Multiple channel sequential cardiac pacing method

• US 6,122,545 A
• Filed: 04/28/1998
• Issued: 09/19/2000
• Est. Priority Date: 04/28/1998
• Status: Expired due to Term

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Struble, Chester L., Nijsten, Albert-Jan, De Roos, Cobus
• Primary Examiner(s): Kamm, William E.
• Application Number:
  US09/067,729
• Time in Patent Office: 875 Days
• Field of Search: 607/4, 607/9, 607/14
• US Class Current: 607/9
• CPC Class Codes: A61N 1/3627 for treating a mechanical deficiency of the heart, e.g. congestive heart failure or cardiomyopathy
• CPC Class Codes: A61N 1/368 comprising more than one electrode co-operating with different heart regions A61N1/3622, A61N1/3627 take precedence

Abstract

Multi-chamber cardiac pacing systems for providing synchronous pacing to at least the two upper heart chambers or the two lower heart chambers or to three heart chambers or to all four heart chambers employing programmable conduction delay window (CDW) times timed out from paced and sensed events occurring in each heart chamber are disclosed. The synchronous pacing of one of the right and left heart chambers is provided on demand following expiration of programmable pace and sense CDWs that are started by both a paced event and a sensed event first occurring in the other of the right and left heart chambers. The delivery of the pacing pulse is inhibited by a sensed event detected in the other of the right and left heart chambers before the expiration of the corresponding CDW. In a four channel atrial and ventricular pacing system, the right and left atrial chambers are sensed and paced as necessary upon at the end of a V-A escape interval and right and left AV delays are commenced for sensing ventricular depolarizations in the right and left ventricles. The four channel system is programmable to pace and sense in three selected heart chambers.

Claims

1. A pacing system for improving the hemodynamic efficiency of a sick heart suffering from conduction delays in conducting spontaneous or evoked depolarizations originating in one of the right or left heart chamber to the other of the left or right heart chamber comprising:

right heart lead means for locating first and second right heart chamber pace/sense electrodes in relation with the right heart chamber;

left heart lead means for locating first and second left heart chamber pace/sense electrodes in relation with the left heart chamber;

right heart chamber depolarization sensing means coupled with said right heart chamber lead means for sensing spontaneous cardiac depolarizations originating in the right heart chamber and conducted cardiac depolarizations originating in the left heart chamber from a spontaneous cardiac depolarization or delivery of a left heart pacing pulse to the left heart chamber and for providing a right heart chamber sensed event signal in response to either a sensed spontaneous or conducted cardiac depolarization;

left heart chamber depolarization sensing means coupled with said left heart chamber lead means for sensing spontaneous cardiac depolarizations originating in the left heart chamber and conducted cardiac depolarizations originating in the right heart chamber from a spontaneous cardiac depolarization or delivery of a right heart pacing pulse to the right heart chamber a paced event and for providing a left heart chamber sensed event signal in response to either a sensed spontaneous or conducted cardiac depolarization;

escape interval timing means for timing an escape interval establishing a pacing rate and providing an escape interval pace trigger signal at the time out of the escape interval, the escape interval timing means further comprising reset means for restarting the timing of the escape interval in response to one of the right or left heart chamber sensed event signals;

right heart pacing pulse output means coupled with said right heart chamber lead means and selectively responsive to an applied pace trigger signal for generating and delivering a right heart pacing pulse to said right heart chamber lead means to evoke a right heart chamber depolarization;

left heart pacing pulse output means coupled with said left heart chamber lead means and selectively responsive to an applied pace trigger signal for generating and delivering a left heart pacing pulse to said left heart chamber lead means to evoke a left heart chamber depolarization;

means for applying said escape interval pace trigger signal to one of said right heart pacing pulse output means or said left heart pacing pulse output means;

left heart chamber conduction delay window timing means coupled with said escape interval timing means and said right heart chamber depolarization sensing means for timing a left heart chamber conduction delay window from a right heart chamber sensed event signal and selectively from an escape interval pace trigger signal and for providing a left heart chamber pace trigger signal at the expiration of the left heart chamber conduction delay window time, said left heart chamber conduction delay window timing means further coupled with said left heart chamber depolarization sensing means and comprising left heart chamber window terminating means for terminating the timing out of the left heart chamber conduction delay window in response to a left heart chamber sensed event signal;

means for applying said left heart chamber pace trigger signal to said left heart pacing pulse output means as a pace trigger signal for triggering the generation and delivery of a left heart pacing pulse to said left heart chamber lead means;

right heart chamber conduction delay window timing means coupled with said escape interval timing means and said left heart chamber depolarization sensing means for timing a right heart chamber conduction delay window from a left heart chamber sensed event signal and selectively from an escape interval pace trigger signal and for providing a right heart chamber pace trigger signal at the expiration of the right heart chamber conduction delay window time, said right heart chamber conduction delay window timing means further coupled with said right heart chamber depolarization sensing means and comprising right heart chamber window terminating means for terminating the timing out of the right heart chamber conduction delay window in response to a right heart chamber sensed event signal; and

means for applying said right heart chamber pace trigger signal to said right heart pacing pulse output means as a pace trigger signal for triggering the generation and delivery of a right heart pacing pulse to said right heart chamber lead means;

whereby an excessive conduction delay between a spontaneous or evoked depolarization in the right heart chamber and the conducted depolarization wave in the left heart chamber or an excessive conduction delay between a spontaneous or evoked depolarization in the left heart chamber and the conducted depolarization wave in the right heart chamber is corrected by generation and delivery of a pacing pulse to the left or right heart chamber, respectively at the timing out of the corresponding conduction delay window.

2. The pacing system of claim 1, further comprising:

means for selecting one of the right or left heart chamber sensed event signals for use by said reset means to restart the escape interval.

3. The pacing system of claim 2, further comprising:

means for selectively disabling said right heart chamber conduction delay window timing means to configure said pacing system to only provide said left heart chamber pace trigger signal for treating an abnormal conduction delay from the right heart chamber to the left heart chamber; and

means for selectively disabling said left heart chamber conduction delay window timing means to configure said pacing system to only provide said right heart chamber pace trigger signal for treating an abnormal conduction delay from the left heart chamber to the right heart chamber.

4. The pacing system of claim 3, further comprising:

right heart chamber blanking means coupled with said right heart chamber depolarization sensing means for preventing the sensing of spontaneous and evoked cardiac depolarizations in the right heart chamber and provision of a right heart chamber sensed event signal for the duration of a right heart chamber blanking period;

left heart chamber blanking means coupled with said left heart chamber depolarization sensing means for preventing the sensing of spontaneous and evoked cardiac depolarizations in the left heart chamber and provision of a left heart chamber sensed event signal for the duration of a left heart chamber blanking period; and

means for triggering operation of said right and left heart chamber blanking means in response to the generation of a right heart pacing pulse and a left heart pacing pulse.

5. The pacing system of claim 1, further comprising:

means for applying one of the right or left heart chamber sensed event signals to said reset means to restart the escape interval timer; and

means for applying said escape interval pace trigger signal to one of the right or left heart chamber pacing pulse output means to generate a right or left heart chamber pacing pulse upon the time out of the escape interval.

6. The pacing system of claim 5, further comprising:

right heart chamber blanking means coupled with said right heart chamber depolarization sensing means for preventing the sensing of spontaneous and evoked cardiac depolarizations in the right heart chamber and provision of a right heart chamber sensed event signal for the duration of a right heart chamber blanking period;

left heart chamber blanking means coupled with said left heart chamber depolarization sensing means for preventing the sensing of spontaneous and evoked cardiac depolarizations in the left heart chamber and provision of a left heart chamber sensed event signal for the duration of a left heart chamber blanking period; and

means for triggering operation of said right and left heart chamber blanking means in response to the generation of a right heart pacing pulse and a left heart pacing pulse.

7. The pacing system of claim 1, further comprising:

right heart chamber blanking means coupled with said right heart chamber depolarization sensing means for preventing the sensing of spontaneous and evoked cardiac depolarizations in the right heart chamber and provision of a right heart chamber sensed event signal for the duration of a right heart chamber blanking period;

left heart chamber blanking means coupled with said left heart chamber depolarization sensing means for preventing the sensing of spontaneous and evoked cardiac depolarizations in the left heart chamber and provision of a left heart chamber sensed event signal for the duration of a left heart chamber blanking period; and

means for triggering operation of said right and left heart chamber blanking means in response to the generation of a right heart pacing pulse and a left heart pacing pulse.

8. The pacing system of claim 1, further comprising:

means for programming said left heart chamber conduction delay window in a range of 0-100 msec; and

means for programming said right heart chamber conduction delay window in a range of 0-100 msec.

9. A pacing method for improving the hemodynamic efficiency of a sick heart suffering from conduction delays in conducting spontaneous or evoked depolarizations originating in one of the right or left heart chamber to the other of the left or right heart chamber comprising the steps of:

locating first and second right heart chamber pace/sense electrode in relation with the right heart chamber;

locating first and second left heart chamber pace/sense electrodes in relation with the left heart chamber;

sensing spontaneous and evoked cardiac depolarizations in the right heart chamber across said right heart chamber pace/sense electrodes and providing a right heart chamber sensed event signal;

sensing spontaneous and evoked cardiac depolarizations in the left heart chamber across said left heart chamber pace/sense electrodes and providing a left heart chamber sensed event signal;

timing an escape interval establishing a pacing rate and providing an escape interval pace trigger signal at the time out of the escape interval;

restarting the timing of the escape interval in response to one of the right or left heart chamber sensed event signals;

in response to the escape interval pace trigger signal, selectively triggering either right heart pacing pulse output means coupled with said right heart chamber pace/sense electrodes to generate and deliver a right heart pacing pulse to said right heart chamber pace/sense electrodes to evoke a right heart chamber depolarization or left heart pacing pulse output means coupled with said left heart chamber pace/sense electrodes to generate and deliver a left heart pacing pulse to said left heart chamber lead means to evoke a left heart chamber depolarization;

timing a left heart chamber conduction delay window from a right heart chamber sensed event signal or from generation of a right heart pacing pulse and providing a left heart chamber pace trigger signal at the expiration of the left heart chamber conduction delay window;

terminating the timing out of the left heart chamber conduction delay window in response to a left heart chamber sensed event signal;

applying said left heart chamber pace trigger signal to said left heart pacing pulse output means to trigger the generation and delivery of a left heart pacing pulse to said left heart chamber lead means;

timing a right heart chamber conduction delay window from a left heart chamber sensed event signal or from generation of a left heart pacing pulse and providing a right heart chamber pace trigger signal at the expiration of the right heart chamber conduction delay window;

terminating the timing out of the right heart chamber conduction delay window in response to a right heart chamber sensed event signal; and

applying said right heart chamber pace trigger signal to said right heart pacing pulse output means to trigger the generation and delivery of a right heart pacing pulse to said right heart chamber lead means;

whereby an excessive conduction delay between a spontaneous or evoked depolarization in one of the right or left heart chamber and the conducted depolarization wave in the other of the left or right heart chamber is corrected by generation and delivery of a pacing pulse at the timing out of the conduction delay window.

10. The pacing method of claim 9, further comprising the step of:

selecting one of the right or left heart chamber sensed event signals for use by said reset means.

11. The pacing method of claim 10, further comprising the steps of:

selectively disabling said right heart chamber conduction delay window timing means to configure said pacing system to only provide said left heart chamber pace trigger signal for treating an abnormal conduction delay from the right heart chamber to the left heart chamber; and

selectively disabling said left heart chamber conduction delay window timing means to configure said pacing system to only provide said right heart chamber pace trigger signal for treating an abnormal conduction delay from the left heart chamber to the right heart chamber.

12. The pacing method of claim 11, further comprising the steps of:

preventing the sensing of spontaneous and evoked cardiac depolarizations in the right heart chamber and the provision of a right heart chamber sensed event signal in response thereto for the duration of a right heart chamber blanking period in response to the generation of a right heart pacing pulse and a left heart pacing pulse; and

preventing the sensing of spontaneous and evoked cardiac depolarizations in the left heart chamber and the provision of a left heart chamber sensed event signal in response thereto for the duration of a left heart chamber blanking period in response to the generation of a right heart pacing pulse and a left heart pacing pulse.

13. The pacing method of claim 9, further comprising the steps of:

employing one of the right or left heart chamber sensed event signals to restart the timing of the escape interval; and

applying said escape interval pace trigger signal to one of the right or left heart chamber pacing pulse output means to generate a right or left heart chamber pacing pulse upon the time out of the escape interval.

14. The pacing method of claim 13, further comprising the steps of:

preventing the sensing of spontaneous and evoked cardiac depolarizations in the right heart chamber and the provision of a right heart chamber sensed event signal in response thereto for the duration of a right heart chamber blanking period in response to the generation of a right heart pacing pulse and a left heart pacing pulse; and

preventing the sensing of spontaneous and evoked cardiac depolarizations in the left heart chamber and the provision of a left heart chamber sensed event signal in response thereto for the duration of a left heart chamber blanking period in response to the generation of a right heart pacing pulse and a left heart pacing pulse.

15. The pacing method of claim 9, further comprising the steps of:

preventing the sensing of spontaneous and evoked cardiac depolarizations in the right heart chamber and the provision of a right heart chamber sensed event signal in response thereto for the duration of a right heart chamber blanking period in response to the generation of a right heart pacing pulse and a left heart pacing pulse; and

preventing the sensing of spontaneous and evoked cardiac depolarizations in the left heart chamber and the provision of a left heart chamber sensed event signal in response thereto for the duration of a left heart chamber blanking period in response to the generation of a right heart pacing pulse and a left heart pacing pulse.

16. The pacing method of claim 9, further comprising the steps of:

programming said left heart chamber conduction delay window in a range of 0-100 msec; and

programming said right heart chamber conduction delay window in a range of 0-100 msec.

17. A pacing method for improving the hemodynamic efficiency of a sick heart suffering from conduction delays in conducting spontaneous or evoked depolarizations originating in a right heart chamber to the corresponding left heart chamber comprising the steps of:

locating first and second right heart chamber pace/sense electrode in relation with the right heart chamber;

locating first and second left heart chamber pace/sense electrodes in relation with the left heart chamber;

sensing spontaneous and evoked cardiac depolarizations in the right heart chamber across said right heart chamber pace/sense electrodes and providing a right heart chamber sensed event signal;

sensing spontaneous and evoked cardiac depolarizations in the left heart chamber across said left heart chamber pace/sense electrodes and providing a left heart chamber sensed event signal;

timing an escape interval establishing a pacing rate and providing an escape interval pace trigger signal at the time out of the escape interval;

restarting the timing of the escape interval in response to the right heart chamber sensed event signals;

in response to the escape interval pace trigger signal, triggering the right heart pacing pulse output means coupled with said right heart chamber pace/sense electrodes to generate and deliver a right heart pacing pulse to said right heart chamber pace/sense electrodes to evoke a right heart chamber depolarization;

timing a left heart chamber conduction delay window from a right heart chamber sensed event signal or from generation of a right heart pacing pulse and providing a left heart chamber pace trigger signal at the expiration of the left heart chamber conduction delay window;

terminating the timing out of the left heart chamber conduction delay window in response to a left heart chamber sensed event signal; and

applying said left heart chamber pace trigger signal to said left heart pacing pulse output means to trigger the generation and delivery of a left heart pacing pulse to said left heart chamber lead means;

whereby an excessive conduction delay between a spontaneous or evoked depolarization in the right heart chamber and the conducted depolarization wave in the left heart chamber is corrected by generation and delivery of a pacing pulse at the timing out of the conduction delay window.

18. The pacing method of claim 17, further comprising the step of:

programming said left heart chamber conduction delay window in a range of 0-100 msec.

19. The pacing method of claim 17, further comprising the steps of:

preventing the sensing of spontaneous and evoked cardiac depolarizations in the right heart chamber and the provision of a right heart chamber sensed event signal in response thereto for the duration of a right heart chamber blanking period in response to the generation of a right heart pacing pulse and a left heart pacing pulse; and

preventing the sensing of spontaneous and evoked cardiac depolarizations in the left heart chamber and the provision of a left heart chamber sensed event signal in response thereto for the duration of a left heart chamber blanking period in response to the generation of a right heart pacing pulse and a left heart pacing pulse.

20. A pacing system for improving the hemodynamic efficiency of a sick heart suffering from conduction delays in conducting spontaneous or evoked depolarizations originating in a right heart chamber to the corresponding left heart chamber comprising:

right heart lead means for locating first and second right heart chamber pace/sense electrode in relation with the right heart chamber;

left heart lead means for locating first and second left heart chamber pace/sense electrodes in relation with the left heart chamber;

right heart sensing means for sensing spontaneous and evoked cardiac depolarizations in the right heart chamber across said right heart chamber pace/sense electrodes and providing a right heart chamber sensed event signal;

left heart sensing means for sensing spontaneous and evoked cardiac depolarizations in the left heart chamber across said left heart chamber pace/sense electrodes and providing a left heart chamber sensed event signal;

escape interval timing means for timing an escape interval establishing a pacing rate and providing an escape interval pace trigger signal at the time out of the escape interval;

reset means for restarting the timing of the escape interval in response to the right heart chamber sensed event signals;

right heart chamber pacing pulse output means coupled with said right heart chamber pace/sense electrodes responsive to the escape interval pace trigger signal for generating and delivering a right heart pacing pulse to said right heart chamber pace/sense electrodes to evoke a right heart chamber depolarization;

means for timing a left heart chamber conduction delay window from a right heart chamber sensed event signal or from generation of a right heart pacing pulse and providing a left heart chamber pace trigger signal at the expiration of the left heart chamber conduction delay window;

means for terminating the timing out of the left heart chamber conduction delay window in response to a left heart chamber sensed event signal; and

left heart chamber pacing pulse output means coupled with said left heart chamber pace/sense electrodes and responsive to said left heart chamber pace trigger signal for generating and delivering a left heart pacing pulse to said left heart chamber lead means;

whereby an excessive conduction delay between a spontaneous or evoked depolarization in the right heart chamber and the conducted depolarization wave in the left heart chamber is corrected by generation and delivery of a pacing pulse at the timing out of the conduction delay window.

21. The pacing system of claim 20, further comprising:

means for preventing the sensing of spontaneous and evoked cardiac depolarizations in the right heart chamber and the provision of a right heart chamber sensed event signal in response thereto for the duration of a right heart chamber blanking period in response to the generation of a right heart pacing pulse and a left heart pacing pulse; and

means for preventing the sensing of spontaneous and evoked cardiac depolarizations in the left heart chamber and the provision of a left heart chamber sensed event signal in response thereto for the duration of a left heart chamber blanking period in response to the generation of a right heart pacing pulse and a left heart pacing pulse.

22. The pacing system of claim 20, further comprising means for programming said left heart chamber conduction delay window in a range of 0-100 msec.

23. A four channel pacing system for improving the hemodynamic efficiency of a sick heart suffering from conduction delays in conducting spontaneous or evoked depolarizations originating in a right heart chamber to the corresponding left heart chamber comprising:

right atrial heart lead means for locating first and second right atrial pace/sense electrodes in relation with the right atrium;

right atrial sensing means for sensing spontaneous and evoked cardiac depolarizations in the right atrium across said right atrium pace/sense electrodes and providing a right atrial sensed event signal;

left atrial lead means for locating first and second left atrial pace/sense electrodes in relation with the left atrium;

left atrial sensing means for sensing spontaneous and evoked cardiac depolarizations in the left atrium across said left atrium pace/sense electrodes and providing a left atrial sensed event signal;

right ventricular heart lead means for locating first and second right ventricular pace/sense electrodes in relation with the right ventricle;

right ventricular sensing means for sensing spontaneous and evoked cardiac depolarizations in the right ventricle across said right ventricular pace/sense electrodes and providing a right ventricular sensed event signal;

means for timing a right heart AV delay from a right atrial sensed event signal or a right atrial pacing pulse and providing a ventricular pace trigger signal upon the time out of the right heart AV delay;

reset means for terminating the timing of the right heart AV delay in response to a right ventricular sensed event signal;

right ventricular pacing pulse output means coupled with said right ventricular pace/sense electrodes responsive to the time out of the right heart AV delay for generating and delivering a right ventricular pacing pulse to said right ventricular pace/sense electrodes to evoke a right ventricular depolarization;

escape interval timing means for timing an escape interval establishing a pacing rate upon the generation of a right ventricular pacing pulse or a right ventricular sensed event signal and providing an escape interval pace trigger signal at the time out of the escape interval;

right atrial pacing pulse output means coupled with said right atrial pace/sense electrodes responsive to the escape interval pace trigger signal for generating and delivering a right atrial pacing pulse to said right atrial pace/sense electrodes to evoke a right atrial depolarization;

means for timing a left atrial conduction delay window from a right atrial sensed event signal or from generation of a right atrial pacing pulse and providing a left atrial pace trigger signal at the expiration of the left atrial conduction delay window;

means for terminating the timing out of the left atrial conduction delay window in response to a left atrial sensed event signal; and

left atrial pacing pulse output means coupled with said left atrial pace/sense electrodes and responsive to said left atrial pace trigger signal for generating and delivering a left atrial pacing pulse to said left atrial lead means;

whereby an excessive conduction delay between a spontaneous or evoked depolarization in the right atrium and the conducted depolarization wave in the left atrium is corrected by generation and delivery of a left atrial pacing pulse at the timing out of the left atrial conduction delay window.

24. The four channel pacing system of claim 23, further comprising means for programming said left atrial conduction delay window in a range of 0-100 msec.

25. The four channel pacing system of claim 23, further comprising:

right atrial blanking means for preventing the sensing of spontaneous and evoked cardiac depolarizations in the right atrium and the provision of a right atrial sensed event signal in response thereto for the duration of a right atrial blanking period in response to the generation of right and left atrial pacing pulses and a ventricular pacing pulse; and

left atrial blanking means for preventing the sensing of spontaneous and evoked cardiac depolarizations in the left atrium and the provision of a left atrial sensed event signal in response thereto for the duration of a left atrial blanking period in response to the generation of right and left atrial pacing pulses and a ventricular pacing pulse.

26. The four channel pacing system of claim 23, wherein said means for timing a right heart AV delay from a right atrial sensed event signal or a right atrial pacing pulse and providing a ventricular pace trigger signal upon the time out of the right heart AV delay further comprises means for timing a right heart sensed AV delay from a left atrial sensed event signal or a right heart paced AV delay from a right atrial pacing pulse and providing a ventricular pace trigger signal upon the time out of the either the right heart sensed or paced AV delay.

27. The four channel pacing system of claim 23, wherein said means for timing a right heart AV delay from a right atrial sensed event signal or a right atrial pacing pulse and providing a ventricular pace trigger signal upon the time out of the right heart AV delay further comprises means for timing a left heart AV delay from a left atrial sensed event signal or a left atrial pacing pulse and providing a ventricular pace trigger signal upon the time out of the left heart AV delay.

28. The four channel pacing system of claim 27, wherein said means for timing a left heart AV delay from a left atrial sensed event signal or a left atrial pacing pulse further comprises means for timing a left heart sensed AV delay from a left atrial sensed event signal or a left heart paced AV delay from a left atrial pacing pulse and providing a ventricular pace trigger signal upon the time out of the either the left heart sensed or paced AV delay.

29. The four channel pacing system of claim 23, further comprising:

left ventricular lead means for locating first and second left ventricular pace/sense electrodes in relation with the left ventricle;

left ventricular sensing means for sensing spontaneous and evoked cardiac depolarizations in the left ventricle across said left ventricular pace/sense electrodes and providing a left ventricular sensed event signal;

means for timing a left conduction delay window from a right ventricular sensed event signal or from generation of a right ventricular pacing pulse and providing a left ventricular pace trigger signal at the expiration of the left ventricular conduction delay window;

means for terminating the timing out of the left ventricular conduction delay window in response to a left ventricular sensed event signal; and

left ventricular pacing pulse output means coupled with said left ventricular pace/sense electrodes and responsive to said left ventricular pace trigger signal for generating and delivering a left ventricular pacing pulse to said left ventricular lead means;

whereby an excessive conduction delay between a spontaneous or evoked depolarization in the right ventricle and the conducted depolarization wave in the left ventricle is corrected by generation and delivery of a left ventricular pacing pulse at the timing out of the left ventricular conduction delay window.

30. The pacing system of claim 29, further comprising means for programming said left ventricular conduction delay window in a range of 0-100 msec.

31. The four channel pacing system of claim 29, further comprising:

right ventricular blanking means for preventing the sensing of spontaneous and evoked cardiac depolarizations in the right ventricle and the provision of a right ventricular sensed event signal in response thereto for the duration of a right ventricular blanking period in response to the generation of right and left atrial and ventricular pacing pulses; and

left ventricular blanking means for preventing the sensing of spontaneous and evoked cardiac depolarizations in the left ventricle and the provision of a left ventricular sensed event signal in response thereto for the duration of a left ventricular blanking period in response to the generation of right and left atrial and ventricular pacing pulses.

32. The pacing system of claim 29, further comprising means for programming said left ventricular conduction delay window in a range of 0-100 msec.