-- Question: What is a pacemaker and how does it work?
Answer :Pacemakers are electronic devices that are designed to prevent the heart from going too slowly. They're used primarily in people whose normal pacemakers are either diseased or suppressed by drugs, or in whom the connection between the upper and lower chambers of the heart -- what's called the cardiac conduction system -- may be abnormal, producing a situation known as heart block.
So the primary purpose of a pacemaker is to measure each heartbeat and to actually inject an electrical stimulus into the heart which causes a heartbeat if the heartbeat becomes too slow. Pacemakers do not prevent rapid heartbeats. In some situations, particularly when they exist in an implantable defibrillator, they may be used to treat rapid heart beats, but their primary indication is to prevent the heart from going too slowly.