A contraction of the heart muscle that is out of normal timing. An ectopic heartbeat happens shortly after a normal beat and is followed by a longer than usual interval before the next one.
Ectopic beats can arise in a healthy heart and can be symptomless. Multiple ectopic beats can create palpitations (awareness of forceful or rapid heartbeat). When occurring after a myocardial infarction (heart attack), these multiple beats are a sign of damaged heart muscle. They could lead to a condition called ventricular fibrillation, in which there is an uncoordinated, rapid heartbeat, which is potentially life threatening.
Multiple ectopic beats that are creating palpitations, or those that occur after a myocardial infaraction, are usually treated with an antiarrhythmic drug.