Patent ID: 8391979

Claim:
An implantable medical device, comprising: a cardiac electrode for sensing cardiac depolarization signals; an optical sensor for providing a signal corresponding to light attenuation by a volume of blood perfused tissue; a control module coupled to the optical sensor controlling the light emitted by the optical sensor; a monitoring module receiving an optical sensor output signal and measuring light attenuation; a tissue electrode for stimulating the volume of blood perfused tissue; a pulse generator coupled to the tissue electrode for delivering electrical stimulation to the volume of blood-perfused tissue; and a processor coupled to the cardiac electrode and the monitoring module and configured to detect an arrhythmia in response to the depolarization signals, compute a tissue oxygenation measurement in response to detecting the arrhythmia, control the pulse generator to deliver electrical stimulation to the volume of blood-perfused tissue in response to detecting the arrhythmia, determine one of a rate of tissue oxygenation decline and a rate of tissue oxygenation recovery, and detect a hemodynamic status of the arrhythmia in response to at least one of the rate of tissue oxygenation decline and the rate of tissue oxygenation recovery.