A device for providing assistance to ventricular systole the device comprising a pressuriser and a driver wherein the pressuriser is adapted to be able to apply localised pressure to only the external wall of one ventricle or a portion thereof and the driver is operatively linked to the pressuriser so as to be able to drive a cycle of increased and decreased pressure applied by the pressuriser. The invention also relates to a method of implanting the device and a method of treating cardiac pump failure in which the device is used.
