Pacemaker and method of operating same that provides functional atrial cardiac pacing with ventricular support
First Claim
1. A method of controlling the operation of a dual-chamber electronic pacemaker, the pacemaker having pulse generating means for selectively generating an atrial stimulation pulse (A-pulse) and a ventricular stimulation pulse (V-pulse);
- timing means for generating specified time intervals, including an AV interval;
sensing means for sensing selected cardiac events, including P-waves and R-waves;
means for controlling the pulse generating means as a function of whether the sensing means senses certain prescribed events during a given time interval generated by the timing means, the method comprising;
(a) measuring an AR interval defined as a time interval between an atrial event and a sensed R-wave, the atrial event comprising either the generation of an A-pulse or the sensing of a P-wave;
(b) averaging the AR interval over a prescribed number of cardiac cycles to define a "learned" AR interval, the "learned" AR interval corresponding to a natural conduction time of the heart;
(c) determining whether an R-wave is naturally conducted by comparing the AR interval of an R-wave which occurs during an original AV interval with the "learned" AR interval, the original AV interval comprising a time interval generated by the timing means that commences with an atrial event and terminates a prescribed period of time thereafter;
(d) shortening the AV interval by a specified amount to produce a short AV interval whenever AV conduction is determined not to be present; and
(e) returning the AV interval to the original AV interval whenever AV conduction has returned, and keeping the AV interval at its short value whenever AV conduction has not returned.
2 Assignments
0 Petitions
Accused Products
Abstract
A special type of AV/PV hysteresis is provided in a dual-chamber pacemaker. A long AV delay is initially provided, thereby affording as much opportunity as possible for natural AV conduction to occur. Such long AV delay is automatically shortened should AV block occur. Periodic scanning for the return of AV conduction (absence of AV block) is performed so that the AV delay can be returned to its long value as soon as possible. In one embodiment, the pacemaker "learns" the natural conduction time (AR interval) of the patient and thereafter uses such learned natural conduction time as a reference against which subsequently measured AR intervals are compared to better distinguish conducted ventricular contractions from ectopic, pathologic, or other nonconducted ventricular contractions (e.g., PVC'"'"'s). If the measured AR interval is approximately the same as the "learned" AR interval, then the R-wave at the conclusion of the measured AR interval is presumed to be a conducted R-wave that signals the return of AV conduction, and the AV delay is lengthened back to its original value. If, on the other hand, the measured AR interval is significantly different than the "learned" natural conduction time, then the R-wave at the conclusion of the measured AR interval is presumed to be a nonconducted R-wave, and the AV delay is kept short. In other embodiments, other techniques are used to distinguish a conducted R-wave from a nonconducted R-wave.
206 Citations
20 Claims
-
1. A method of controlling the operation of a dual-chamber electronic pacemaker, the pacemaker having pulse generating means for selectively generating an atrial stimulation pulse (A-pulse) and a ventricular stimulation pulse (V-pulse);
- timing means for generating specified time intervals, including an AV interval;
sensing means for sensing selected cardiac events, including P-waves and R-waves;
means for controlling the pulse generating means as a function of whether the sensing means senses certain prescribed events during a given time interval generated by the timing means, the method comprising;(a) measuring an AR interval defined as a time interval between an atrial event and a sensed R-wave, the atrial event comprising either the generation of an A-pulse or the sensing of a P-wave; (b) averaging the AR interval over a prescribed number of cardiac cycles to define a "learned" AR interval, the "learned" AR interval corresponding to a natural conduction time of the heart; (c) determining whether an R-wave is naturally conducted by comparing the AR interval of an R-wave which occurs during an original AV interval with the "learned" AR interval, the original AV interval comprising a time interval generated by the timing means that commences with an atrial event and terminates a prescribed period of time thereafter; (d) shortening the AV interval by a specified amount to produce a short AV interval whenever AV conduction is determined not to be present; and (e) returning the AV interval to the original AV interval whenever AV conduction has returned, and keeping the AV interval at its short value whenever AV conduction has not returned. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
- timing means for generating specified time intervals, including an AV interval;
-
17. A dual-chamber electronic pacemaker, comprising:
-
pulse generating means for selectively generating an atrial stimulation pulse (A-pulse) and a ventricular stimulation pulse (V-pulse); timing means for generating specified time intervals, including an AV interval; sensing means for sensing selected cardiac events, including P-waves and R-waves; control means for controlling the pulse generating means as a function of whether the sensing means senses certain prescribed events during a given time interval generated by the timing means, the control means including; means for measuring an AR interval defined as a time interval between an atrial event and a sensed R-wave, the atrial event comprising either a stimulation A-pulse or a sensed P-wave; means for averaging the AR interval over a prescribed number of cardiac cycles to define a "learned" AR interval, the "learned" AR interval corresponding to a natural conduction time of the heart; means for determining whether a sensed R-wave is a conducted R-wave by comparing the AR interval of an R-wave which occurs during an original AV interval with the "learned" AR interval, the original AV interval comprising a time interval generated by the timing means that commences with an atrial event and terminates a prescribed period of time thereafter; means for shortening the AV interval by a specified amount to produce a short AV interval whenever AV conduction is determined not to be present; and means for returning the AV interval to a long AV interval whenever AV conduction has returned, and for keeping the AV interval at its short value whenever AV conduction has not returned. - View Dependent Claims (18, 19, 20)
-
Specification