Abstract: A method and device for detecting a cardiac event that includes sensing cardiac electrical signals representative of electrical activity of a heart of a patient, detecting the cardiac event in response to the sensed cardiac signals, determining an indication of signal reliability corresponding to the sensed cardiac signals as being one of a reliable signal and a not reliable signal, and switching operation of the device between a first mode of determining whether the sensed signal is one of treatable and not treatable and a second mode of determining whether the sensed signal is one of treatable and not treatable in response to the determined indication of signal reliability.

Abstract: A cardiac medical device and associated method control delivery of dual chamber burst pacing pulses in response to detecting tachycardia. In one embodiment, a single chamber pacing pulse is delivered in response to detecting a tachycardia. Dual chamber pacing pulses are delivered subsequent to the single chamber pacing pulse. An intrinsic depolarization is sensed subsequent to delivering the dual chamber pacing pulses. The tachycardia episode is classified in response to the sensed intrinsic depolarization.