Implantable medical device with ventricular pacing protocol

• US 20060167506A1
• Filed: 01/21/2005
• Published: 07/27/2006
• Est. Priority Date: 01/21/2005
• Status: Active Grant

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Boute, Willem, Rouw, Mattias, Van Dam, Peter M., Stoop, Gustaaf A.P.
• Granted Patent: US 7,542,799 B2
• Time in Patent Office: Days
• US Class Current: 607/9
• CPC Class Codes: A61N 1/3622 comprising two or more electrodes co-operating with different heart regions
• CPC Class Codes: A61N 1/368 comprising more than one electrode co-operating with different heart regions A61N1/3622, A61N1/3627 take precedence
• CPC Class Codes: A61N 1/3688 configured for switching the pacing mode, e.g. from AAI to DDD

Abstract

An implantable medical device operates to promote intrinsic ventricular depolarization according to a pacing protocol. The medical device determines a course of action based upon the presence or absence of sensed ventricular activity. The device further determines whether that activity is properly conducted or the result of a PVC or nodal rhythm.

Claims

1. A method of operating an implantable medical device (IMD) that provides cardiac pacing and sensing, the method comprising:

operating the IMD in an atrial based pacing mode with a ventricular pacing protocol (VPP);

sensing for intrinsic ventricular activity;

determining the nature of the sensed ventricular activity;

operating normally in the atrial based pacing mode if the sensed ventricular activity is determined to be a properly conducted ventricular beat;

initiating a first response under the VPP if the sensed ventricular activity is determined to be a nodal rhythm; and

initiating a second response under the VPP if the sensed ventricular activity is determined to be a premature ventricular contraction (PVC).

2. The method of claim 1, wherein the VPP operates in an atrial based pacing mode and changes to a dual chamber pacing mode for one cardiac cycle immediately following a given cardiac cycle devoid of sensed intrinsic ventricular activity, with a return to the atrial based pacing mode immediately subsequent to the one cardiac cycle.

3. The method of claim 2, wherein the VPP further includes an aggressiveness level indicating a maximum number of cardiac cycles devoid of sensed intrinsic ventricular activity in a given interval tolerated by the VPP.

4. The method of claim 1, further comprising:

conducting a conduction check prior to operating in the atrial based pacing mode to determine in intrinsic conduction is present;

sensing for intrinsic ventricular activity;

analyzing any ventricular activity sensed;

failing the conduction check and operating in a dual chamber pacing mode if no ventricular activity is sensed;

operating in an atrial based pacing mode on an ongoing basis if the sensed ventricular activity is a properly conducted ventricular beat; and

failing the conduction check and operating in the dual chamber pacing mode if the sensed ventricular activity is an improper event.

5. The method of claim 4, wherein the improper event is a PVC.

6. The method of claim 4, wherein the improper event is a nodal rhythm.

7. The method of claim 1, wherein the first response includes:

operating in a dual chamber mode;

initiating a pacing therapy to terminate the nodal rhythm for a first duration;

performing a conduction check subsequent to the pacing therapy; and

operating in the atrial based pacing mode if the conduction check is successful.

8. The method of claim 7, further comprising:

initiating the pacing therapy for a second duration, wherein the second duration is longer than the first duration, if the conduction check fails;

performing a second conduction check subsequent to the pacing therapy of the second duration; and

operating in the atrial based pacing mode if the second conduction check is successful.

9. The method of claim 8, further comprising discontinuing the VPP if the second conduction check fails.

10. The method of claim 1, wherein the second response includes:

determining if the PVC is a first occurrence within a predetermined window; and

considering the first occurrence of a PVC within the window as a properly conducted ventricular event.

11. The method of claim 1, wherein the second response includes:

determining if the PVC is a first occurrence within a predetermined window; and

modifying an aggressiveness level of the VPP if the PVC is the first occurrence within the window.

12. The method of claim 1, wherein the second response includes:

determining if the PVC is a first occurrence within a predetermined window; and

operating under the VPP as if no ventricular activity were sensed if the PVC is the first occurrence.

13. The method of claim 1, wherein the second response further includes:

determining if the PVC was preceded by an earlier PVC in an immediately prior cardiac cycle; and

changing the VPP to a least aggressive setting if the PVC was preceded by an earlier PVC in the immediately prior cardiac cycle.

14. The method of claim 13, further comprising:

determining an AV interval as defined by an atrial event and terminated by the PVC; and

returning to a more aggressive VPP setting after one cardiac cycle in the least aggressive VPP setting if the AV interval is less than a predetermined duration.

15. The method of claim 1, wherein the second response further includes:

determining a PVC occurrence rate for a predetermined time period; and

operating the IMD in a less aggressive VPP setting if the total PVC occurrence rate exceeds a threshold.

16. The method of claim 15, further comprising:

determining if the PVC occurrence rate has exceeded the threshold for multiple consecutive predetermined time periods; and

disabling the VPP if the PVC occurrence rate has exceeded the threshold for multiple consecutive predetermined time periods.

17. The method of claim 15, wherein disabling the VPP will only occur if the VPP is currently in a least aggressive setting.

18. An implantable medical device (IMD) comprising:

means for cardiac sensing and pacing;

means for distinguishing regular ventricular events from improper ventricular events; and

means for controlling the means for cardiac sensing and pacing according to a Ventricular Pacing Protocol (VPP) that respond in a first manner to the regular ventricular event and in a second manner for the improper ventricular event.

19. The IMD of claim 18, wherein improper ventricular events include premature ventricular contractions (PVC) or nodal rhythms.

20. The IMD of claim 19, wherein the second manner further includes a PVC response and a nodal rhythm response.