Sudden death in the community.

About one fifth of all deaths occur suddenly and unexpectedly, often as the first manifestation of heart disease. Several tests have been developed during the past 2 decades for risk stratification of such an event, but only a minority of victims can be identified as being at high risk before sudden death occurs. Improving the results of out-of-hospital resuscitation attempts is of crucial importance. Use of the automated external defibrillator is rapidly increasing worldwide. However, the defibrillator must be used within minutes after the onset of cardiac arrest, and rapid recognition and localization of the victim are essential. The development of a device that constantly monitors vital signs and can diagnose cardiac arrest, generate an alarm, and transmit the location of the victim could be an important step in improving the results of cardiac resuscitation.