Absence of progression of left ventricular hypertrophy in adult patients with hypertrophic cardiomyopathy.

Development or progression of left ventricular hypertrophy has recently been described in children with hypertrophic cardiomyopathy. To determine whether similar changes in magnitude and distribution of left ventricular hypertrophy may also occur in adult patients with this disease, serial assessment of left ventricular wall thickness was obtained with M-mode and two-dimensional echocardiography in 65 patients with hypertrophic cardiomyopathy who were 23 to 50 years of age. The follow-up period was 3 to 6 years (mean 4). None of the 65 patients showed a substantial increase (greater than or equal to 5 mm) in left ventricular wall thickness; however, 9 (14%) demonstrated a substantial decrease (5 to 9 mm). Wall thinning most commonly involved the anterior ventricular septum (seven patients), but was also identified in the posterior septum (six patients), lateral free wall (two patients) and posterior free wall (one patient). In the nine patients with wall thinning, left ventricular end-diastolic diameter increased significantly (from 44 +/- 6 to 51 +/- 6 mm; p less than 0.001); however, in seven of the nine, absolute cavity size remained within normal limits (less than or equal to 52 mm) at the most recent evaluation. Eight of the nine patients with left ventricular wall thinning and relative cavity enlargement were severely symptomatic and one was mildly symptomatic. In conclusion, substantial progression of left ventricular hypertrophy was not identified in any of the study patients. Hence, if such progression occurs in adults with hypertrophic cardiomyopathy, it is probably rare. Conversely, an important minority of adult patients with hypertrophic cardiomyopathy may show progressive left ventricular wall thinning and relative cavity enlargement, which are usually associated with severe cardiac symptoms.