Detection of T-wave alternans phase reversal for arrhythmia prediction and sudden cardiac death risk stratification

A medical device system for classifying a patient's risk for arrhythmias, comprising:

• an electrode to sense a cardiac electrogram (EGM) signal comprising a plurality of T-wave signals;
• sensing circuitry coupled to the electrode to receive and filter the EGM signal;
• and
• a processor coupled to the sensing circuitry and configured to:
• select a first pair of T-wave signals from the plurality of T-wave signals, the selected first pair comprising a first T-wave signal and a second T-wave signal, the second T-wave signal occurring consecutively after the first T-wave signal,
• determine a feature of the first T-wave signal and a feature of the second T-wave signal,
• compute a first difference between the feature of the first T-wave signal and the feature of the second T-wave signal,
• select a second pair of T-wave signals occurring after the first pair of T-wave signals, the selected second pair comprising a third T-wave signal and a fourth T-wave signal, the fourth T-wave signal occurring consecutively after the third T-wave signal,
• determine a feature of the third T-wave signal and a feature of the fourth T-wave signal,
• determine a second difference between the feature of the third T-wave signal and the feature of the fourth T-wave signal,
• compare the first difference and the second difference,
• detect a T-wave alternans phase reversal of a T-wave morphology from an A-B order to a B-A order in response to comparing the first difference and the second difference, and
• classify the patient's arrhythmia risk in response to detecting the phase reversal.