Helping blood to circulate using a mechanical pump can overcome heart failure and lead some patients to make a full recovery, a study has shown.
Nearly 40% of a group of trial participants fitted with one of the £80,000 battery-operated devices ended up with healthy heart function.
Researchers at the University of Newcastle said the pumps could help solve the shortage of donor hearts.
The devices are usually fitted when patients are waiting for a new organ.
Lead researcher Djordje Jakovljevic, from the Institute of Cellular Medicine at the university, said: "We talk about these devices as a bridge-to-transplant, something which can keep a patient alive until a heart is available for transplantation.
"However, we know that sometimes patients recover to such an extent that they no longer need a heart transplant.
"For the first time what we have shown is that heart function is restored in some patients."
The pump, known as a left ventricular assist device (LVAD), is usually fitted in patients with end stage heart failure.
The trial involved 58 male patients who underwent treadmill tests of their heart fitness.
Of the 16 who recovered enough to have their LVAD pump removed, 38% demonstrated a heart function equal to that of a healthy individual of the same age.
The next stage of the study is to determine why the device is "curing" some patients and identify those who will respond best to having one fitted.