Left ventricular pseudoaneurysm is an uncommon complication after transmural acute myocardial infarction (AMI). Here we describe the case of a 43-year-old man who presented with AMI and chest distress despite the normal appearance of his coronary artery during coronary angiography. Timely thrombolytic therapy was administered. Echocardiography, and cardiac computed tomography showed a ventricular pseudoaneurysm, and direct visualization at the time of surgery showed that it had ruptured in the mediastinum instead of the pericardium. The survival rate of patients with ventricular pseudoaneurysm rupture is low. The rupture of ventricular pseudoaneurysm in the mediastinum is rare; therefore, this case is noteworthy.