Relation between extent of left ventricular hypertrophy and occurrence of sudden cardiac death in hypertrophic cardiomyopathy.

Sudden unexpected death can be the first clinical manifestation of hypertrophic cardiomyopathy and is the most devastating feature of the natural history of the disease. Left ventricular hypertrophy appears to be an important determinant of many clinical features of hypertrophic cardiomyopathy, but the relation between its magnitude and the occurrence of sudden cardiac death has not been clearly defined. In this study, the magnitude of hypertrophy was assessed with two-dimensional echocardiography in 29 asymptomatic or mildly symptomatic patients with hypertrophic cardiomyopathy who subsequently died suddenly or experienced cardiac arrest with documented ventricular fibrillation. Findings were compared with those obtained in a control group of 95 patients of similar age and symptomatic state. Maximal left ventricular wall thickness was significantly greater in patients with sudden death (26 +/- 7 mm) than in control patients (21 +/- 5 mm, p less than 0.001). Left ventricular wall thickness index, a quantitative expression of the overall extent of hypertrophy, was also greater in patients with sudden death (76 +/- 20 mm) than in surviving control patients (62 +/- 13 mm, p less than 0.001). Particularly marked and diffuse hypertrophy, with maximal wall thickness greater than or equal to 30 mm or wall thickness greater than or equal to 25 mm in two or more of the four segments into which the left ventricle had been divided, was eight times more common in patients with sudden death (11 [38%] of 29) than in control patients (5 [5%] of 95, p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)