Patent ID: 7780606

Claim:
A system comprising: an implantable medical device (IMD) comprising: an implantable heart sound sensor operable to produce an electrical signal representative of at least one heart sound, the heart sound associated with mechanical activity of a patient's heart; a heart sound sensor interface circuit coupled to the heart sound sensor to produce a heart sound signal; a tachyarrhythmia detector; and a controller circuit coupled to the heart sound sensor interface circuit and the tachyarrhythmia detector, wherein the controller circuit includes a hemodynamic stability assessment module configured to: determine that at least one episode of ventricular tachyarrhythmia is detected in a subject; initiate, in response to and obtain during the detected episode of tachyarrhythmia, a measurement of hemodynamic stability of the ventricular tachyarrhythmia from the heart sound signal, wherein the measurement of hemodynamic stability is determined using linear prediction; and deem whether the ventricular tachyarrhythmia is stable according to the measurement of hemodynamic stability.