Mid systolic closure of aortic valve in hypertrophic cardiomyopathy. Echocardiographic and angiographic correlation

To compare the reliability of the mid systolic closure of the aortic valve with asymmetric septal hypertrophy and systolic anterior motion of the mitral valve in predicting left ventricular outflow obstruction in hypertrophic cardiomyopathy, 15 patients with this clinical diagnosis and echocardiographic findings of asymmetric septal hypertrophy and systolic anterior motion of the mitral valve were studied. Of these, six (40 percent) had mid systolic closure of the aortic valve. All six patients had evidence of an intraventricular pressure gradient and angiographic findings confirming the presence of left ventricular outflow obstruction. Of the nine remaining patients, six (67 percent) had an intraventricular pressure gradient, whereas three (33 percent) had no demonstrable gradient. Of the six patients with a gradient and no mid systolic valve closure, only two had definite angiographic evidence of outflow obstruction; in the remaining four patients the gradient could be accounted for by the finding of left ventricular cavity obliteration. Among the total group of 15 patients, angiographic evidence of outflow obstruction was found in 8 (53 percent), whereas 7 (47 percent) had left ventricular cavity obliteration; these included the 3 patients with no intraventricular gradient. Of the eight patients with angiographic evidence of outflow obstruction, six (75 percent) had the echocardiographic finding of mid systolic closure of the aortic valve. Thus, although the incidence of mid systolic closure of the aortic valve in hypertrophic cardiomyopathy is relatively low, this finding appears to be a moderately sensitive sign of left ventricular outflow obstruction and may be a more specific predictor of outflow obstruction than asymmetric septal hypertrophy and systolic anterior motion of the mitral valve.