A-V responsive rate adaptive pacemaker
First Claim
1. A cardiac pacemaker, comprising:
- means for measuring the duration of an A-V interval in a heart and providing an output indicative of said measured interval; and
means responsive to said measuring means for applying cardiac stimuli to said heart at a rate related to said measured A-V interval duration.
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Accused Products
Abstract
A microprocessor controlled A-V responsive rate adaptive DDD cardiac pacemaker is disclosed. The pacemaker includes atrial and ventricular sense amplifiers for detecting P-waves and Q-waves respectively, atrial and ventricular stimulus pulse generators, and A-V interval timer times the interval between a P-wave and subsequent Q-wave. The timed interval is used by a pacing interval calculation algorithm to calculate an A-A pacing interval based on one of two linear functions depending upon whether atrial activity is spontaneous or induced. The pacing interval timer times the pacing interval. If no atrial activity is detected, the atrial stimulus pulse generator paces the atrium. The A-V interval timer also times a maximum A-V interval. If no ventricular activity is sensed in the interval, the ventricular stimulus pulse generator paces the ventricle.
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Citations
18 Claims
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1. A cardiac pacemaker, comprising:
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means for measuring the duration of an A-V interval in a heart and providing an output indicative of said measured interval; and means responsive to said measuring means for applying cardiac stimuli to said heart at a rate related to said measured A-V interval duration. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A cardiac pacemaker comprising:
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means for measuring the duration of the A-V interval; means for measuring an atrial pacing escape interval related to said measured A-V interval; means for sensing selected cardiac activity during said measured atrial pacing escape interval; and means for applying a pacing stimulus pulse to the heart if said selected cardiac activity is not detected during said measured atrial pacing escape interval. - View Dependent Claims (9, 10, 11, 12)
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13. A cardiac pacemaker, comprising:
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a sensor means for detecting cardiac atrial and ventricular activity; control circuit means responsive to said sensor means, including first timing means for timing the A-V interval between paced or sensed atrial activity and ventricular sensed activity detected by said sensor means, means for calculating a target pacing interval related to said timed A-V interval, second timing means for timing a current pacing interval, and means for initiating pacing if selected cardiac activity is not detected by said sensor means during said target pacing interval; and pacing stimulus generator means responsive to said control circuit means for generating and delivering pacing stimulus pulses to the heart. - View Dependent Claims (14, 16, 17)
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15. The cardiac pacemaker defined in clam 13, wherein said means for calculating said target pacing interval further comprises:
means for periodically incrementing said target pacing interval to allow extra time for selected spontaneous cardiac activity to occur.
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18. A method of pacing a heart, comprising the steps of:
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(a) starting an A-V interval timer upon detecting natural or paced artrial activity; (b) stopping said A-V interval timer upon detecting natural or paced ventricular activity; (c) calculating a target pacing interval related to the timed A-V interval; (d) timing said target pacing interval; (e) detecting selected cardiac activity during said target pacing interval; and (f) generating and delivering a pacing stimulus pulse to the heart if said selected cardiac activity is not detected during said target pacing interval.
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Specification