Method and system for removing pacing artifacts from subcutaneous electrocardiograms

• US 20050149134A1
• Filed: 12/24/2003
• Published: 07/07/2005
• Est. Priority Date: 12/24/2003
• Status: Active Grant

• Current Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Original Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Inventors: McCabe, Aaron, Yonce, David J.
• Granted Patent: US 7,277,754 B2
• Time in Patent Office: Days
• US Class Current: 607/9
• CPC Class Codes: A61N 1/3704 Circuits specially adapted therefor, e.g. for sensitivity control
• CPC Class Codes: Y10S 128/923 by comparison of patient data to other data

Abstract

An implantable cardiac rhythm management device is configured to remove pacing artifacts from recorded electrograms by a subtraction method. A template waveform representing a recorded pace without accompanying cardiac electrical activity is generated. Such a pacing pulse template is then aligned with the instant at which a pace is delivered and subtracted from the recorded electrogram in order to remove the pacing artifact.

Claims

1. A cardiac rhythm management device, comprising:

one or more sensing channels for sensing intrinsic cardiac activity;

a pacing channel for pacing a cardiac chamber;

a controller for controlling the delivery of pacing pulses in accordance with a programmed mode and recording electrograms from a sensing channel;

wherein the controller is programmed to remove the pacing artifact from an electrogram recorded during a paced cardiac cycle by subtracting a pacing pulse template from the recorded electrogram.

2. The device of claim 1 wherein the controller is programmed to align the pacing pulse template with the instant at which the pace is delivered during the paced cardiac cycle prior to subtracting the pacing pulse template from the recorded electrogram.

3. The device of claim 1 wherein the controller is programmed to insert a marker in the recorded electrogram after subtraction of the pacing pulse template indicating the pace delivered during the paced cardiac cycle.

4. The device of claim 1 wherein the controller is programmed to subtract samples of the pacing pulse template from corresponding samples of the recorded electrogram. 1

5. The device of claim 1 wherein the controller is programmed to subtract a sample of the pacing pulse template from a corresponding sample of the recorded electrogram as each sample of the recorded electrogram is acquired.

6. The device of claim 5 wherein the controller is programmed to wirelessly transmit a recorded electrogram from which pacing artifacts are removed in near real time.

7. The device of claim 1 wherein the controller is programmed to lower the gain of a sensing amplifier for recording an electrogram when a pace is delivered.

8. The device of claim 1 wherein the controller is programmed to remove the pacing artifact due to an atrial pace from an electrogram recorded during a cardiac cycle in which an atrial pace is delivered.

9. The device of claim 1 wherein the controller is programmed to remove the pacing artifact due to a ventricular pace from an electrogram recorded during a cardiac cycle in which a ventricular pace is delivered.

10. The device of claim 1 wherein the controller is programmed to generate the pacing pulse template by recording an electrogram when a pace is delivered to a cardiac chamber while the chamber is refractory.

21. The device of claim 1 further comprising a sensing channel incorporating a subcutaneous electrode for generating a subcutaneous ECG signal and wherein the controller is programmed to remove pacing artifacts from a recorded subcutaneous ECG signal.

11. A method for operating a cardiac rhythm management device, comprising:

sensing intrinsic cardiac activity via one or more sensing channels;

delivering pacing pulses to a cardiac chamber in accordance with a programmed mode;

recording an electrogram from a sensing channel;

removing pacing artifacts from the electrogram by subtracting a pacing pulse template from the recorded electrogram during each paced cardiac cycle.

12. The method of claim 11 further comprising aligning the pacing pulse template with the instant at which the pace is delivered during the paced cardiac cycle prior to subtracting the pacing pulse template from the recorded electrogram.

13. The method of claim 11 further comprising inserting a marker in the recorded electrogram after subtraction of the pacing pulse template indicating the pace delivered during the paced cardiac cycle.

14. The method of claim 11 further comprising subtracting samples of the pacing pulse template from corresponding samples of the recorded electrogram.

15. The method of claim 11 further comprising subtracting a sample of the pacing pulse template from a corresponding sample of the recorded electrogram as each sample of the recorded electrogram is acquired.

16. The method of claim 15 further comprising wirelessly transmitting a recorded electrogram from which pacing artifacts are removed in near real time.

17. The method of claim 11 further comprising lowering the gain of a sensing amplifier for recording an electrogram when a pace is delivered.

18. The method of claim 11 further comprising removing the pacing artifact due to an atrial pace from an electrogram recorded during a cardiac cycle in which an atrial pace is delivered.

19. The method of claim 11 further comprising removing the pacing artifact due to a ventricular pace from an electrogram recorded during a cardiac cycle in which a ventricular pace is delivered.

20. The method of claim 11 further comprising generating the pacing pulse template by recording an electrogram when a pace is delivered to a cardiac chamber while the chamber is refractory.

22. The method of claim 11 further comprising recording a subcutaneous ECG signal from a sensing channel incorporating a subcutaneous electrode and remove pacing artifacts from the recorded subcutaneous ECG signal.

23. A system for removing pacing artifacts from electrograms, comprising:

an implantable device having a sensing channel for sensing intrinsic cardiac activity and a pacing channel for delivering pacing pulses to a cardiac chamber in accordance with a programmed mode;

an external device in communication with the implantable device;

wherein the implantable device is programmed to record an electrogram from a sensing channel and transmit the electrogram to the external device; and

,

wherein the external device is programmed to remove pacing artifacts from the electrogram by subtracting a pacing pulse template from the recorded electrogram during each paced cardiac cycle.

24. The system of claim 23 wherein the pacing pulse template is generated by the implantable device and transmitted to the external device.