Ventricular assist device

A Ventricular assist device, or VAD, is a mechanical device that is used to partially or completely replace the function of a failing heart. Some VADs are intended for short term use, typically for patients recovering from heart attacks or heart surgery, while others are intended for long term use (months to years and in some cases for life), typically for patients suffering from congestive heart failure.

There is also a portable one for slightly stronger hearts but it does have its limits. It uses batteries.