Artifact cancellation to suppress far-field activation during electrophysiology mapping

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.