Sudden cardiac arrest often occurs because of an underlying heart condition or disease that has not been detected. A sudden cardiac arrest episode has many possible causes. Some conditions or diseases that cause life-threatening arrhythmias that lead to sudden cardiac arrest include coronary artery disease, hypertrophic cardiomyopathy, long QT syndrome, a previous heart attack and Brugada syndrome.
Sudden cardiac arrest and a heart attack refer to different medical conditions. Sudden cardiac arrest occurs because of a malfunction in the heart's electrical system that causes an abnormal heart rhythm (arrhythmia). A heart attack occurs when blood flow to the heart is obstructed by clogged blood vessels (arteries).
Both conditions, however, almost always occur because of other underlying heart problems. Time is important when identifying and treating these conditions. The doctor or emergency medical personnel must immediately identify and diagnose a heart attack or episode of sudden cardiac arrest to prevent death.