Sudden cardiac arrest and automated external defibrillators.

major (approximately 66–94.5%) cause of sudden death worldwide.1–4 The remaining causes of sudden death are noncardiac conditions, including epilepsy, alcohol abuse, pulmonary embolism, trauma, cerebrovascular accidents and unknown etiology.5 The annual occurrence of sudden death is 350,000–450,000 in the United States, 10.5 per 100,000 population in United Kingdom and 37 per 100,000 in Japan. 6,7 In the United States, there were 341,780 reported cases of out of hospital sudden cardiac death in 1999, which accounted for 47% of all cardiacrelated deaths.7 Identifying the individual at risk for cardiac arrest remains difficult, and approximately 20% of people who suffer from SCA do not have any prior cardiac history. Despite an increase in public awareness and implementation of several programs to rescue individuals from SCA, as well as advances in preventive therapy, the proportion of out-of-hospital SCA has increased 23.5% over the past decade. 8