ABSTRACT
A 64-year-old man was transferred to our hospital because of acute heart failure associated with myocardial infarction. Echocardiography revealed severe mitral regurgitation due to total rupture of the posterior papillary muscle. Following the diagnosis of papillary muscle rupture, intraaortic balloon pumping support was started, and surgery was performed without coronary angiography because of cardiogenic shock and renal dysfunction. The posterior papillary muscle was completely ruptured, and the anterior leaflet of the mitral valve was severely prolapsed. Without resecting the posterior leaflet, mitral valve replacement was successfully performed using a St. Jude Medical<sup>®</sup> prosthetic valve. The postoperative course was uneventful except for ventricular tachyarrhythmia which occurred during the acute phase postoperatively. Postoperative coronary angiography demonstrated no significant coronary arterial stenosis. In a patient with cardiogenic shock due to papillary muscle rupture, immediate surgical intervention is recommended as soon as the diagnosis has been established by echocardiography.