Coronary artery muscle bridging causing class III angina in a patient with no coronary atherosclerosis.

The significance of coronary artery muscle bridging (MB) has been debated since its first angiographic description by Portsmann and colleagues in 1960 (1). The course is usually benign; however, angina, myocardial infarction, sudden death, arrhythmias, and complete heart block have been reported. In this article, we present a case of coronary artery muscle bridging which caused a patient with no angiographic evidence of atherosclerosis to experience Class III angina.