Patent ID: 8301244

Claim:
An apparatus comprising: an implantable ventricular depolarization sensing circuit configured to provide a sensed ventricular depolarization signal; a timer circuit configured to provide a ventricular time interval between ventricular depolarizations; and a controller circuit communicatively coupled to the ventricular depolarization sensing circuit and the timer circuit, wherein the controller circuit includes a ventricular tachycardia (VT) detection circuit configured to: declare an episode of VT when a number of accelerated beats are detected, wherein an accelerated beat concludes a ventricular time interval having a shorter duration than a specified central tendency of previous ventricular time intervals; determine an estimated onset ventricular time interval using a value of at least one accelerated beat interval when the episode of VT is declared; determine an estimated end ventricular time interval using a value of at least one non-accelerated beat interval when a specified number of non-accelerated beat intervals are detected after the episode of VT is declared; calculate the hysteresis VT detection threshold interval using the estimated onset ventricular time interval and the estimated end ventricular time interval; and deem whether the episode of VT persists using the hysteresis VT detection threshold interval.