Definition: A cardiac arrest occurs when the heart suddenly stops beating, usually due to an cardiac arrhythmia. The arrhythmias that most commonly cause cardiac arrest are ventricular tachycardia (VT) and ventricular fibrillation (VF).
Loss of consciousness invariably occurs within a few seconds of the onset of a cardiac arrest, and unless cardiopulmonary resuscitation is begun within a very few minutes, death rapidly ensues. When cardiac arrest results in death, "sudden cardiac death" (SCD) is said to have occurred. More than 1,000 Americans each day die from SCD.
