Abstract
<title>Abstract</title> <p> <bold>Background</bold> Ventricular septal perforation is a rare but life-threatening mechanical complication of acute myocardial infarction that typically occurs within the first week after infarction. Delayed presentation after completed anterior myocardial infarction is uncommon, particularly in patients with concomitant left ventricular mural thrombus and ventricular aneurysm. We report a rare case of delayed ventricular septal perforation following completed anterior myocardial infarction despite surgical revascularization. <bold>Case presentation</bold> A 58-year-old Japanese man presented with progressive dyspnea and anorexia 9 days after symptom onset. Coronary angiography demonstrated total occlusion of the left anterior descending artery without collateral circulation and severe stenosis of the proximal right coronary artery. Emergency percutaneous coronary intervention under intra-aortic balloon pump support was unsuccessful, and emergency off-pump coronary artery bypass grafting using the left internal thoracic artery to the left anterior descending artery was performed. Intraoperatively, the anterior wall was already aneurysmal, and the left anterior descending artery showed severe fibrosis without distal back bleeding, indicating completed transmural infarction with poor distal runoff. One week after surgery, the bypass graft was found to be occluded, and transthoracic echocardiography revealed a 30 × 12 mm left ventricular mural thrombus within the apical aneurysm. Anticoagulation with heparin followed by warfarin resulted in gradual thrombus resolution. Four weeks after coronary artery bypass grafting, a new systolic murmur developed, and echocardiography demonstrated a 12 × 20 mm anteroapical ventricular septal perforation with a pulmonary-to-systemic flow ratio of 2.4. Semi-urgent surgical repair using a modified Daggett technique with a single Dacron patch was successfully performed. No residual shunt was detected postoperatively, and the patient was discharged in New York Heart Association functional class I. <bold>Conclusions</bold> This case demonstrates that patients with completed anterior myocardial infarction remain at risk for delayed mechanical complications despite surgical revascularization. Careful serial echocardiographic surveillance should be considered in patients with ventricular aneurysm and left ventricular mural thrombus, particularly when new cardiac murmurs develop or thrombus resolution is observed. </p>