A rare localization of muscular bridge causing myocardial ischemia.

The coronary arteries are normally localized subepicardially and are visible on the surface of the heart. Myocardial bridge is a most common congenital abnormality of coronary arteries. A segment of coronary artery travelling trough myocardial tissue, which is called tunneled artery, exhibits compression during systole. Generally, it is a benign condition and often asymptomatic, but it may also be accompanied by chest pain, dyspnea, myocardial infarction, ventricular arrhythmias and/or sudden death. We report a rare localization of myocardial bridge in the right coronary artery, which caused myocardial ischemia. A 51-year-old male patient was admitted to our clinic with the complaint of chest pain on exertion for one month. His physical examination revealed blood pressure of 120/70 mmHg, pulse rate of 70 per minute and system examinations were normal. On the electrocardiogram, there was no abnormality. Transthoracic echocardiography revealed infero-posterior wall hypokinesia. Exercise stress testing was performed and it revealed horizontal ST segment depression of 1 to 2 mm in leads II, III, aVF and V5-6. Upon this, coronary angiography was done. Coronary angiography showed stenoses of the mid left anterior descending artery-30%, 1st diagonal artery-50%, distal circumflex artery 50%, and the typical ‘milking effect’ for myocardial bridge in right coronary artery (RCA), causing 70% stenosis at systole (Video 1. See corresponding video/movie images at www.anakarder.com). Ventriculography was normal. In our case, myocardial bridge was observed in RCA that has been reported in the literature rarely.