Medical device and method for detecting arrhythmia

A method comprising:

• sensing a plurality of cardiac electrical signals;
• sensing ventricular event signals from the plurality of cardiac electrical signals;
• performing a first analysis of ventricular event signals sensed during a long pause detection interval for detecting a suspected long pause in ventricular activity;
• performing a second analysis of ventricular event signals sensed by the sensing circuit for detecting suspected tachyarrhythmia undersensing;
• obtaining a first cardiac signal segment from the sensed plurality of cardiac electrical signals in response to detecting at least one of a suspected long pause based on the first analysis or suspected tachyarrhythmia undersensing based on the second analysis;
• performing a morphology analysis of the first cardiac signal segment;
• classifying the first cardiac signal segment as being one of ventricular tachyarrhythmia, non-ventricular tachyarrhythmia or asystole based on the morphology analysis;
• in response to the first cardiac signal segment being classified as ventricular tachyarrhythmia, restarting the long pause detection interval;
• and
• in response to at least the first cardiac signal segment being classified as one of non-ventricular tachyarrhythmia or asystole, delivering a cardiac pacing pulse.

A non-transitory, computer readable medium storing a set of instructions that, when executed by control circuitry of a medical device, cause the medical device to:

• sense a plurality of cardiac electrical signals;
• sense ventricular event signals from the plurality of cardiac electrical signals;
• perform a first analysis of ventricular event signals sensed during a long pause detection interval for detecting a suspected long pause in ventricular activity;
• perform a second analysis of ventricular event signals sensed by the sensing circuit for detecting suspected tachyarrhythmia undersensing;
• obtain a cardiac signal segment from the sensed plurality of cardiac electrical signals in response to detecting at least one of a suspected long pause based on the first analysis or suspected tachyarrhythmia undersensing based on the second analysis;
• perform a morphology analysis of the cardiac signal segment;
• classify the cardiac signal segment as being one of ventricular tachyarrhythmia, non-ventricular tachyarrhythmia or asystole based on the morphology analysis;
• in response to the cardiac signal segment being classified as ventricular tachyarrhythmia, restart the long pause detection interval;
• and
• in response to at least the cardiac signal segment being classified as one of non-ventricular tachyarrhythmia or asystole, deliver a cardiac pacing pulse.