A large coronary arteriovenous fistula with MRI and angiographic images.

DESCRIPTION A 71-year-old man was admitted with a 2-day history of intermittent palpitations. His initial ECG demonstrated a supraventricular tachycardia with a heart rate of 170 bpm. Following treatment with verapamil he reverted to sinus rhythm. As part of his initial investigations he had a two dimensional transthoracic echocardiogram. The parasternal long axis view demonstrated a well-circumscribed echo-free area in the left atrioventricular groove. Colour Doppler revealed blood flow within the lumen of the structure. The appearances were suggestive of aneurysmal dilatation of the left circumflex coronary artery. Selective coronary angiography revealed a large aneurysmal circumflex artery originating from a dilated proximal left coronary artery. The dilated tortuous loops of the circumflex artery coursed along the left atrioventricular groove and appeared to drain directly into a dilated coronary sinus (figure 1). The findings were suggestive of a fistulous communication between the left circumflex artery and the coronary sinus. The left anterior descending artery was not well visualised and the right coronary artery appeared normal. A subsequent cardiac MRI scan confirmed the presence of an arteriovenous fistula originating from the left coronary artery, which drained into amarkedly enlarged, aneurysmal