Arteriovenous fistulas of the circumflex and right coronary arteries with drainage into an aneurysmal coronary sinus.

The images presented here are from a 44-year-old asymptomatic man. At age 36 years, he experienced nonsustained atrial fibrillation. A year later, a transthoracic echocardiogram disclosed an enlarged left ventricle (diastolic dimension, 7.4 cm; ejection fraction, 56%) and a very large coronary sinus with Doppler color flow evidence of diastolic and systolic turbulence consistent with entry of a coronary arteriovenous fistula. Current selective coronary angiography visualized dilated circumflex and right coronary arteries, both of which entered an aneurysmal coronary sinus. An MRI during breath-hold acquisition further delineated the enlarged coronary sinus into which the circumflex and right coronary arteries drained (Figure 1). A 3-dimensional (3D) image set was then obtained by sequential MRI acquisitions during repeated breath-holding with surface reconstructions (Figure 2). The diameter of the proximal right coronary artery was 10 mm, and the diameter of the left main coronary artery was 11 mm (Figure 2, left). The circumflex artery was 11 mm in its proximal diameter, then abruptly widened to 18 to 20 mm and became very tortuous (Figure 2, left). The left anterior descending artery, by contrast, was 5 to 6 mm in diameter. The enlarged coronary sinus measured 8.534.533.5 cm (Figure 2, right) and compressed the inferior portion of the left atrium. These images assisted in planning surgical closure of the coronary arteriovenous fistulas, at which time the right atrial appendage with a portion of the enlarged right atrium was excised and a maze procedure was performed. Two months after operation, the left ventricular diastolic dimension was 6.1 cm and the ejection fraction was 45%. Six months after operation, the left ventricular diastolic dimension was 5.4 cm and the ejection fraction was 63%. An exercise radionuclide myocardial perfusion scan was normal. Only 5% of coronary arteriovenous fistulas arise from both right and left coronary arteries, and only 7% drain into the coronary sinus.1 Our patient is uncommon if not rare on both counts.