Progression of hypertrophic cardiomyopathy. A cross sectional echocardiographic study.

The progression of hypertrophy was studied in 39 patients with hypertrophic cardiomyopathy by echocardiography at follow up from January 1979 to September 1983 (mean follow up 42 months). Thirty two patients were treated medically and 11 had had a septal myotomy-myectomy. Progression of the hypertrophy was noted in four patients treated with propranolol. An additional region in the left ventricular long axis plane was affected in two, extending to the apical region in one and to the basal region in the other, and an additional segment in the left ventricular short axis plane in two extending from the septum into the free wall. The electrocardiograms of these four patients showed a significant increase in QRS voltages (Sokolow-Lyon index increase greater than 10 mm) and of the Romhilt-Estes score (increase greater than or equal to 3 points) in two, development of a left bundle branch block in one, and no change in one. Progression of hypertrophy was seen in none of the 11 patients treated with myotomy-myectomy. Thus echocardiography accurately detects the progression of hypertrophy in patients with hypertrophic cardiomyopathy, which may be prevented by septal myotomy-myectomy.