Patent ID: 7702384

Claim:
A system comprising: an implantable medical device (IMD) comprising: a ventricular contraction sensing circuit operable to provide a sensed ventricular contraction signal; a timer circuit operable to provide a ventricular time interval between ventricular contractions; a controller circuit coupled to the timer circuit, the controller circuit operable to determine the ventricular contraction rate using the ventricular time interval, and wherein the controller circuit further includes a tachyarrhythmia detection module operable to: determine an average ventricular contraction interval; deem a current heartbeat as an accelerated beat if a difference between a last average ventricular contraction interval (V-V interval) and the current V-V interval is greater than a specified portion of the last average V-V interval; declare tachyarrhythmia, in response to detecting a sudden rate increase, without requiring comparing a ventricular rate or time interval to a respective tachyarrhythmia detection rate or time interval threshold, wherein a sudden rate increase is defined as a specified number of accelerated beats; and exclude an accelerated beat from a determination of the average V-V interval after the specified number of accelerated beats occurs.