Severe Mitral Regurgitation Following Acute Myocardial Infarction and Ruptured Papillary Muscle

The results of operative treatment are described in four patients who sustained myocardial infarctions and in whom ruptured left ventricular papillary muscles caused severe mitral regurgitation. All were men between 51 and 69 years of age, and the intervals between myocardial infarction and operation were 3 to 15 months. Each patient manifested severe congestive heart failure. All were in sinus rhythm and had an apical holosystolic murmur and an atrial gallop sound. Three of the four had severe pulmonary hypertension (60 to 80 mm Hg systolic), grossly elevated mean left atrial pressure, and v waves 37 to 45 mm Hg. In all the cardiac index was abnormally low (average 1.8 L/min/m2). In all four patients the mitral valve was replaced with a 2M Starr-Edwards prosthesis. In two of the excised valves, one head of the posterior papillary muscle was infarcted and had ruptured, and in the other two the anterior papillary muscle was similarly involved. All patients survived, and all have derived distinct symptomatic improvement at intervals of 7 to 16 months. Hemodynamic studies were repeated 11 months postoperatively in one patient; although he is asymptomatic and the cardiac index is increased, intracardiac pressures remain elevated, and residual impairment of left ventricular function is evident. In a second patient the left ventricle apparently retained satisfactory functional capacity for symptomatic benefit has been paralleled by striking reductions in pulmonary arterial and left atrial pressures measured six months postoperatively.