There is disclosed a medical device adapted to be implanted in the heart of a patient and operable therein i) as a heart valve; or ii) to assist in the functioning of one of the patient's heart valves; or iii) to monitor the functioning of one of the patient's heart valves. The device includes one or more sensors for sensing a physiologically or clinically relevant parameter of a patient. A telemetric communication device telemetrically transmits data related to a parameter sensed by the sensor to a remote device.