Left ventricular free wall rupture is a complication following acute myocardial infarction or mitral valve replacement. We report the case of a 56-year-old female patient with idiopathic left ventricular rupture confirmed by contrast-enhanced computed tomography (CT). CT also showed no coronary artery obstruction and severe mitral annular calcification. Left ventricular rupture was successfully repaired internally with bovine pericardium. Mitral valve replacement with annular decalcification was also performed.