A 59-year-old man was admitted to our hospital because of multiple traumas in a motorcycle accident. On admission, his vital signs were stable, however, 4 h later his respiratory condition suddenly worsened and be needed ventilatory support. Cardiogenic shock was suspected, however, the conventional echocardiograph findings were indistinct because of the presence of subcutaneous air. On the third day of hospitalization day, the Swan-Ganz catheter revealed high pulmonary arterial pressure. The subsequently performed trans-esophageal echocardiography showed severe mitral regurgitation. Therefore, semi-emergency mitral valve replacement was planned on the 5th hospital day. Operative findings showed that the anterolateral papillary muscle had torn off from the left ventricular wall and the associated strut chordae was also torn from the anterior leaflet. The post-operative course was uneventful, and the patient was discharged on the 40th postoperative day.