Giant Left Circumflex Coronary Artery Aneurysm With Arteriovenous Fistula to the Coronary Sinus

An 80-year-old woman with a history of breast cancer status post radiation therapy, paroxysmal atrial fibrillation, and congestive heart failure was referred to our institution for evaluation of a giant left circumflex (LCx) coronary artery aneurysm with fistulous communication to the coronary sinus. The patient initially presented with shortness of breath and non-ST elevation myocardial infarction associated with anterolateral T-wave inversion on ECG (Figure 1). Chest radiography showed a dense structure with a circular silhouette at the projection of the superior right mediastinum at the location of the right atrium in the posterior-anterior view and in the posterior mediastinum in the lateral view (Figure 2). She underwent cardiac catheterization, which showed no significant obstructive epicardial coronary artery disease. However, the angiogram revealed a large LCx coronary artery aneurysm with fistulous communication to the coronary sinus (Figure 3A and 3B; online-only Data Supplement Movies I and II). To better define the anatomic relationship of this aneurysm, a contrast-enhanced 64-slice multidetector computed tomography (MDCT) was performed. The location of the aneurysm was noted to be posterior to the left ventricle in juxtaposition with the left atrium, and its size measured 6.0 cm × 5.6 cm …