[Causes and importance of mitral valve insufficiency in the surgical treatment of hypertrophic obstructive cardiomyopathy].

In hypertrophic obstructive cardiomyopathy (HOCM) mitral incompetence is a frequent additional lesion. Echocardiography shows a SAM-phenomenon and the mitral suspension apparatus is transponed. In such cases myoectomy at typical spots alone or in combination with removal of the hypertrophied myocardium on the posterior wall of the left ventricle can influence the outflow tract positively. From 1963 to 1985 183 patients were operated with such lesions, 119 of them had preoperative mitral insufficiency of different degrees. In 9 patients mitral valve replacement was necessary. Hospital mortality was high in cases with mitral valve replacement. The decision whether the valve has to be replaced can be made after myocardectomy during the operation, but it should be done immediately, if mitral insufficiency persists.