Patent ID: 8401628

Claim:
An apparatus comprising: an implantable cardiac signal sensing circuit, configured to provide a sensed near-field depolarization signal from a ventricle and to provide a sensed far-field intrinsic atrial signal using at least one of a first far-field atrial sensing channel and a second far-field sensing channel, wherein a far-field atrial sensing channel is configured to receive the far-field intrinsic atrial signal from an electrode location that is outside of an atrium; and a controller circuit communicatively coupled to the cardiac signal sensing circuit, wherein the controller circuit includes: a P-wave detection module configured to detect an atrial depolarization in the sensed far-field intrinsic atrial signal; switch from the first far-field atrial sensing channel to a second far-field atrial sensing channel according to a measurement of the detected atrial depolarization; and a tachyarrhythmia detection module configured to detect an episode of tachyarrhythmia using the sensed near-field ventricular depolarization signal and to determine whether the tachyarrhythmia episode is indicative of supraventricular tachycardia (SVT) using at least one of atrial rate or atrial interval determined using the far-field detected atrial depolarization and using the sensed near-field ventricular depolarization signal.