18. Which of the following is true regarding myocardial bridging of a coronary artery?

A. Myocardial bridging frequently causes stable anginal symptoms

B. Medical therapy with nitrates is effective

C. Myocardial bridging is considered a benign finding and does not commonly cause symptoms

D. Surgical excision of the intramyocardial coronary artery is often required

E. Patients with myocardial bridging should be on beta-blocker therapy since decreasing heart rate and contractility will improve coronary flow in this scenario

 

Myocardial bridging occurs when a coronary vessel does not run along the epicardial surface of the heart, but instead dives deeply to run within the myocardial wall itself. During contraction, the coronary vessel can be compressed and is frequently seen on angiography. Exercise exacerbates this due to increased contractility and faster heart rates resulting in decreased time in diastole (recall that the coronary arteries fill in diastole). Beta-blockers would in theory improve this situation, however since angina is rarely present, beta-blockers are not indicated for patients with myocardial bridging.

Only on rare occasions in severe cases is myocardial bridging thought to cause angina. A majority of time it is a benign finding and has no clinical significance. Vasospasm has been found to be more common in patients with myocardial bridging. Case reports of grafting a left internal mammary artery to relieve angina in symptomatic patients have been published, but no medical therapy is specifically indicated.