Device and method for ventricular tracking and pacing

• US 6,256,536 B1
• Filed: 05/25/1999
• Issued: 07/03/2001
• Est. Priority Date: 04/04/1997
• Status: Expired due to Term

• Current Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Original Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Inventors: Kramer, Andrew P.
• Primary Examiner(s): EVANISKO, GEORGE ROBERT
• Application Number:
  US09/318,057
• Time in Patent Office: 770 Days
• Field of Search: 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

A device and method for multi chamber pacing a patient'"'"'s heart having heart failure and intrinsic conduction wherein ventricular tracking is used to pace the ventricle when the sinus rate exceeds a preset atrial maximum tracking rate. The ventricular tracking pacemaker increases the range of pacing the ventricle. The ventricular tracking minimizes the loss of ventricular pacing caused by intrinsic conduction when the sinus rate is below an atrial maximum tracking rate, and it induces a new ventricular pacing behavior for sinus rates above the atrial maximum tracking rate without any significant pacing hysteresis as the sinus rate returns towards the lower rate limit.

Claims

1. A method for pacing a ventricle of a patient'"'"'s heart using a pacemaker which senses and tracks independently atrial and ventricular depolarization events and includes a plurality of programmed timing and pacing intervals, said method comprising the steps of:

a) sensing and tracking intrinsic conduction transmitted from an atrium of the patient'"'"'s heart;

then

b) simultaneously with tracking the conduction transmitted from the atrium, sensing and tracking intrinsic conduction transmitted from a ventricle of the patient'"'"'s heart;

then

c) identifying an R-wave from the sensed and tracked intrinsic conduction transmitted from the ventricle of the patient'"'"'s heart and determining a sinus rate of the patient'"'"'s heart from the sensed and tracked intrinsic conduction transmitted from the ventricle;

d) once the R-wave is identified, initiating an RV delay interval and a post ventricular atrial refractory period (PVARP) from a moment when the R-wave is identified;

e) from the moment when the R-wave is identified, detecting a sensed P-wave from the intrinsic conduction transmitted from the atrium of the patient'"'"'s heart;

f) continuing the RV timing interval and PVARP following step b) so long as a second R-wave from the ventricle of the patient'"'"'s heart is not sensed and tracked; and

g) stimulating the ventricle at the end of the RV delay interval, so long as a sensed P-wave is detected during PVARP, wherein stimulating the ventricle is at a pre-selected ratio of prior paced to sensed R-wave when the sinus rate exceeds an atrium maximum tracking rate and is less than a ventricular maximum tracking rate.

2. The method as recited in claim 1, further including the steps of determining a sinus rate of the patient'"'"'s heart from at least one of the sensed and tracked intrinsic conduction transmitted from the ventricle and the sensed and tracked intrinsic conduction transmitted from the atrium, and inhibiting the stimulation to the ventricle when the sinus rate exceeds a ventricular maximum tracking rate.

3. The method as recited in claim 1, further including the step of inhibiting the stimulation to the ventricle when a P-wave is tracked after the end of the PVARP but during the RV delay interval.

4. The method as recited in claim 1, wherein steps a)-e) are repeated when a second R-wave from the ventricle of the patient'"'"'s heart is sensed during the RV delay interval.

5. A method for stimulating a ventricle of a patient'"'"'s heart using a cardiac rhythm management device which senses and tracks independently atrial and ventricular depolarization events and includes a controller having a plurality of programmed timing and pacing intervals, said method comprising the steps of:

a) setting the programmed timing interval of the controller to a timing sequence protocol having a preset post ventricular atrial refractory period (PVARP) timing interval and a preset time delay period (RV) timing interval;

then

b) sensing for and sensing a first intrinsic conduction transmitted from a preselected ventricle of the patient'"'"'s heart, and determining an intrinsic ventricular rate, wherein the RV timing interval is set less than the determined intrinsic ventricular rate;

then

c) initiating the PVARP and RV timing intervals;

then

d) sensing for an intrinsic conduction transmitted from a preselected atrium of the patient'"'"'s heart; and

then

e) stimulating the ventricle at the end of the RV interval if intrinsic conduction of the preselected atrium is sensed before the end of the PVARP timing interval.

6. The method according to claim 5, further including, after step c, the steps of sensing for a second intrinsic conduction transmitted from the preselected ventricle of the patient'"'"'s heart, and if the second intrinsic conduction is sensed, then ending the PVARP and RV timing intervals and repeat steps b)-e).

7. The method according to claim 5, further including, after step e), the steps of initiating an atrial ventricular delay timing interval, if an intrinsic conduction of the preselected atrium is sensed after the end of the PVARP timing interval but before the end of the RV timing interval.

8. The method according to claim 5, wherein a time for stimulating the ventricle at the end of the RV interval is dynamically extended to thereby maintain a preset delay between atrial sense and a ventricular pace.

9. The method according to claim 5, further including, if intrinsic conduction of the preselected atrium is sensed before the end of PVARP, initiating a preset refractory atrial to ventricular (RAV) delay, and stimulating the ventricle at the end of the RAV delay.

10. The method according to claim 9, wherein the ventricle is stimulated as long as the RAV delay ends before an intrinsic ventricular conduction is sensed.

11. The method according to claim 9, wherein the ventricle is stimulated at the end of the RAV delay, unless the RAV delay ends prior to the end of the RV interval, in which case the ventricle is stimulated at the end of the RV interval.

12. The method according to claim 11, wherein the ventricle is stimulated as long as the end of the RV interval ends before an intrinsic ventricular conduction is sensed.

13. The method according to claim 5, wherein the ventricle is stimulated further dependant upon a second sensed intrinsic atrial conduction occurring prior to the beginning of the RV timing interval.