A system and method determining physiological status of a patient. A determination is made whether the patient is sleeping. The amplitude and change in voltage over time of any intramyocardial electrogram is measured for a right ventricle and a left ventricle of a heart of the patient for a predefined number of heartbeats at a specified time interval in response to determining the patient is asleep. The measurements are averaged for the right ventricle and left ventricle. The averaged measurements are transmitted to a receiver for communication to an intended recipient.