Nonobstructive hypertrophic cardiomyopathy mimicking mitral stenosis. Documentation by echocardiography, phonocardiography and intracardiac pressure and sound recordings.

The physical findings in hypertrophic cardiomyopathy with left ventricular outflow tract obstruction are well described. In the absence of outflow tract obstruction the findings are less distinctive. There have been several reported cases in which the cardiac findings have suggested the diagnosis of mitral stenosis, In this report we describe a patient whose auscultatory and roentgenographic findings more closely mimicked mitral stenosis. The patient had a loud first heart sound, mitral opening snap and an apical presystolic murmur; left atrial enlargement was present. Noninvasive studies, including phonocardiography, echocardiography and apex cardiography, strongly suggested the correct diagnosis of nonobstructive hypertrophic cardiomyopathy. The diagnosis and unusual auscultatory findings were confirmed by results of cardiac catheterization and intracardiac phonocardiography. The importance of recognizing this syndrome and the use of noninvasive methods to establish the diagnosis are stressed.