Method and apparatus for detecting non-sustaining ventricular tachyarrhythmia

An implantable medical device, comprising:

• a sensing circuit configured to sense a cardiac signal;
• and
• a controller configured to control delivery of an anti-tachyarrhythmia therapy, the controller including:
• a tachyarrhythmia detector coupled to the sensing circuit, the tachyarrhythmia detector configured to detect an initiation event indicative of a tachyarrhythmia episode from the cardiac signal, start a tachyarrhythmia detection and classification process in response to a detection of the initiation event, and to restart or extend the tachyarrhythmia detection and classification process in response to a detection of an inhibitory event indicative of a need to inhibit the delivery of the anti-tachyarrhythmia therapy, the tachyarrhythmia detection and classification process determining whether the tachyarrhythmia episode sustains and is to be treated by the anti-tachyarrhythmia therapy;
• a beat detector coupled to the sensing circuit, the beat detector configured to detect heart beats from the cardiac signal;
• a heart rate detector coupled to the beat detector, the heart rate detector configured 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 configured to classify each beat of the detected heart beat as a fast beat in response to the each beat associated with a heart rate within a tachyarrhythmia detection zone and a slow beat in response to the each beat associated with a heart rate below the tachyarrhythmia detection zone or being a paced heart beat;
• and
• an inhibitory event detector coupled to the tachyarrhythmia detector and the beat classifier, the inhibitory event detector including an arrhythmia pattern detector configured to detect a specified pattern including repetitive sequences of the fast and slow beats and indicate a detection of the inhibitory event in response to a detection of the specified pattern.