Local ECG annotation visualization

Abstract

To perform electrophysiological measurement.SOLUTION: Methods and systems for electrophysiological measurement involve obtaining signals that indicate cardiac electrical activity by using electrodes in contact with the body tissues of a living patient. These signals are then processed to identify local activation times at the electrodes. The identified local activation times are displayed as traces representing the signals over time on a display screen. The brightness of specific trace segments within a designated time window, encompassing the identified local activation times, may be increased relative to segments outside the time window. The method provides flexibility in signal acquisition, allowing the use of intracardiac electrogram signals acquired within the heart or electrocardiogram signals acquired from the body surface. This method enhances visibility and enables efficient analysis of cardiac activity traces for diagnostic and monitoring purposes.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] (CROSS-REFERENCE TO RELATED APPLICATIONS) This application claims the benefit of U.S. Provisional Patent Application No. 63 / 448,415, filed February 27, 2023, the disclosure of which is incorporated herein by reference.

[0002] FIELD OF THE INVENTION FIELD OF THE DISCLOSURE The present disclosure relates to electrophysiological measurements, and in particular to the display of electrophysiological signals. [Background technology]

[0003] Electrophysiological measurements from human tissue can provide important diagnostic information regarding the condition of the tissue. For example, signals indicative of cardiac electrical activity in the human heart are typically recorded by measurement electrodes and analyzed to measure the local activation time (LAT) of the cardiac tissue at each electrode. The signal traces can be visually presented to clinicians as electrograms. Annotation points representing LAT can be automatically marked by overlaying an icon on the visual display of each electrogram. Clinicians can utilize LAT, along with other characteristics of electrograms, in assessing the condition of the cardiac tissue.

[0004] The present disclosure will be more fully understood from the following detailed description of the embodiments thereof, taken in conjunction with the drawings in which: Summary of the Invention [Means for solving the problem]

[0005] According to disclosed embodiments of the present invention, a method, apparatus, and computer-readable medium for electrophysiological measurements includes acquiring signals indicative of cardiac electrical activity from electrodes in contact with bodily tissue of a living patient. These acquired signals are then processed to identify local activation times in one or more of the electrodes. Another aspect may include displaying a trace representing the signal on a display screen as a function of time. In some aspects, the intensity of a segment of the trace within a specified duration window that includes the identified local activation time may be increased relative to a portion of the trace outside the time window.

[0006] Further aspects of the method include acquiring the signal by receiving an intracardiac electrogram signal acquired within the patient's heart or an electrocardiogram signal acquired from the patient's body surface. In some aspects, the specified duration of the time window ranges from 10 ms to 100 ms. Additionally, in one aspect, the system and method may ensure that the trace displayed on the screen is presented without overlaying icons representing local activation times. [Brief explanation of the drawings]

[0007] [Figure 1] 1 illustrates an exemplary catheter-based electrophysiological mapping and ablation system, according to one example of the present disclosure. [Figure 2] 1 is a plot that schematically illustrates identification of annotation points in an electrophysiological signal, according to an example of the present disclosure. [Figure 3] FIG. 1 is a schematic diagram of a display including a highlighted segment of a recorded electrogram, according to an example of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0008] Overview Measuring local activation time (LAT) in cardiac tissue is useful, for example, in estimating electrical conduction velocity (CV) in cardiac tissue and in identifying arrhythmias and other pathologies. Local activation times can be automatically identified using digital signal processing techniques and may be graphically indicated by marking annotation points on electrogram signal traces. Various algorithms may be used to select annotation points in unipolar, bipolar, or multipolar electrogram signals. For example, annotation points may indicate the time points at which the time derivative of the signal reaches its lowest negative value.

[0009] In many systems, signals received by the electrodes are presented on a display screen in the form of multiple parallel traces as a function of time. Each annotation point is marked on the respective signal trace by an icon, such as a large dot. While icons are useful for drawing the clinician's attention to differences in LAT between electrodes, they tend to obscure the form and quality (morphology) of the signal around the annotation point. Therefore, icons can make it difficult for clinicians to see and assess the clinically significant details in the electrogram morphology.

[0010] There is a need for a mode of electrophysiological signal processing and display that can automatically identify and visually present annotations to a clinician without compromising the visibility of the signal trace's morphology. The present disclosure addresses this need by displaying a signal such that segments of the trace that fall within a time window of specified duration that includes each annotation point are displayed with increased brightness relative to portions of the trace outside the time window. Thus, the segments of the signal within the time window can be displayed without overlaying icons that mark the annotation points on the trace. The brightened trace highlights local activation times without cluttering the signal segments around each annotation point, thus drawing the clinician's attention to these segments and enhancing the clinician's recognition of the signal's morphology.

[0011] The examples described below relate particularly to the processing and display of intracardiac electrograms. Alternatively, the principles of the present disclosure may be applied to other electrophysiological signals, particularly signals generated by the heart, such as electrocardiogram signals acquired from the body surface.

[0012] System Description FIG. 1 illustrates an exemplary catheter-based electrophysiology mapping and ablation system 20 according to one example of the present disclosure. The system 20 may include multiple catheters that are percutaneously inserted by a physician 22 through the vascular system of a patient 23 and into a cavity or vasculature of a heart 24. Typically, a delivery sheath (not shown) is inserted into the left or right atrium near a desired location in the heart 24. One or more catheters 26 may then be inserted through the delivery sheath to reach a desired location within the heart 24. The multiple catheters may include catheters dedicated to sensing intracardiac electrogram (IEGM) signals, catheters dedicated to ablation, and / or catheters used for both sensing and ablation. The distal portion of the catheter 26 in the illustrated example includes a basket assembly 28. The physician 22 can manipulate the catheter 26 to position the basket assembly 28 in contact with the heart wall to sense a target site within the heart 24 and / or ablate tissue at the target site.

[0013] Catheter 26 is an exemplary catheter including multiple electrodes 30 distributed across multiple spines 32 in basket assembly 28 and configured to sense IEGM signals and / or ablate cardiomyocytes. Catheter 26 further includes one or more position sensors 34 embedded in a distal portion of the catheter for tracking the position and orientation of basket assembly 28, as described further below. For example, position sensor 34 may include a magnetic position sensor including three magnetic coils for sensing three-dimensional (3D) position and orientation.

[0014] The magnetic position sensor 34 may operate in conjunction with a location pad 36 that includes a plurality of magnetic coils 38 configured to generate a magnetic field within a predetermined working volume that includes the heart 24. The position of the basket assembly 28 of the catheter 26 may be tracked based on the magnetic field generated by the location pad 36 and sensed by the magnetic position sensor 34 (which may include three orthogonal coils). Details of magnetic position sensing techniques that may be applied for this purpose are described, for example, in U.S. Patent Nos. 55,391,199; 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.

[0015] The multiple catheters may also include a reference catheter 39 that is percutaneously inserted by physician 22 through the vascular system of patient 23. Physician 23 contacts an electrode at the distal end (not shown) of reference catheter 39 with the coronary sinus of heart 24 of patient 23. Reference catheter 39 is typically left in place for the duration of the procedure and provides a reference timing signal to which LAT measurements made by catheters 26 are referenced.

[0016] System 20 optionally includes one or more electrode patches 40 positioned for skin contact on patient 23 to establish a position reference for location pads 36 and impedance-based tracking of electrodes 30. For impedance-based tracking, current is directed to electrodes 30 and sensed at electrode patches 40, allowing the position of each electrode 30 to be triangulated via electrode patches 40. Details of impedance-based position tracking techniques are described in U.S. Patent Nos. 7,536,218; 7,756,576; 7,848,787; 7,869,865; and 8,456,182.

[0017] Recorder 42 records and displays electrograms 44 captured by body surface ECG electrodes 46 and intracardiac electrograms (IEGMs) captured by electrodes 30 of catheter 26. Recorder 42 may include pacing capability for pacing the cardiac rhythm and / or may be electrically connected to a stand-alone pacer.

[0018] System 20 may include an ablation energy generator 48 to provide ablation energy to one or more of electrodes 30. The energy generated by ablation energy generator 48 may include, but is not limited to, radiofrequency (RF) energy or pulsed field ablation (PFA) energy, including unipolar or bipolar high-voltage DC pulses, such as may be used to effect irreversible electroporation (IRE), or a combination thereof.

[0019] A patient interface unit (PIU) 50 includes an interface for electrical communication between the catheters 26, other electrophysiology equipment, a power source, and a workstation 52 that controls the operation of the system 20. The electrophysiology equipment in the system 20 may include, for example, multiple catheters 26 (including catheters with other types of distal assemblies and electrode arrays than basket catheters), location pads 36, body surface ECG electrodes 46, electrode patches 40, an ablation energy generator 48, and a recorder 42. Optionally, the PIU 50 further includes processing capabilities for implementing real-time calculations of catheter position and processing ECG signals.

[0020] The workstation 52 includes a memory and a processor, with appropriate operating software stored in the memory, and user interface capabilities. The workstation 52 may provide multiple functions, optionally including: (1) modeling the endocardial anatomy in three dimensions (3D) and rendering the model, or anatomical map 54, for display on a display screen 56; (2) displaying on the display screen 56 activation sequences (or other data) compiled from recorded electrograms 44 with representative visual indicia or images superimposed on the rendered anatomical map 54; (3) displaying the real-time position and orientation of one or more catheters within the heart 24; and (4) displaying on the display screen 56 sites of interest, such as where ablation energy has been applied. A commercially available product embodying elements of the system 20 is the CARTO® 3 System, available from Biosense Webster, Inc., 31A Technology Drive, Irvine, CA 92618.

[0021] In the example of the present disclosure, workstation 52 processes the electrogram signals output by catheter 26 to find each annotation point corresponding to a local activation time and highlights the annotation point on display screen 56 by increasing the intensity of the trace within a time window that includes the local activation time. This display mode is further described below with reference to FIG. 3.

[0022] Display of local excitation time 2 is a plot that schematically illustrates the identification of an annotation point 100 in an exemplary electrophysiological signal 102, according to one example of the present disclosure. View 104 shows the electrophysiological signal 102 in a window 106. For clarity, view 104 is stretched along the time axis (horizontal axis) into view 108. A processor within workstation 52 (FIG. 1) calculates the location of annotation point 100 on signal 102 as a position between a positive peak 110 and a negative peak 112, where the slope 114 (time derivative) of the signal reaches an extreme negative value. This position corresponds to an inflection point in electrophysiological signal 102.

[0023] For more complex electrophysiological signals, the processor may use alternative algorithms to calculate the location of each of those annotation points.

[0024] 3 is a schematic diagram of a portion of the display screen 56 (FIG. 1) showing a highlighted segment of a recorded electrogram 44, according to one example of the present disclosure. The electrogram 44 is represented by a corresponding trace on the display screen 56 and labeled along the left edge of the display by alphanumeric labels A1-A8, B1-B8, C1-C8, D1-D8, E1-E8, and F1-F8. A window of interest (WOI) 200 encompassing the local activation time of the electrogram 44 is marked on the electrogram 44 by two vertical lines 202 and 204. The WOI 200 may be selected by an operator (e.g., physician 22) of the electrophysiology system or automatically selected by the system.

[0025] The processor of workstation 52 calculates the location of each annotation point corresponding to the local activation time in electrograms A1-A8, B1-B8, and D1-D8. The processor increases the intensity of electrogram segments within a time window of specified duration that includes the identified local activation time relative to the portion of the trace outside this time window. By way of example, such a bright segment is shown within box 206 around electrogram A3, while the remainder of the trace within WOI 200 is darkened. The portion of the trace outside WOI 200 may be dimmed or displayed at full intensity. Some of the other electrograms exhibit more complex signal forms, and the location of each annotation point has been calculated by the processor.

[0026] The time width of each bright segment around the annotation point is typically about 10-100 ms. In the example shown in Figure 3, the time window that is brightened in each trace has a duration of 15 ms. The LAT in each trace and the variation in LAT between traces can be easily visualized without overlaying an icon representing the local excitation time on the trace.

[0027] It will be understood that the above-described embodiments are given by way of example, and that the present disclosure is not limited to what is particularly shown and described hereinabove. Rather, the scope of the present disclosure includes both combinations and subcombinations of the various features described hereinabove, as well as variations and modifications thereof not disclosed in the prior art that would occur to one skilled in the art upon reading the foregoing description.

[0028] [Embodiment] (1) A method for electrophysiological measurements, comprising: obtaining signals indicative of cardiac electrical activity from electrodes in contact with body tissue of a living patient; processing the signal to identify local activation times in one or more of the electrodes; displaying on a display screen a trace representing the signal as a function of time, and increasing the intensity of segments of the trace within a time window of specified duration that includes the identified local excitation time relative to portions of the trace outside the time window. (2) The method of embodiment 1, wherein acquiring the signal includes receiving an intracardiac electrogram signal acquired within the heart of the living patient. (3) The method of embodiment 1, wherein acquiring the signal includes receiving an electrocardiogram signal acquired from a body surface of the living patient. (4) The method of embodiment 1, wherein the specified duration is 10 ms to 100 ms. (5) The method of embodiment 1, wherein displaying the trace includes presenting the trace on the display screen without overlaying an icon representing the local excitation time on the trace.

[0029] (6) A medical device, A display screen; a processor, the processor comprising: obtaining signals indicative of cardiac electrical activity from electrodes in contact with the body tissue of a living patient; processing the signals to identify local activation times in one or more of the electrodes; a medical device configured to display a trace representing the signal as a function of time on a display screen and to increase the intensity of segments of the trace within a time window of specified duration that includes the identified local excitation time relative to portions of the trace outside the time window. (7) The device of embodiment 6, wherein the signal comprises an intracardiac electrogram signal acquired within the heart of the living patient. (8) The device of embodiment 6, wherein the signal includes an electrocardiogram signal obtained from a body surface of the living patient. (9) The device described in embodiment 6, wherein the specified duration is 10 ms to 100 ms. (10) The device of embodiment 6, wherein the processor is configured to present the trace on the display screen without overlaying an icon representing the local excitation time on the trace.

[0030] (11) A computer-readable medium containing instructions for electrophysiological measurements, the instructions, when executed by a processor, causing the processor to: acquiring signals indicative of cardiac electrical activity from electrodes in contact with bodily tissue of a living patient; processing the signal to identify local activation times in one or more of the electrodes; displaying a trace representing the signal as a function of time on a display screen and increasing the intensity of segments of the trace within a time window of specified duration that includes the identified local excitation time relative to portions of the trace outside the time window. (12) The computer-readable medium of claim 11, wherein the instructions for acquiring the signals include instructions for receiving intracardiac electrogram signals acquired within the heart of the living patient. (13) The computer-readable medium of claim 11, wherein the instructions for acquiring the signals include instructions for receiving electrocardiogram signals acquired from a body surface of the living patient. (14) The computer-readable medium of embodiment 11, wherein the instruction for the specified duration sets a range of 10 ms to 100 ms. (15) The computer-readable medium of claim 11, wherein the instructions for displaying the trace include instructions for presenting the trace on the display screen without overlaying an icon representing the local excitation time on the trace.

Claims

1. A medical device comprising: A display screen; a processor, the processor comprising: obtaining signals indicative of cardiac electrical activity from electrodes in contact with the body tissue of a living patient; processing the signals to identify local activation times at one or more of the electrodes; a medical device configured to display a trace representing the signal as a function of time on a display screen and to increase the intensity of segments of the trace within a time window of specified duration that includes the identified local excitation time relative to portions of the trace outside the time window.

2. The apparatus of claim 1 , wherein the signal comprises an intracardiac electrogram signal acquired within the living patient's heart.

3. The apparatus of claim 1 , wherein the signal comprises an electrocardiogram signal obtained from a body surface of the living patient.

4. The apparatus of claim 1 , wherein the specified duration is between 10 ms and 100 ms.

5. 10. The apparatus of claim 1, wherein the processor is configured to present the trace on the display screen without overlaying an icon representing the local activation time on the trace.

6. 1. A computer-readable medium containing instructions for electrophysiological measurements, the instructions, when executed by a processor, causing the processor to: acquiring signals indicative of cardiac electrical activity from electrodes in contact with bodily tissue of a living patient; processing the signal to identify local activation times at one or more of the electrodes; displaying a trace representing the signal as a function of time on a display screen and increasing the intensity of segments of the trace within a time window of specified duration that includes the identified local excitation time relative to portions of the trace outside the time window.

7. 7. The computer-readable medium of claim 6, wherein the instructions for acquiring the signals include instructions for receiving intracardiac electrogram signals acquired within the living patient's heart.

8. The computer-readable medium of claim 6 , wherein the instructions for acquiring the signals include instructions for receiving electrocardiogram signals acquired from a body surface of the living patient.

9. 7. The computer-readable medium of claim 6, wherein the instruction for the specified duration sets a range from 10 ms to 100 ms.

10. 7. The computer-readable medium of claim 6, wherein the instructions for displaying the trace include instructions for presenting the trace on the display screen without overlaying an icon representing the local excitation time over the trace.

11. 1. A method for electrophysiological measurements, comprising: obtaining signals indicative of cardiac electrical activity from electrodes in contact with body tissue of a living patient; processing the signal to identify local activation times in one or more of the electrodes; displaying on a display screen a trace representing the signal as a function of time, and increasing the intensity of segments of the trace within a time window of specified duration that includes the identified local excitation time relative to portions of the trace outside the time window.

12. 12. The method of claim 11, wherein acquiring the signal comprises receiving an intracardiac electrogram signal acquired within the living patient's heart.

13. The method of claim 11 , wherein acquiring the signal comprises receiving an electrocardiogram signal acquired from a body surface of the living patient.

14. The method of claim 11, wherein the specified duration is between 10 ms and 100 ms.

15. 12. The method of claim 11, wherein displaying the trace comprises presenting the trace on the display screen without overlaying an icon representing the local activation time on the trace.

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