Abstract
A 47-year-old man presented with an inferior wall ST-segment elevation myocardial infarction (MI) and underwent a percutaneous coronary intervention with a drug-eluting stent in the mid-right coronary artery. Two days later, an echocardiogram revealed an unusual finding in the right ventricle (RV), resembling a second ventricular chamber. Further testing confirmed a left ventricular inferior wall pseudoaneurysm dissecting into the posterolateral wall of the RV and rupturing into the RV cavity, causing a left-to-right shunt that resembled a ventricular septal defect. He underwent a successful repair of the defects. This case demonstrates that acute mechanical complications after MI can be presented in a bimodal pattern, either early within 1-2 days or later around 5 days post-MI, highlighting the importance of careful echocardiogram interpretation.