A pulsatile, positive-displacement mechanical circulatory support pump which can be used for assistance or replacement of one or both ventricles. The pump includes a plurality of contractile elements radiating outward from an apex of a compliance chamber, the elements being incorporated in and/or in contact with at least a portion of an outer surface of the compliance chamber. These contractile elements include an electroactive dielectric elastomer or an ion exchange membrane metallic composite. Application of electric field pulses from an implantable electrical energy source such as a pacemaker will cause the contractile elements to compress and expand the compliance chamber.