Artifact cancellation to suppress far-field activation during electrophysiology mapping

• US 9,439,578 B2
• Filed: 12/20/2013
• Issued: 09/13/2016
• Est. Priority Date: 12/27/2012
• Status: Active Grant

• Current Assignee: Boston Scientific Scimed, Inc. (Boston Scientific Corporation)
• Original Assignee: Boston Scientific Scimed, Inc. (Boston Scientific Corporation)
• Inventors: Thakur, Pramodsingh H., Arcot-Krishnamurthy, Shantha, Maskara, Barun, Saha, Sunipa, Shuros, Allan C., Shome, Shibaji
• Primary Examiner(s): EVANISKO, GEORGE ROBERT
• Application Number:
  US14/136,378
• Publication Number:
  US 20140187991A1
• Time in Patent Office: 998 Days
• Field of Search: 600509-510
• US Class Current: 1/1
• CPC Class Codes: A61B 18/1206 Generators therefor
• CPC Class Codes: A61B 18/1492 having a flexible, catheter-like structure, e.g. for heart ablation A61B18/1477 takes precedence
• CPC Class Codes: A61B 2018/00351 Heart
• CPC Class Codes: A61B 2018/00577 Ablation
• CPC Class Codes: A61B 2018/00595 Cauterization
• CPC Class Codes: A61B 2018/00642 with feedback, i.e. closed loop control
• CPC Class Codes: A61B 2018/00839 Bioelectrical parameters, e.g. ECG, EEG
• CPC Class Codes: A61B 5/287 Holders for multiple electrodes, e.g. electrode catheters for electrophysiological study [EPS]
• CPC Class Codes: A61B 5/316 Modalities, i.e. specific diagnostic methods
• CPC Class Codes: A61B 5/349 Detecting specific parameters of the electrocardiograph cycle
• CPC Class Codes: A61B 5/352 Detecting R peaks, e.g. for synchronising diagnostic apparatus; Estimating R-R interval
• CPC Class Codes: A61B 5/6858 with a distal basket, e.g. expandable basket
• CPC Class Codes: A61B 5/7203 for noise prevention, reduction or removal
• CPC Class Codes: A61B 5/725 using specific filters therefor, e.g. Kalman or adaptive filters A61B5/316 take precedence
• CPC Class Codes: A61B 5/7282 Event detection, e.g. detecting unique waveforms indicative of a medical condition A61B5/4094, A61B5/4818, A61B5/349, A61B5/0823 take precedence
• CPC Class Codes: A61N 1/056 Transvascular endocardial electrode systems
• CPC Class Codes: A61N 1/3702 Physiological parameters A61N1/365 takes precedence; evoked response A61N1/371

Abstract

A method for mapping a cardiac chamber includes sensing activation signals of intrinsic physiological activity with a plurality of electrodes disposed in or near the cardiac chamber, the activation signals including a near-field activation signal component and a far-field activation signal component, isolating R-wave events in the activation signals, generating a far-field activation template representative of the far-field activation signal component based on the R-wave events, and filtering the far-field activation template from the activation signals to identify the near-field activation signal components in the activation signals.

Claims

1. A method for mapping a cardiac chamber, the method comprising:

sensing activation signals of intrinsic physiological activity with a plurality of electrodes disposed in or near the cardiac chamber, the activation signals including a near-field activation signal component and a far-field activation signal component, wherein the plurality of electrodes are disposed on a catheter;

isolating far-field events in the activation signals;

segmenting the activation signals sensed by each electrode;

generating a far-field activation template representative of the far-field activation signal component by averaging the far-field events in the segmented activation signals from each electrode;

comparing amplitudes among a set of consecutive far-field segmented activation signals corresponding to an electrode of the plurality of electrodes;

determining that the consecutive far-field segmented activation signals have inconsistent amplitudes;

blanking the electrode in the plurality of electrodes based on determining that the consecutive far-field segmented activation signals have inconsistent amplitudes; and

subtracting the far-field activation template from the activation signals at the isolated far-field events to identify the near-field activation signal components in the activation signals.

2. The method according to claim 1, wherein the step of segmenting the activation signals sensed by each electrode comprises:

obtaining a reference timing for far-field events; and

segmenting the activation signals sensed by each electrode around far-field events according to the obtained reference timing.

3. The method according to claim 2, wherein the far-field event corresponds to a ventricular activation signal and the reference timing corresponds to at least one of a Q-wave and an R-wave event in an electrogram.

4. The method according to claim 1, wherein, prior to subtracting the far-field activation template, the step of filtering the far-field activation template from the activation signals further comprises:

fitting an amplitude of the far-field template to correspond to an amplitude of each isolated far-field event.

5. The method according to claim 1, wherein the step of filtering the far-field activation template from the activation signals comprises:

identifying a time period during which the far-field activation signal component is present; and

filtering the far-field activation template only during the time period.

6. The method according to claim 1, and further comprising:

averaging the far-field activation template with far-field activation signal components during a predetermined number of subsequent far-field events to update the far-field activation template.

7. The method according to claim 1, further comprising:

selecting a subset of the plurality of electrodes based on the location on the catheter of the subset of the plurality of the electrodes;

wherein the step of isolating far-field events in the activation signals comprises isolating far-field events in the activation signals sensed by the subset of the plurality of electrodes.

8. The method according to claim 1, wherein the catheter comprises a mapping catheter.

9. A method for reconstructing electrical activity propagation along an electrode array within a cardiac chamber, the method comprising:

sensing activation signals of intrinsic physiological activity with a plurality of electrodes disposed in or near the cardiac chamber, the activation signals including a near-field activation signal component and a far-field activation signal component, wherein the plurality of electrodes are disposed on a catheter;

isolating far-field events in the activation signals;

segmenting the activation signals sensed by each electrode;

generating a far-field activation template representative of the far-field activation signal component by averaging the far-field events in the segmented activation signals from each electrode;

subtracting the far-field activation template from the activation signals at the isolated far-field events to identify the near-field activation signal components in the activation signals;

comparing amplitudes among a set of consecutive far-field segmented activation signals corresponding to an electrode of the plurality of electrodes;

determining that the consecutive far-field segmented activation signals have inconsistent amplitudes;

blanking the electrode in the plurality of electrodes based on determining that the consecutive far-field segmented activation signals have inconsistent amplitudes; and

mapping the identified near-field activation signal components.

10. The method according to claim 9, wherein the step of segmenting the activation signals sensed by each electrode comprises:

obtaining a reference timing for far-field events; and

segmenting the activation signals sensed by each electrode around far-field events according to the obtained reference timing in the activation signals.

11. The method according to claim 10, wherein the far-field event corresponds to a ventricular activation signal and the reference timing to at least one of a Q-wave and an R-wave event in an electrogram.

12. The method according to claim 9, wherein, prior to subtracting the far-field activation template, the step of filtering the far-field activation template from the activation signals further comprises:

fitting an amplitude of the far-field template to correspond to an amplitude of each isolated far-field event.

13. The method according to claim 9, wherein the step of filtering the far-field activation template from the activation signals comprises:

identifying a time period during which the far-field activation signal component is present; and

filtering the far-field activation template only during the time period.

14. The method according to claim 9, and further comprising:

averaging the far-field activation template with far-field activation signal components during a predetermined number of subsequent R-wave events to update the far-field activation template.

15. A catheter system comprising:

a catheter;

a plurality of mapping electrodes disposed on the catheter and configured to sense activation signals of intrinsic physiological activity disposed in or near the cardiac chamber, the activation signals including a near-field activation signal component and a far-field activation signal component; and

a signal processing system associated with the plurality of mapping electrodes, the signal processing system configured to isolate far-field events in the activations, segment the activation signals sensed by each electrode and average the isolated far-field events in the segmented activation signals from each electrode to generate a far-field activation template representative of the far-field activation signal component, the processing system further configured to subtract the far-field activation template from the activation signals at the isolated far-field events to identify the near-field activation signal components in the activation signals, to compare amplitudes among a set of consecutive far-field segmented activation signals corresponding to an electrode of the plurality of electrodes, to determine that the consecutive far-field segmented activation signals have inconsistent amplitudes, to blank the electrode in the plurality of electrodes based on determining that the consecutive far-field segmented activation signals have inconsistent amplitudes, and to map the identified near-field activation signal component.

16. The catheter system according to claim 15, wherein when the processing device segments the activation signals sensed by each electrode, the processing system is configured to obtain a reference timing for far-field events and segment the activation signals sensed by each electrode around far-field events according to the obtained reference timing to isolate the R-wave event in the activation signal.