Patients with hypertrophic cardiomyopathy have an increased risk for sudden cardiac death. The risk is equally high for patients with both the obstructive and nonobstructive forms of the disease. We have designed a multifaceted approach towards elucidating the etiology of sudden cardiac death which involves electrophyiolgic study in the cardiac catheterization laboratory to evaluate the likelihood of malignant ventricular arrhythmias; randomized study of conventional antiarrhythmic drugs and an investigational antiarrhythmic agent, amiodarone; and noninvasive studies such as 2-dimensional echocardiography and multiple surface electrocardigraphic leads to identify patients who might be at high risk for sudden cardiac death.