Patent ID: 7689282

Claim:
An implantable medical device, comprising: a sensing circuit to sense a cardiac signal; and a controller adapted to control a delivery of an anti-tachyarrhythmia therapy, the controller including: a tachyarrhythmia detector coupled to the sensing circuit, the tachyarrhythmia detector adapted to detect a predetermined type initiation event indicative of a tachyarrhythmia episode from the cardiac signal, to start a tachyarrhythmia detection and classification process in response to the detection of the predetermined type initiation event, and to restart or extend the tachyarrhythmia detection and classification process in response to a detection of a predetermined type inhibitory event, the tachyarrhythmia detection and classification process determining whether the tachyarrhythmia episode sustains and is to be treated by the delivery of the anti-tachyarrhythmia therapy; a beat detector coupled to the sensing circuit, the beat detector adapted to detect heart beats from the cardiac signal; a heart rate detector coupled to the beat detector, the heart rate detector adapted to detect a heart rate associated with each of the detected heart beats; a beat classifier coupled to the heart rate detector, the beat classifier adapted to classify each of the detected heart beat as one of a fast beat and a slow beat using the heart rate associated with the each of the detected heart beats, the fast beat being a detected heart beat associated with a heart rate within a tachyarrhythmia detection zone, the slow beat being one of a detected heart beat associated with a heart rate below the tachyarrhythmia detection zone and a paced heart beat; and an inhibitory event detector coupled to the tachyarrhythmia detector and the beat classifier, the inhibitory event detector adapted to detect the predetermined type inhibitory event from the cardiac signal, the predetermined type inhibitory event indicative of a need to inhibit the delivery of the anti-tachyarrhythmia therapy, the inhibitory event detector comprises an arrhythmia pattern detector adapted to detect a predetermined type arrhythmia pattern and indicate the detection of the predetermined type inhibitory event when the predetermined type arrhythmia pattern is detected, the predetermined type arrhythmia pattern including repetitive beat sequences each including a first number (F) of the fast beats followed by a second number (S) of the slow beats, wherein in the numbers F and S fall into one or more predetermined patterns.