Sudden cardiac death, called SCD, is death caused by an abrupt loss of heart function. SCD occurs quickly and unexpectedly. Death results immediately or shortly after symptoms occur.
According to the American Heart Association, SCD causes 225,000 deaths in the United States each year. About half of all deaths from coronary heart disease are sudden and unexpected.
SCD may occur in people who have or have not been diagnosed with heart disease. However, underlying heart disease is almost always found in people who die of SCD. In fact, 9 out of every 10 people who die of SCD have narrowing caused by atherosclerosis in two or more of the three major coronary arteries.
Heart muscle scar tissue from previous heart attacks is present in two out of every three people who die from SCD.