Sudden death in hypertrophic cardiomyopathy: a profile of 78 patients.

The clinical profile of 78 patients with hypertrophic cardiomyopathy who died suddenly (or experienced cardiac arrest and survived) was analyzed. At the time of cardiac catastrophe, 71% of the patients were younger than 30 years of age, 54% were without functional limitation and 61% were performing sedentary or minimal physical activity. Nineteen of the 78 patients (24%) were taking propranolol in apparently adequate dosages, indicating that this drug does not provide absolute protection against sudden death. No clinical or morphologic variable was particularly reliable in identifying patients at risk for sudden death. Forty-eight of 62 patients (77%) who died suddenly had a markedly increased ventricular septal thickness of 20 mm or more; however, mean septal thickness was similar in patients who died suddenly (25.2 +/- 0.9 mm) and in age- and sex-matched control patients with hypertrophic cardiomyopathy who have survived (23.6 +/- 0.8 mm). An abnormal ECG was present as often in patients who died suddenly as in control patients who have survived, (51 or 53, 96%). In addition, no particular cardiac symptom or hemodynamic variable (such as the magnitude of left ventricular outflow tract obstruction under basal conditions or left ventricular end-diastolic pressure) was characteristic of the patients with hypertrophic cardiomyopathy who died suddenly.