Unusual intra-arterial communication in the normal right coronary tree.

Among 136 patients with a history of angina pectoris who underwent selective coronary arteriography, two patients (1.4%) with a normal right coronary artery were found to have angiographically demonstrated communications between the various branches of the same coronary artery. Such findings, unaccompanied by coronary artery disease, have been hitherto unknown and suggest a congenital variation in coronary anatomy rather than a clinically significant condition. The purpose of this report is to demonstrate that the angiographic appearance of the anastomotic vessels in such cases is entirely different from that which obtains in cases of obstructive coronary artery disease. The author notes the rarity of angiographic visualization of homocoronary communications in normal right coronary arteries and emphasizes the necessity of distinguishing these from the homocoronary collaterals found in atherosclerotic coronary artery disease.