This invention is an implanted extracardiac device for supplementing blood circulation which comprises an implanted blood flow lumen, a blood flow increasing mechanism, and a control unit. Its design improves blood circulation when the blood flow increasing mechanism is operating, without hindering native blood flow when the mechanism is not operating. This device improves circulation without intruding on cardiac tissue or weakening the heart by completely supplanting cardiac function. Also, since the device allows native blood flow when the blood flow increasing mechanism is not in operation, it requires less power and can enable more patient mobility.
