Abstract: A tachycardia control pacer in which at least one scanned pulse is generated following each tachycardia confirmation, and the last-used pulse timing is retained following the next tachycardia termination for subsequent first use following the next tachycardia confirmation. The tachycardia termination detecting circuit does not respond to the time interval between at least the first two heartbeats following a generated pulse, to prevent a false determination of tachycardia termination due to the excessive pauses which sometimes occur immediately after pacing despite the fact that tachycardia has not terminated.

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.

Abstract: A pacer for controlling tachycardia, in which the coupled interval is scanned as well as the initial delay. The time parameters which are successful in terminating the condition are stored so that upon confirmation of another tachycardia event, the previously successful time parameters are the first ones to be tried. The unit also allows tachycardia to be induced by the physician so that the parameters which are programmable can be adjusted for optimum performance following a subsequent naturally occurring tachycardia confirmation.