Abstract
Coronary aneurysm is a vascular anomaly which can cause hemodynamic problems due to coronary steal phenomenon. We report the case of an asymptomatic 68-year-old woman with a large coronary aneurysm with fistula arising from the left main coronary artery. As a consequence of the longstanding volume overload, the coronary arteries were extremely dilated and drained through the coronary sinus into the right atrium.