Sudden cardiac death (SCD), caused by ventricular fibrillation, poses the greatest threat of all arrhythmias, and accounts for half of all cardiac deaths. In VF, the heartbeat is rapid and chaotic, which prevents the lower heart chambers, or ventricles, from pumping blood to the brain or body.
During VF, the blood pressure falls to zero, and the person falls unconscious in seconds. The lack of blood and oxygen throughout the body, and especially to the brain, is deadly within a few minutes if not treated promptly with defibrillation (shock).
Sometimes, VF can happen during a heart attack (myocardial infarction), because the heart muscle is irritated by the sudden blockage of an artery. VF can also happen at other times, and be caused by previous heart damage or an inherited (genetic) heart condition. It is important to realize that VF is an electrical disorder of the heart (not the same thing as a “heart attack”) and may or may not be related to a problem with clogged arteries that supply the heart with blood.
