Congenital aneurysm of the left main coronary artery with fistulous communication to the right atrium and coronary 'steal' phenomenon.

We describe a unique case of a left coronary arteriovenous fistula arising from an extremely short and aneurysmal left main coronary artery and selectively affecting the blood flow in the circumflex coronary artery. The relevant diagnostic contributions of two-dimensional echocardiography, colour flow Doppler, cardiolite stress testing and coronary angiography are discussed. The haemodynamic features of this anomaly are reviewed.