sinus cardiac cycles such as PVCs.

[0057] In another embodiment, the processor 38 may generate a physical map by creating a first physical map for the 3D coordinates indicated by the positions 63 of the position signal 60B from its corresponding sampling times 61B during a first (i.e., sinus rhythm) cardiac cycle, creating a second physical map for the 3D coordinates indicated by the positions 63 of the position signal 60B from its corresponding sampling times 61B during a second (i.e., sinus rhythm) cardiac cycle, and selecting either the first physical map or the second physical map as the physical map. Figure 6 The physical map is described in the description of .

[0058] In some embodiments, the processor 38 may generate a physical map only if the surface ECG signal 60A at its respective sampling times 61A during the first and second sinus rhythm cardiac cycles matches (i.e., within a specified threshold) a given template 66 of sinus rhythm cardiac cycles. In other words, the processor 38 may generate a physical map only if the first and second maps are substantially identical (i.e., consistent with each other).

[0059] In a second generation step 102, processor 38 generates a map 48 that includes local activation times for non-sinus rhythm cardiac cycles superimposed on a physical map based on positions 63 (i.e., as indicated in the position signal) and corresponding electrical potentials 62C measured by electrodes 84 (i.e., as indicated in the intracardiac ECG signal). (U.S. Patent Application 2015 / 0073246, the disclosure of which is incorporated herein by reference, describes superimposing PVC electrical data on a sinus rhythm physical map.) In other words, map 48 reflects the geometry of heart 28 during sinus rhythm, but with the local activation times of the heart when experiencing PVCs.

[0060] Finally, in a rendering step 104, the processor 38 renders the map 48 to the display 50, and the method ends. To render the map 48, the processor 38 may render the physical map 140 on the display 50 and superimpose the local activation times of the non-sinus rhythm cardiac cycles indicated by each given intracardiac ECG signal 60C on the physical map rendered on the display at the map positions corresponding to the positions indicated by the corresponding position signals (i.e., the positions where the sampling time 61B and the sampling time 61C match). Examples of superimposing the local activation times on the physical map are described below with reference to Figure 6 Described in the description.

[0061] Figure 6 is a schematic illustration of a cross-section of the LAT map 48 showing a physical map 140 comprising chambers of the heart 28, according to an embodiment of the present invention. Figure 6 1 , the local activation time information of the map 48 is incorporated into the physical map 140 and encoded using patterns according to a legend 142. These patterns mimic the pseudo-coloring of an actual functional map. The patterns in the legend 142 correspond from left to right to the range of LAT early to LAT late times (i.e., relative to a reference time for a given cardiac cycle).

[0062] Thus, in map 48, first region 144 has a relatively early LAT and is surrounded by region 146 having a relatively late local activation time. In the embodiments described herein, regions 144 and 146 comprise map locations corresponding to 3D locations indicated by received signals. In operation, processor 38 can identify and mark region 144 (i.e., the region in map 48 having the earliest LAT) as a region for ablation due to region 144. Alternatively, a medical professional can use input device 54 to select and mark regions 144 and / or 146.

[0063] It should be understood that the above embodiments are cited by way of example only, and the present invention is not limited to what has been specifically shown and described hereinabove. On the contrary, the scope of the present invention includes combinations and subcombinations of the various features described above, as well as variations and modifications thereof, which will occur to those skilled in the art upon reading the above description and which are not disclosed in the prior art.

Claims

1. A method for mapping local activation times of sinus and non-sinus cardiac cycles, the method comprising: receiving, by a processor, a plurality of sets of signals during a plurality of cardiac cycles, each set of signals indicating, for a medical probe inserted into a cardiac chamber, a three-dimensional position of a distal tip of the probe, an electrical potential measured at the three-dimensional position, and a corresponding time during a given cardiac cycle at which the electrical potential was measured; comparing the received electrical potential measurements and the corresponding times to a first template of sinus rhythm cardiac cycles and a second template of non-sinus rhythm cardiac cycles to identify a sequence of cardiac cycles comprising a first cardiac cycle, a second cardiac cycle, and a third cardiac cycle in succession, wherein the first cardiac cycle and the second cardiac cycle conform to the first template and the third cardiac cycle conforms to the second template; generating a physical map of the cardiac chamber based on the three-dimensional position; as well as rendering an electroanatomical map to a display based on the received three-dimensional positions and corresponding measured electrical potentials, the electroanatomical map including the local activation times of the non-sinus rhythm cardiac cycle superimposed on the physical map, Wherein generating the physical map comprises generating the physical map based on the three-dimensional positions indicated by the plurality of sets of signals received during the first cardiac cycle and the second cardiac cycle. 2 . The method of claim 1 , wherein the probe comprises an intracardiac catheter having a plurality of electrodes that simultaneously generate corresponding sets of the signals.

3. The method of claim 1, wherein the non-sinus rhythm cardiac cycle comprises a premature ventricular contraction.

4. The method of claim 1 , wherein generating the physical map comprises: Generating a first physical map based on the three-dimensional positions indicated by the multiple sets of signals received during the first cardiac cycle, and generating a second physical map based on the three-dimensional positions indicated by the multiple sets of signals received during the second cardiac cycle; and selecting the first physical map or the second physical map. The method of claim 4 , wherein the second physical map conforms to the first physical map.

6. The method of claim 1 , wherein rendering the electroanatomical map including the local activation times of the non-sinus rhythm cardiac cycle superimposed on the physical map comprises: The local activation time of the non-sinus rhythm cardiac cycle indicated by each given signal is superimposed at a map position corresponding to the three-dimensional position indicated by the given signal.

7. The method of claim 1 , wherein comparing the received potential measurements and the corresponding times to a given template comprises: A given signal indicative of the received potential measurements and the corresponding times is compared to the given template.

8. The method of claim 1 and comprising identifying a region of the map having an earliest local activation time and marking the identified region for ablation on the display.

9. The method of claim 8, wherein identifying the region of the map having the earliest local activation time comprises: The map is segmented into a plurality of regions based on their respective local activation times, and the region having the earliest local activation time is identified.

10. An apparatus for mapping local activation times of sinus and non-sinus cardiac cycles, the apparatus comprising: monitor; as well as a processor configured to: receiving a plurality of sets of signals during a plurality of cardiac cycles, each set of signals indicating, for a medical probe inserted into a cardiac chamber, a three-dimensional position of a distal tip of the probe, an electrical potential measured at the three-dimensional position, and a corresponding time during a given cardiac cycle at which the electrical potential was measured, comparing the received electrical potential measurements and the corresponding times to a first template of sinus rhythm cardiac cycles and a second template of non-sinus rhythm cardiac cycles to identify a sequence of cardiac cycles comprising a first cardiac cycle, a second cardiac cycle, and a third cardiac cycle in succession, wherein the first cardiac cycle and the second cardiac cycle conform to the first template and the third cardiac cycle conforms to the second template, generating a physical map of the cardiac chamber based on the three-dimensional position, and An electroanatomical map is rendered to the display based on the received three-dimensional positions and corresponding measured electrical potentials, the electroanatomical map including the local activation times of the non-sinus rhythm cardiac cycle superimposed on the physical map, wherein the processor is configured to generate the physical map by generating the physical map based on the three-dimensional positions indicated by the multiple sets of signals received during the first cardiac cycle and the second cardiac cycle.

11. The apparatus of claim 10, wherein the probe comprises an intracardiac catheter having a plurality of electrodes that simultaneously generate corresponding sets of the signals.

12. The apparatus of claim 10, wherein the non-sinus rhythm cardiac cycles include premature ventricular contractions.

13. The apparatus according to claim 10, wherein the processor is configured to generate the physical map by: generating a first physical map based on the three-dimensional positions indicated by the multiple sets of signals received during the first cardiac cycle, and generating a second physical map based on the three-dimensional positions indicated by the multiple sets of signals received during the second cardiac cycle; and selecting the first physical map or the second physical map. The apparatus of claim 13 , wherein the second physical map conforms to the first physical map.

15. The apparatus of claim 10 , wherein the processor is configured to render the electroanatomical map including the local activation times of the non-sinus rhythm cardiac cycles superimposed on the physical map by superimposing the local activation times of the non-sinus rhythm cardiac cycles indicated by each given signal at a map position corresponding to the three-dimensional position indicated by the given signal.

16. The apparatus of claim 10, wherein the processor is configured to compare the received electrical potential measurements and the corresponding times with a given template, comprising comparing a given signal indicative of the received electrical potential measurements and the corresponding times with the given template.

17. The apparatus of claim 10, wherein the processor is further configured to identify a region of the map having an earliest local activation time and mark the identified region for ablation on the display.

18. The apparatus of claim 17, wherein the processor is configured to identify the region of the map having the earliest local activation time by segmenting the map into a plurality of regions based on respective local activation times of the regions, and identifying the region having the earliest local activation time.

19. A computer software product operating in conjunction with a medical probe for insertion into a body cavity, the product comprising a non-transitory computer-readable medium having program instructions stored therein, the instructions, when read by a computer, causing the computer to: receiving a plurality of sets of signals during a plurality of cardiac cycles, each set of signals indicating, for a medical probe inserted into a cardiac chamber, a three-dimensional position of a distal tip of the probe, an electrical potential measured at the three-dimensional position, and a corresponding time during a given cardiac cycle at which the electrical potential was measured; comparing the received electrical potential measurements and the corresponding times to a first template of sinus rhythm cardiac cycles and a second template of non-sinus rhythm cardiac cycles to identify a sequence of cardiac cycles comprising a first cardiac cycle, a second cardiac cycle, and a third cardiac cycle in succession, wherein the first cardiac cycle and the second cardiac cycle conform to the first template and the third cardiac cycle conforms to the second template; generating a physical map of the cardiac chamber based on the three-dimensional position; as well as rendering an electroanatomical map to a display based on the received three-dimensional positions and corresponding measured electrical potentials, the electroanatomical map including activation times of the non-sinus rhythm cardiac cycles superimposed on the physical map, Wherein generating the physical map comprises generating the physical map based on the three-dimensional positions indicated by the plurality of sets of signals received during the first cardiac cycle and the second cardiac cycle.

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