Patent ID: 8260415

Claim:
An implantable medical device for monitoring blood flow pulsatility in a volume of body tissue in a patient, the device comprising: at least two electrodes for sensing cardiac electrical signals; a light source for emitting a light signal, and a light detector for receiving the light signal emitted by the light source and scattered by the volume of body tissue, the light detector emitting a signal correlated to the received light signal, the light detector signal having an alternating current component correlated to pulsatility of blood flow within the volume of body tissue; and a processor configured to receive the cardiac electrical signals, sense events as R-wave events from the cardiac electrical signals, gate the light detector signal for monitoring the alternating current component at a time delay following a sensed R-wave event, receive the gated light detector signal, determine a patient condition in response to the alternating current component of the gated light detector signal, and detect T-wave oversensing in response to the gated light detector signal.