Congenital aortico-right atrial communications. The dilemma of differentiation from coronary-cameral fistula.

Four cases of an unusual form of aortico-right atrial communication are described. All patients were asymptomatic but had an atypical continuous murmur on examination. A distinctive appearance was noted on the angiograms, with a large tortuous tunnel noted superior to the left sinus of Valsalva, passing posterior to the aortic root before terminating near the right atrial-superior vena caval junction. This structure was readily identified by two-dimensional echocardiography. The defect was successfully closed surgically in three of four patients. The presence of normal major coronary arteries and absence of any small myocardial coronary branches from the tunnel argues against the structure being a coronary-cameral fistula and supports the diagnosis of aortico-right atrial tunnel.