Prediction and prevention of sudden cardiac death.

The most common cause of SCD is coronary heart disease. Epidemiologic and pathologic studies have demonstrated the presence of chronic myocardial damage and extensive multivessel coronary disease as the substrate for SCD in ASHD. Instantaneous coronary death is an electrical event and not the result of acute coronary thrombosis. Patients resuscitated from out-of-hospital cardiac arrest who do not evolve acute myocardial infarction are at a greater risk of subsequent SCD than are infarctive patients. In studies of the posthospital phase of myocardial infarction, there are no predictive clinical variables that distinguish between sudden and non-sudden cardiac death. Current investigations suggest that activation of the sympathetic nervous system and the neurogenic release of catecholamines are important triggering factors in the genesis of arrhythmic SCD. Reduction in the occurrence of SCD will require community (mobile resuscitation units), public health (control of primary risk factors), and physician-initiated (anti-arrhythmic therapy) measures.