An electronic device implanted on a patient’s heart, or which a patient wears attached to the chest, which stimulates and regulates the heartbeat.
The natural pacemaker is the sinoatrial node, found at the base of the heart. The heart normally controls its rate and rhythm; heart block occurs when impulses cannot reach all parts of the heart. This may lead to arrhythmia, or even cause the heart to stop. Artificial pacemakers may then be used; in the United Kingdom these are required for around one person in every 2,000 of the population. Usually powered by mercury or lithium batteries, and lasting up to 15 years, they are either fixed to the outside of the chest or implanted in the armpit, and connected by a wire passing through a vein in the neck to the heart. Normally adjusted to deliver 65-75 impulses a minute, they also ensure a regular cardiac rhythm. Patients with pacemakers may be given a driving licence provided that their vehicle is not likely to be a source of danger to the public, and that they are receiving adequate and regular medical supervision from a cardiologist.
A group of cells that are at the top of the right atrium and that control the heartbeat.