A pacemaker is a small device with two parts — a generator and wires (leads, or electrodes) — that's placed under the skin in your chest to help control your heartbeat.
People may need a pacemaker for a variety of reasons — mostly due to one of a group of conditions called arrhythmias, in which the heart's rhythm is abnormal.
Normal ageing of the heart may disrupt your heart rate, making it beat too slowly. Heart muscle damage resulting from a heart attack is another common cause of disruptions of your heartbeat.
Some medications can affect your heart rate as well. For some, genetic conditions cause an abnormal heart rate. Regardless of the underlying cause of an abnormal heart rate, a pacemaker may fix it.
A pacemaker can often be implanted in your chest with minor surgery. You may need to take some precautions in your daily life after your pacemaker is installed.
Why it's done
Pacemakers are implanted to help control your heartbeat. They can be implanted temporarily to treat a slow heartbeat after a heart attack, surgery or overdose of medication.
Pacemakers can also be implanted permanently to correct a slow heartbeat (bradycardia) or, in some cases, to help treat heart failure.
Smaller pacemakers about the size of a pill have been developed and are currently undergoing clinical trials. This new, leadless device can be implanted directly into the heart, where it emits an electrical impulse to control the heartbeat. Because a lead isn't required, this device can minimize the risk of infection and speed recovery time.
What a pacemaker does
An implanted electronic pacemaker mimics the action of your natural pacemaker. An implanted pacemaker consists of two parts:
- The pulse generator. This small metal container houses a battery and the electrical circuitry that regulates the rate of electrical pulses sent to your heart.
- Leads (electrodes). One to three flexible, insulated wires are each placed in a chamber, or chambers, of your heart and deliver the electrical pulses to adjust your heart rate.
Pacemakers monitor your heartbeat and, if it's too slow, the pacemaker will speed up your heart rate by sending electrical signals to your heart. In addition, most pacemakers have sensors that detect body motion or breathing rate, which signals the pacemaker to increase your heart rate during exercise to meet your body's increased need for blood and oxygen.