Doppler echocardiographic study of the frequency and severity of aortic regurgitation in hypertrophic cardiomyopathy.

Aortic regurgitation (AR) has been reported sporadically in hypertrophic cardiomyopathy (HC) but neither its frequency nor severity has been determined. Thirty-one consecutive patients with HC were evaluated by Doppler echocardiography over a 2-year period. Twenty-nine had echocardiographically normal aortic cusps and participated in the study; 2 had calcified aortic valves and were excluded. AR of grade I to grade II severity was demonstrated in 9 of 29 (31%) patients. Patients were divided into 2 groups: group 1 (n = 9) with AR and group 2 (n = 20) without AR. Group 1 patients were significantly older than group 2 patients (73 +/- 7 vs 60 +/- 17 years, p less than 0.05) and had larger end-diastolic (4.5 +/- 0.5 vs 4.0 +/- 0.7 cm, p less than 0.01) and end-systolic (2.7 +/- 0.4 vs 2.3 +/- 0.4, p less than 0.02) left ventricular dimensions. Left ventricular wall thickness, degree of asymmetric septal hypertrophy and left ventricular fractional shortening were similar in the 2 groups. Mitral regurgitation was more common in group 1 (100% vs 35%, p less than 0.005), although there were no differences in left atrial size between the 2 groups. The HC patients were compared with a control group of 23 normal subjects of similar age. There was no mitral regurgitation or AR in the normal subjects. Thus, nearly one-third of patients with HC had mild AR by Doppler. The AR most probably results from high-velocity systolic blood flow causing microscopic damage to the valve cusps.