Unidirectional communication between the circumflex and right coronary arteries: a very rare coronary anomaly and cause of ischemia.

Intercoronary communication is an exceptionally rare congenital malformation. A 43-year-old male was admitted to our cardiology department with symptomatic stable angina. ECG and echocardiography was normal. Exercise electrocardiography showed ST depression in inferior leads. No atherosclerotic plaque in the coronary arteries was detected on coronary angiography. However, a unidirectional intercoronary communication between the circumflex and right coronary arteries, which was leading a coronary steal from right to left, was observed. Although intercoronary communication is generally not related with ischemia, ischemic symptoms and exercise ECG changes of this case suggested that unidirectional flow might cause myocardial ischemia via coronary steal. Consequently, intercoronary communication, a very rare coronary anomaly and a cause of ischemia, is discussed in this case report.