Patent ID: 8827895

Claim:
A system comprising: an implantable device including: an implantable cardiac signal sensing circuit, configured to provide a sensed depolarization signal from a ventricle and a sensed depolarization signal from an atrium; and a controller circuit communicatively coupled to the implantable cardiac signal sensing circuit, wherein the controller circuit includes: a one-to-one detector circuit configured to: measure cardiac depolarization intervals of the atrium and the ventricle; and determine whether a relationship of atrial (A-A) depolarizations to ventricular (V-V) depolarizations is substantially one-to-one; a tachyarrhythmia discrimination circuit configured to: detect an episode of tachyarrhythmia when the relationship atrial depolarizations to ventricular depolarizations is substantially one-to-one; generate an indication of VT when detecting one of a shortening or prolonging of an A-A interval during the episode that is immediately preceded by the same one of a shortening or prolonging of a V-V interval during the episode; generate an indication of a supra-ventricular tachycardia (SVT) event when detecting one of a shortening or prolonging of an A-A interval that immediately precedes the same one of a shortening or prolonging of the V-V interval during the episode; and classify the tachyarrhythmia episode as one of VT or SVT according to the generated indications of VT and SVT.