Federal health officials have cleared a wearable heart-zapping device for children who are at risk of deadly irregular heartbeats.

The LifeVest is intended for children who need round-the-clock heart monitoring but cannot receive an implantable device, due to health problems or parental objections. Defibrillators correct dangerous heart rhythms by jolting the heart with an electrical current.

Most adults at risk of cardiac arrest have the life-saving devices surgically implanted. External defibrillators are also used in emergencies, but they must be operated by a second person.

LifeVest - which includes an electrode belt and a heart monitor- is already approved for adults. It is intended for patients who weigh at least 41 pounds.

Food and Drug Administration officials said Thursday's approval would help doctors safely prescribe the device for children.