Myocardial bridging in a patient with exertional chest pain

A 37-year-old man reported exertional chest pain. He smoked for years but had no other risk factors for coronary artery disease. Myocardial perfusion tomography showed a reversible lesion in the anterior and the apical inferior wall of the left ventricle. On cardiac catheterization, coronary arteries were normal during diastolic frames, but the midportion of the left anterior descending coronary artery showed a high-grade stenosis during systole. This "milking effect" and "stepdown-stepup" phenomenon is typical of myocardial bridging, produced by systolic compression of an epicardial coronary artery that has an abnormal intramural course. Beta-blockers are the first-line therapy in myocardial bridging because of their negative inotropic effect (reduced compression of the tunneled segment of the coronary artery) and negative chronotropic effect (longer diastolic period and consequently greater diastolic blood flow), whereas surgical myotomy and stenting are alternative treatment strategies for cases not responding to medical treatment. The patient was treated with a beta-blocker using 100 mg/day metoprolol, and angina was no longer present. Repeat stress myocardial imaging was normal. Copyright © 2005 by Lippincott Williams & Wilkins.