A medical device including an artificial contractile structure, which may be advantageously used to assist the functioning of a hollow organ, is provided. The medical device includes an artificial contractile structure including at least one contractile element adapted to contract an organ in such a way that the contractile element 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 actuator includes an electromotor and a transmission element linking the electromotor to the contractile element, the transmission element being configured to transmit to the contractile element a force induced by the electromotor. The electromotor includes an electric motor, a gear head connected to the motor, a lead screw cooperating with a nut mounted on the lead screw, the lead screw or the nut being connected to the transmission element and cooperating with the gear head to transmit the force induced by the electromotor on the transmission element. 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.
