Definition of patients at high risk of sudden arrhythmic cardiac death.

Prevention of sudden arrhythmic cardiac death must be preceded by identification of the high-risk patient to whom appropriate therapy can be given. The most common disease state associated with sudden cardiac death is coronary artery disease. Factors which identify a high-risk subset include: left ventricular dysfunction; frequent and complex arrhythmias on Holter monitoring; abnormal signal-averaged electrocardiograms; angina, ST depression, and exertional hypotension or ventricular arrthythmias on exercise testing; inducible sustained arrhythmias at electrophysiologic testing, or a combination of these factors. Other conditions which are known to be associated with sudden death include: dilated or congestive cardiomyopathy, hypertrophic cardiomyopathy, mitral valve prolapse, valvular heart disease, Wolff-Parkinson-White syndrome, myocarditis, congenital heart disease, electrolyte abnormalities, long QT syndromes, proarrhythmic effects of drugs, and less common conditions such as myocardial tumors and pulmonary hypertension. If the primary abnormality responsible for the tendency toward arrhythmias cannot be corrected, appropriate therapy should be administered to attempt to reduce the patient's risk of sudden arrhythmic cardiac death.