Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
173 words
A timing circuit for a heart pacemaker having atrial and ventricular terminal means for connection respectively to the atrium and ventricle of a patient's heart; atrial and ventricular pulse generating means connected for selectively delivering stimulating pulses to said atrial and ventricular terminal means; and atrial sensing means connected to said atrial terminal means, and operative for sensing atrial contractions of the patient's heart; characterised by timing control means operatively connected to said atrial sensing means and said atrial and ventricular pulse generating means, and operative in response to a sensed atrial contraction to cause said ventricular pulse generating means to deliver a stimulating pulse at the end of a first atrial-ventricular delay interval from said sensed atrial contraction, and operative in the absence of sensed atrial contractions to cause said atrial and ventricular pulse generating means to deliver sequential stimulating pulses at a predetermined pacing rate, with said atrial and ventricular sequential pulses being separated in time by a second atrial-ventricular delay interval which is independent of said first atrial-ventricular delay interval.
Claim 2
Dependent Claim
173 words
A timing circuit for a heart pacemaker having atrial and ventricular terminal means for connection respectively to the atrium and ventricle of a patient's heart; atrial and ventricular pulse generating means connected for selectively delivering stimulating pulses to said atrial and ventricular terminal means; and atrial sensing means connected to said atrial terminal means, and operative for sensing atrial contractions of the patient's heart; characterised by timing control means operatively connected to said atrial sensing means and said atrial and ventricular pulse generating means, and operative in response to a sensed atrial contraction to cause said ventricular pulse generating means to deliver a stimulating pulse at the end of a first atrial-ventricular delay interval from said sensed atrial contraction, and operative in the absence of sensed atrial contractions to cause said atrial and ventricular pulse generating means to deliver sequential stimulating pulses at a predetermined pacing rate, with said atrial and ventricular sequential pulses being separated in time by a second atrial-ventricular delay interval which is independent of said first atrial-ventricular delay interval.
Claim 3
Dependent Claim
143 words
A timing circuit. as claimed in claim 1 wherein said timing control means comprises a first atrial-ventricular delay timer, operatively connected to said atrial sensing means and operatively connected for causing said ventricular pulse generating means to deliver a stimulating pulse after an atrial-ventricular time delay following a sensed atrial contraction; a lower rate limit timer operative, in the absence of a sensed atrial contraction, to cause said atrial pulse generating means to deliver a stimulating pulse at the end of a predetermined time interval from a previous ventricular stimulating pulse; and a second atrial-ventricular delay timer operatively connected for actuation in the event of an atrial stimulation pulse caused by said lower rate limit timer, and operatively connected for causing said ventricular pulse generating means to deliver a ventricular stimulation pulse following a second atrial-ventricular time delay from said atrial stimulation pulse.
Claim 4
Dependent Claim
20 words
A timing circuit as claimed in claim 2 wherein said second time delay is longer than said first time delay.
Claim 5
Dependent Claim
45 words
A timing circuit as claimed in claim 2 or 3 further including ventricular sensing means for sensing ventricular contractions of the patient's heart and wherein said lower rate limit timer is adapted for timing its predetermined time period from a sensed or stimulated ventricular contraction.
Claim 6
Dependent Claim
46 words
A timing circuit as claimed in claim 4 wherein said ventricular sensing means is operatively connected to said lower rate limit timer and said first and second atrial- ventricular delay timers for resetting each of said timers in response to a sensed or stimulated ventricular contraction.
Claim 7
Dependent Claim
30 words
A timing circuit as claimed in claim 2, 3, 4 or 5 including means for programming said first atrial-ventricular delay timer for programming the duration of said first time delay.
Claim 8
Dependent Claim
27 words
A timing circuit as claimed in claim 6 further including programming means connected for programming said second __ atrial-ventricular delay timer for programming said second time delay.
Claim 9
Dependent Claim
13 words
A heart pacemaker including a timing circuit as claimed in any preceding claim.