Your heart is a muscle that pumps oxygen-rich blood throughout the body. The heart has four chambers: the upper two are called the right atrium and left atrium, and the lower two are the right ventricle and the left ventricle. Between every chamber, there is a valve that helps keep blood flowing in the right direction.
The heart also has an electrical system that sends signals to expand and contract or beat. This signal helps your heart beat to a regular rhythm. These electrical signals are controlled by two groups of special cells called the sinoatrial node (SA Node) and atrioventricular node (AV Node).
The regular rhythm of your heart helps to pump blood first to the lungs, where it becomes filled with oxygen and nutrients. The oxygenated blood is then circulated throughout the body.
When there is a problem with the electrical system of the heart, this causes the heart to beat with an irregular rhythm and can lead to sudden cardiac arrest.
*Figures were produced using Servier Medical Art, www.servier.com
