Cardiac Magnetic Resonance Imaging of a Coronary Sinus Diverticulum Associated With Congenital Heart Disease

A 6-month-old girl was referred for surgical repair of tetralogy of Fallot. A transthoracic echocardiogram revealed a large, unrestrictive ventricular septal defect, mild aortic override, a normal pulmonary valve with mild infundibular obstruction (peak gradient 22 mm Hg), a small patent ductus arteriosus, secundum atrial septal defect, and persistence of the left superior vena cava to the coronary sinus. The preoperative ECG showed sinus rhythm, mean frontal plane axis of 130°, right ventricular hypertrophy, and no signs of preexcitation (Figure 1). A chest x-ray showed cardiomegaly and prominent pulmonary vascularity with mild hyperinflation (Figure 2). Under cardiopulmonary bypass, the patient underwent repair consisting of resection of multiple infundibular muscle bundles, patch closure of the ventricular septal defect, suture closure of atrial septal defect, and ligation of the patent ductus arteriosus. She had an uncomplicated recovery, but a routine postoperative echocardiogram before discharge showed an echolucent mass measuring 16×22 mm, posterior and inferior to the …