Pacing mapping of ventricular tachycardia (vt) with direction vector indication

Abstract

A system includes a catheter, an electrocardiogram (ECG) system, and a processor. The catheter is configured to apply pacing to a given tissue location inside a ventricle of a heart of a patient. The ECG system is configured to acquire a set of ECG signals generated in response to the pacing, wherein electrodes of the ECG system attached to the patient define respective directions in space with respect to an origin located in the heart. The processor is configured to (i) compute a set of respective signal differences between the acquired set of ECG signals and a reference set of ECG signals, (ii) compute a set of corresponding deviation vectors along the respective directions in the space, the deviation vectors having magnitudes corresponding to the respective signal differences, (iii) using the deviation vectors, compute a direction vector from the given location to a new ventricle location at which to apply the pacing, and (iv) indicate the computed direction vector to a user.

Description

Technical Field

[0001] This disclosure relates generally to electrophysiological (EP) signals, and more specifically to the assessment of electrical propagation in the heart. Background Technology

[0002] Electrophysiological signal estimation for determining the location of ventricular arrhythmias has been previously proposed in patent literature. For example, U.S. Patent Application Publication 2024 / 0374199 describes a method that includes receiving cardiac signals from multiple locations within the ventricles of a patient's heart. The received signals are compared with a reference signal indicating an arrhythmia. Based on this comparison, a direction toward a location that demonstrates an increased correlation between the received signal and the reference signal is calculated. This direction is then indicated to the user.

[0003] This disclosure will be more fully understood through the following detailed description of embodiments thereof, taken in conjunction with the accompanying drawings, in which: Attached Figure Description

[0004] Figure 1 This is a schematic illustration of a catheter-based electrophysiological (EP) pacing, mapping, and ablation system according to an example of this disclosure; Figure 2A and Figure 2B These are examples based on this disclosure. Figure 1 Lateral and sagittal views of the orientation of the 12-ECG electrode relative to the interior of the heart; Figure 3 It is based on the example from this disclosure. Figure 1 Graphs of the reference set and acquisition set of the EP signal of the 12-ECG electrode; Figure 4 It is based on the examples of this disclosure. Figure 1 A schematic illustration of the layout of the deviation vector derived from the pacing data acquired by the system, which is used to guide the user to the left ventricular (LV) arrhythmogenic region; and Figure 5 This is a flowchart describing a method for guiding a clinician to an arrhythmia-causing location at the left ventricular ventricular fossa using data acquired from an ECG system, according to an example of this disclosure. Detailed Implementation

[0005] Overview To characterize arrhythmias in cardiac chambers such as the left ventricle (LV), physicians can use catheters to perform pacing at multiple LV tissue locations (e.g., applying a bipolar pacing signal between two adjacent catheter electrodes) to search for suspicious tissue pathways and circuits within the LV. If a transient arrhythmogenic event, such as ectopic beats, premature beats, or ventricular premature beats (PVCs), is induced during pacing, the event can be recorded using a 12-lead ECG device, displaying the abnormal signal pattern.

[0006] Various methods can be used to identify arrhythmogenic events induced at a given ventricular location. For example, a processor can perform pattern matching (e.g., pattern matching of 12-lead ECG waveforms) between acquired waveforms and stored pattern waveform characteristics of arrhythmias (e.g., VT, PVC) to identify correlations. High correlation indicates that the pacing location is part of arrhythmogenic tissue.

[0007] Physicians often struggle to determine the direction in which to move the catheter to obtain meaningful high correlations. Therefore, the traditional process of acquiring good-quality data and finding meaningful correlations involves attempting pacing at multiple tissue locations, a workflow that may be difficult to execute in real-world clinical settings.

[0008] Some examples of this disclosure described below provide a technique for calculating and displaying directional arrows on a cardiac mapping (e.g., an EP mapping) after one or more pacing instances to guide the operator toward the optimal location for the next pacing and / or to arrhythmogenic tissue region. The size of the displayed arrows indicates the distance from the current pacing location and the next optimal pacing location and / or arrhythmogenic tissue region.

[0009] The directional arrows in 3D space are directly derived from a scaled difference vector in 3D space, which is extracted using mathematical calculations to correlate the waveform acquired from a 12-lead ECG with the characteristics of a reference 12-lead ECG waveform for the arrhythmia. The disclosed technique provides clinicians with a simplified workflow to identify VT target locations with a minimal number of pacing steps during clinical procedures. This workflow significantly increases the efficiency and accuracy of VT pacing mapping.

[0010] In one example, a method is provided that includes sending a pacing signal to a catheter and, in response, receiving an ECG signal from a 12-lead recorder. The correlation level between the received ECG signal and an ECG reference signal indicating an arrhythmia is calculated. A set of amplitude deviation vectors in 3D space for a given amplitude (e.g., given in mV) is calculated between each received ECG signal and the corresponding reference ECG signal (e.g., at the peak of the received ECG signal). The direction of each amplitude deviation vector is set according to the directionality of the position of each corresponding ECG lead relative to the heart.

[0011] Sum of all magnitude deviation vectors (e.g.) Figure 4 The difference vector (shown) is given. The resulting difference vector points in the correct direction for VT focusing, or at least to the next ventricular position recommended for pacing. This direction is indicated by an arrow on the cardiac mapping, which guides the operator where to adjust the catheter position for the next pacing. The size of the arrow shown depends on the magnitude of the difference vector (a larger size indicates a larger catheter movement required in the specified direction).

[0012] Refresh the arrow with an additional pacing step until the arrow is small enough to determine (e.g., graphically indicated on a mapping map) that the target region has been reached and / or the calculated correlation is high enough (e.g., above a predefined threshold).

[0013] In another example, the time difference (in milliseconds) between each current ECG signal and a reference ECG signal (e.g., between the peak value of the current ECG signal and the peak value of the reference signal) is calculated. This time difference is also used as the magnitude of a directional 3D vector between a given origin location in the heart and the location of each ECG lead. The difference vector is determined by summing all the time difference vectors. The resulting difference vector also points in the correct direction for VT focusing.

[0014] In another example, the difference vector is calculated by weighted summation of all amplitude deviation vectors or time difference vectors. The weights are derived, either through modeling or empirical derivation, to reflect the geometry of the 12 leads and the anatomy of the heart, thereby improving the accuracy of the difference vector and subsequently the accuracy of the guide arrows presented to clinicians.

[0015] System Description Figure 1 This is a schematic illustration of a catheter-based electrophysiological (EP) pacing, mapping, and ablation system 10 according to an example of this disclosure.

[0016] System 10 includes catheter 14, which is percutaneously inserted by physician 24 through the patient's vascular system into the left ventricle (LV) 33 of the heart 12 of patient 23 via a sheath. Catheter 14, as shown herein, is configured for unipolar or bipolar pacing. Physician 24 contacts the distal end assembly 28 of catheter 14 against the heart wall to perform pacing localization in a given area of ​​LV 33.

[0017] As shown in Illustration 45, the distal end assembly 28 carries several electrodes 26 for pacing and optionally for electroablation of LV 33 wall tissue found to be arrhythmic.

[0018] The catheter 14 may further carry a magnetic position sensor that operates together with a positioning pad 25, which includes a plurality of magnetic coils 32 configured to generate a magnetic field in a predefined workspace. The real-time position of the distal end 28 of the catheter 14 can be tracked based on the magnetic field generated by the positioning pad 25 and sensed by the magnetic position sensor. Details of the magnetic position sensing technology are described in U.S. Patents Nos. 5,5391,199, 5,443,489, 5,558,091, 6,172,499, 6,239,724, 6,332,089, 6,484,118, 6,618,612, 6,690,963, 6,788,967, and 6,892,091.

[0019] System 10 includes one or more electrode patches 38 positioned to contact the skin of patient 23 to establish a position reference for impedance-based tracking of positioning pad 25 and electrodes 26. For impedance-based tracking, current is directed toward electrodes 26 and sensed at the electrode skin patch 38, allowing triangulation of the position of each electrode via the electrode patch 38. Details of the impedance-based positioning tracking technique are described in U.S. Patents 7,536,218, 7,756,576, 7,848,787, 7,869,865, and 8,456,182.

[0020] Recorder 11 displays cardiac signals 21 (e.g., an electrogram from a 12-lead ECG device 35 acquired using surface ECG electrodes 18). Recorder 11 may include pacing capabilities for pacing rhythms and / or may be electrically connected to a separate pacemaker.

[0021] The patient interface unit (PIU) 30 is an interface configured to establish electrical communication between the catheter, electrophysiological equipment, power supply, and workstation 55 to control the operation of system 10 and to receive EP signals or apply pacing signals from the catheter. The electrophysiological equipment of system 10 may include, for example, multiple catheters, positioning pads 25, surface ECG electrodes 18, electrode patches 38, ablation energy generator 50, and recorder 11. Optionally and preferably, the PIU 30 further has processing capabilities for real-time calculation of catheter position and for performing ECG calculations.

[0022] Workstation 55 includes memory 57, a processor 56 unit with a memory or storage device in which appropriate operating software is loaded, and user interaction capabilities. Workstation 55 may provide a variety of functions, optionally including: (i) three-dimensional (3D) modeling of the endocardial anatomy and rendering the model or anatomical mapping 20 for display on display device 27; (ii) displaying, on display device 27, activation sequences (or other data) compiled from recorded cardiac signals 21, on representative visual markers or images superimposed on the rendered anatomical mapping 20; (iii) displaying the real-time position and orientation of multiple catheters within the cardiac chambers; and (iv) displaying sites of interest on display device 27, such as where ablation energy has been applied. A commercial product embodying the elements of system 10 could be CARTO. ™ 3 System was purchased from Biosense Webster, Inc., 31A Technology Drive, Irvine, CA 92618.

[0023] exist Figure 1 In the pacing LV tissue location 66A, catheter 14 was used. The obtained ECG signal showed too low a correlation with the reference signal, meaning that location 66A was not the VT-induced arrhythmia site; i.e., correlation alone was insufficient for the physician to continue pacing. Using the disclosed technique, based on the ECG signal set acquired at location 66A and the reference signal (e.g., ...), ... Figure 3 The direction vector 128 is calculated using the signal (the map 20). The scaled direction vector 128, overlaid on the mapping map 20, guides the clinician 24 (e.g., physician 24) to move the catheter 14 in the correct direction. In the example shown, vector 128 points to an LV tissue location 66B that should be more arrhythmogenic (and therefore produce a higher relevance indication (166)). It is also possible that location 66B is actually the target location, in which case the physician 24 may ablate the area around location 66B.

[0024] In some examples, processor 56 typically includes a general-purpose computer programmed in software to perform the functions described herein. This software may be downloaded to the computer electronically via a network, or alternatively or additionally located and / or stored on a non-transitory tangible medium, such as magnetic storage, optical storage, or electronic storage.

[0025] System 10 may include an ablation energy generator 50 adapted to conduct ablation energy to one or more electrodes at the distal end of a catheter configured for ablation. The energy generated by the ablation energy generator 50 may include, but is not limited to, radio frequency (RF) energy or pulsed field ablation (PFA) energy (including monopolar or bipolar high-voltage DC pulses to be used to achieve irreversible electroporation (IRE), or combinations thereof.

[0026] For ablation, the physician 24 similarly guides the distal end of the ablation catheter to the target site. One or more additional catheters may be inserted via a sheath. These catheters may include catheters for sensing intracardiac electrogram signals, catheters dedicated to ablation, and / or catheters dedicated to both EP mapping and ablation.

[0027] This configuration of System 10 is illustrated by way of example to illustrate certain problems solved by the examples of this disclosure and to demonstrate the application of these examples in enhancing the performance of such systems. However, the examples of this disclosure are by no means limited to this particular category of example systems, and the principles described herein can be similarly applied to other categories of medical systems. For example, other catheter types, such as LASSO, can be used. ™ A catheter or basket-shaped catheter.

[0028] VT pacing mapping with direction vector indication Figure 2A and Figure 2B These are, respectively, positions 101 relative to the interior of the heart 12 according to examples of this disclosure. Figure 1 The lateral view 202 and sagittal view 204 of the orientation 210 of the 12-ECG electrode 18. The lateral plane and sagittal plane respectively define the xy plane and xz plane of the XYZ system 102 with mutually orthogonal axes (also in... Figure 3 (As shown). In system 102, the orientation of the ECG electrodes positioned on the patient's torso is defined relative to the location origin 101.

[0029] As shown in Figure 2, although the 12 axes of the 12-ECG leads are not designed to span the entire 3D space, they do span the ventricles in directions such as... Figure 1 The direction of the vector 128 is useful. For example... Figure 4As described above, this crossing is derived by projecting the ECG signal difference onto direction 210. Therefore, this technique achieves... Figure 4 The 12 deviation vectors 118 are derived from the aforementioned scaled difference vector 128, and then the difference vector is presented as a pacing guide arrow on the cardiac mapping 20 of the ventricle.

[0030] Figure 3 Reference set 301 and references obtained during the VT event according to the example of this disclosure are from... Figure 1 The EP signal acquisition of the 12-ECG electrode 18 is shown in graph 302 (set 303). Using an identical set of electrodes 18 attached to the patient's skin, in... Figure 1 Set 303 is acquired during the diagnostic phase (pacing) as described in the text. The difference in line shape between set 301 and set 303 reflects the fact that set 303 is acquired when pacing is removed from the location of the arrhythmogenic tissue region (e.g., normal tissue is being paced).

[0031] The disclosed technique quantifies the difference in signals in the form of amplitudes of 304 (e.g., given in mV). These amplitudes can be viewed as quantifying the degree of difference between the acquired signal and the corresponding reference signal at a given electrode 18. As shown in the figure, some amplitudes of 304 are smaller, while others are larger. (See below...) Figure 4 An amplitude of 304 is used to calculate the corresponding amplitude deviation vector set 118 in 3D space.

[0032] Figure 4 It is based on the examples of this disclosure. Figure 1 A schematic illustration of the layout of the deviation vector 118 derived from the pacing data acquired by the system, which is used to guide the user to the left ventricular (LV) arrhythmia-inducing region; Figure 4 Some ECG electrodes 18 are shown, wherein electrodes 18A-E are located on the front of the patient (e.g., chest 15), and electrodes 18F-G are located on the side or back of the patient.

[0033] As described above, direction 210 can be defined in system 102 along the XYZ axes from origin 101 to each electrode 18. Using Figure 3 The amplitude is 304, and the processor calculates (112) the amplitude deviation vector 118A-E (shown by way of example, where in practice, all 12 vectors are calculated). The weighted sum (120) of the amplitude deviation vector 118A-E gives the scaling direction vector. 128 , in, It is electrode 18 i The weight, i =1, 2, ..., 12, The corresponding value is 304, and 210 is from the origin 101 to each electrode 18 i The direction. It is the difference vector 118(i), and It is the scaling factor described below. The inventors discovered that: using To generate sufficiently accurate direction vectors for all weights 128. However, another weight will be assigned to electrode 18. It can further improve accuracy.

[0034] Scaling factor of vector 128 in units of [cm / mV] This allows vector 128 to be displayed on mapping diagram 20 as an arrow between the current pacing position 66A and the next recommended pacing position 66B. Scaling factor The typical size falls within the range of 0.5-2 [cm / mV]. Arrows are shown on the cardiac mapping 20 to guide the physician 24.

[0035] Pacing mapping method for VT with direction vector indication Figure 5 This is a flowchart describing a method for guiding a clinician toward the location of an LV-induced arrhythmia using data acquired by an ECG system 11, according to an example of this disclosure. As described above, each electrode 18 of the ECG system 11 attached to the patient is spatially oriented 210 relative to the origin 101 located in the heart.

[0036] According to the example presented, the algorithm performs the following process, which begins at catheter insertion step 502, by inserting the pacing catheter 14 into the ventricle 33 of the heart 12.

[0037] Next, at pacing step 504, system 10 uses catheter 14 electrodes to pace a given tissue location inside the ventricle.

[0038] At signal receiving step 506, system 10 receives the corresponding ECG signal from the body surface electrode 18 in response to pacing.

[0039] Next, at amplitude calculation step 508, processor 56 calculates the corresponding signal difference set 304 between the acquired ECG signal set 303 and the reference ECG signal set 301. The processor inserts the amplitude (i.e., the measured signal minus the corresponding reference signal) into the vector equation of the algorithm.

[0040] At the deviation vector calculation step 510, the processor 56 calculates the corresponding deviation vector set 118 along the corresponding direction 210 in space, which has the calculated magnitude 304.

[0041] At direction vector calculation step 512, the processor uses the deviation vector to calculate the scaled direction vector 128 from the given position 66A to the new ventricular position 66B to be paced.

[0042] At arrow presentation step 514, the processor displays the calculated scaling direction vector 128 on cardiac mapping 20 of at least a portion of the ventricle.

[0043] Figure 5 The flowchart is given by way of example. For example, additional steps, such as uploading the weight set from memory 57, may be included. And the scaling factor C, used to calculate the direction vector 128, is omitted for simplicity.

[0044] Example Example 1 A system (10) includes a catheter (14), an electrocardiogram (ECG) system (35), and a processor (56). The catheter is configured to apply pacing to a given tissue location within the ventricle of the heart (12) of a patient (23). The ECG system is configured to acquire a set of ECG signals (303) generated in response to the pacing, wherein electrodes (18) of the ECG system (35) attached to the patient define a corresponding orientation (210) in space relative to an origin (101) located in the heart. The processor is configured to (i) calculate a set of corresponding signal differences (304) between the acquired set of ECG signals (303) and the reference set of ECG signals (301), (ii) calculate a set of corresponding deviation vectors (118) along the corresponding direction (210) in space, the deviation vectors having an amplitude corresponding to the corresponding signal difference (304), (iii) use the deviation vectors (118) to calculate a direction vector (128) from a given position (66A) to a new ventricular position (66B) to which pacing is to be applied, and (iv) indicate the calculated direction vector (128) to the user.

[0045] Example 2 The system (10) according to claim 1, wherein the processor (56) is configured to calculate the direction vector (128) by performing a weighted summation on the deviation vector (118).

[0046] Example 3 The system (10) according to claim 1, wherein the signal difference (304) is one of the following: amplitude difference and time difference.

[0047] Example 4 The system (10) according to claim 1, wherein the ECG system (35) is a 12-lead ECG system.

[0048] Example 5 The system (10) according to claim 1, wherein the origin (101) is one of: (i) the sinoatrial node (SA) and (ii) the given tissue location (66A) where the pacing is applied.

[0049] Example 6 The system (10) according to claim 1, wherein the same electrodes (18) of the ECG system (35) are used to obtain the acquired ECG signal set (303) and the reference ECG signal set (301).

[0050] Example 7 The system (10) according to claim 1, wherein the processor (56) is further configured to indicate the calculated direction vector (128) to a user by displaying the calculated direction vector (128) on a cardiac mapping (20) of at least a portion of the ventricle.

[0051] Example 8 The system (10) according to claim 1, wherein the processor (56) is further configured to indicate the new ventricular position (66B) as an arrhythmogenic position if the magnitude of the direction vector (128) is less than a predefined size.

[0052] Example 9 One method involves applying pacing to a given tissue location within the ventricle of a patient's heart (12) using a catheter (14). An electrocardiogram (ECG) system (35) is used to acquire a set of ECG signals (303) generated in response to pacing, wherein electrodes (18) attached to the patient's ECG system define a corresponding orientation (210) in space relative to an origin (101) located in the heart. A corresponding set of signal differences (304) is calculated between the acquired set of ECG signals (303) and a reference set of ECG signals (301). A corresponding set of deviation vectors (118) along the corresponding orientation (210) in space is calculated, the deviation vectors having amplitudes corresponding to the corresponding signal differences. A direction vector (128) is calculated using the deviation vectors from a given location (66A) to a new ventricular location (66B) where pacing is to be applied. The calculated direction vector (128) is indicated to the user.

[0053] It should be understood that the above embodiments are cited by way of example, and this disclosure is not limited to the content specifically shown and described above. Rather, the scope of this disclosure includes combinations and sub-combinations of the various features described above, as well as variations and modifications thereof, which should be apparent to those skilled in the art upon reading the above description, and which are not disclosed in the prior art.

Claims

1. A system comprising: A catheter configured to apply pacing to a given tissue location within the ventricle of a patient's heart; An electrocardiogram (ECG) system configured to acquire a set of ECG signals generated in response to the pacing, wherein electrodes of the ECG system attached to the patient define a corresponding orientation in space relative to an origin located in the heart; and Processor, the processor being configured to: Calculate the corresponding signal difference set between the acquired ECG signal set and the reference ECG signal set; Calculate the set of corresponding deviation vectors along the corresponding directions in space, the deviation vectors having amplitudes corresponding to the corresponding signal differences; Using the deviation vector, calculate the direction vector from the given location to the new ventricular location where the pacing is to be applied; and Indicate the calculated direction vector to the user.

2. The system according to claim 1, wherein, The processor is configured to calculate the direction vector by performing a weighted summation on the deviation vector.

3. The system according to any one of claims 1 to 2, wherein, The signal difference is one of the following: amplitude difference and time difference.

4. The system according to any one of claims 1 to 2, wherein, The ECG system is a 12-lead ECG system.

5. The system according to any one of claims 1 to 2, wherein, The origin is one of the following: (i) the sinoatrial node (SA) and (ii) the given tissue location where the pacing is applied.

6. The system according to any one of claims 1 to 2, wherein, The acquired ECG signal set and the reference ECG signal set were obtained using the same electrodes of the ECG system.

7. The system according to any one of claims 1 to 2, wherein, The processor is further configured to indicate the calculated direction vector to the user by displaying the calculated direction vector on a cardiac mapping of at least a portion of the ventricle.

8. The system according to any one of claims 1 to 2, wherein, The processor is further configured to indicate the new ventricular position as an arrhythmogenic position if the magnitude of the direction vector is less than a predefined size.

9. A method comprising: Using a catheter to apply pacing to a given tissue location inside the ventricle of the patient's heart; An electrocardiogram (ECG) system is used to acquire a set of ECG signals generated in response to the pacing, wherein the electrodes of the ECG system attached to the patient define a corresponding orientation in space relative to the origin located in the heart; Calculate the corresponding signal difference set between the acquired ECG signal set and the reference ECG signal set; Calculate the set of corresponding deviation vectors along the corresponding directions in space, the deviation vectors having amplitudes corresponding to the corresponding signal differences; Using the deviation vector, calculate the direction vector from the given location to the new ventricular location where the pacing is to be applied; and Indicate the calculated direction vector to the user.

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