Abstract An improved pacer for controlling tachycardia. Following tachycardia confirmation, a burst of at least three stimulating pulses is generated. The time intervals between successive pulses decrease by a fixed decrement; thus the rate of the pulses increases during each cycle of operation, the burst being more accurately characterized as a "chirp". The first pulse is generated following the last heartbeat which is used to confirm tachycardia at a time which is actually dependent on the rate of the heartbeats in the tachycardia episode; the time delay between the last heartbeat and the first pulse in the chirp is equal to the time interval between the last two heartbeats, less the fixed decrement which characterizes successive time intervals between stimulating pulses. Because successive pulses are generated at an increasing rate, and because the first pulse is generated at a time which is actually dependent upon the tachycardia rate, there is a greater likelihood that tachycardia termination will be achieved.
A tachycardia control pacer comprising means for confirming tachycardia, means responsive to each operation of said confirming means for generating a sequence of at least three heart stimulating pulses, means for controlling successive heart stimulating pulses in said sequence to be generated after decreasing time intervals, means for registering the last interval between heartbeats prior to the operation of said confirming means, means for controlling the first pulse in said sequence to be generated at the end of a first time interval following the last heartbeat which is equal to said registered interval less a predetermined value, the successive pulses in said sequence being generated after decreasing time intervals starting with said first time interval, means for controlling the same number of pulses to be generated during each pulse sequence, and means for preventing the pulses toward the end of any sequence from being generated after time intervals which are less than a predetermined interval.
Claim 2
Dependent Claim
155 words
A tachycardia control pacer comprising means for confirming tachycardia, means responsive to each operation of said confirming means for generating a sequence of at least three heart stimulating pulses, means for controlling successive heart stimulating pulses in said sequence to be generated after decreasing time intervals, means for registering the last interval between heartbeats prior to the operation of said confirming means, means for controlling the first pulse in said sequence to be generated at the end of a first time interval following the last heartbeat which is equal to said registered interval less a predetermined value, the successive pulses in said sequence being generated after decreasing time intervals starting with said first time interval, means for controlling the same number of pulses to be generated during each pulse sequence, and means for preventing the pulses toward the end of any sequence from being generated after time intervals which are less than a predetermined interval.
Claim 3
Dependent Claim
24 words
A tachycardia control pacer in accordance with claim 1 wherein successive time intervals between the pulses in said sequence differ by said predetermined value.
Claim 4
Dependent Claim
40 words
A tachycardia control pacer in accordance with claim 1 wherein said confirming means operates to confirm tachycardia responsive to a predetermined number of heartbeats occurring in succession, each of which occurs after the preceding heartbeat within a predetermined time period.