Each individual heartbeat is actually a collection of several muscle movements spurred into action by electrical impulses.
The first electrical signal comes from the heart’s own natural pacemaker, the sinoatrial node, comprised of electrically active cells and located in the upper right heart chamber. This node sends a steady stream of electrical signals along a pathway through the heart’s upper chambers. The signals then travel to the electrical bridge – the atrioventricular node – between the upper and lower chambers and, finally, move to the lower chambers.
A problem at any point in the electrical pathway can wreak havoc with the regular beating of a heart. Luckily, an artificial pacemaker – a small, battery -operated device – can take over the role of the heart’s own electrical system, if necessary.