Endomyocardial biopsy (EMB) continues to remain the gold standard for surveillance of rejection post orthotropic heart transplantation (OHT). It can be performed under fluoroscopic or echocardiographic guidance. In the hands of an experienced operator, the complications of EMB are uncommon with <1% chance of any serious acute complications. Most common complications of EMB include access site-related complications, namely, venous thrombosis, carotid cannulation, hematoma, air embolism, and pneumothorax. We present a case of a rare complication of EMB in a patient with OHT causing a coronary sinus to right coronary artery (RCA) fistula.