The present invention relates to a medical device including an artificial contractile structure which may be advantageously used to assist the functioning of a hollow organ. The medical device includes an artificial contractile structure including at least one contractile element (100) adapted to contract an organ, in such way that the contractile element (100) is in a resting or in an activated position, at least one actuator designed to activate the contractile structure, and at least one source of energy for powering the actuator. The ratio “current which is needed to maintain the contractile element in its activated position/current which is needed to change the position of the contractile element” is less than 1/500, preferably less than 1/800, and more preferably less than 1/1000.
