Ask the doctor: What is a myocardial bridge?

Ask the doctor

Q. After some recent heart tests, my doctor said everything looked fine. But the report he sent me mentions a myocardial bridge. Should I be concerned?

A. In this condition, which is usually thought to be harmless, a segment of one of the heart's main arteries tunnels into the heart muscle and back out again instead of resting on the surface of the heart. The bridge refers to the band of heart muscle (myocardium) that stretches over that section of the artery.

A myocardial bridge shows up in fewer than 5% of people who undergo a cardiac catheterization, in which a doctor snakes a thin, flexible tube into a large blood vessel leading to the heart. And heart imaging tests sometimes detect a myocardial bridge. But autopsy studies suggest that the condition may be common, with some prevalence reports above 30%.

Most people with this condition, which is generally present from birth, don't have any symptoms. But the segment of the blood vessel that dips into the heart muscle may be squeezed when the heart contracts, especially if the heart muscle is thickened. In rare cases, this causes symptoms similar to those of a heart attack, including chest pain, tightness or pressure in the chest, pain in the left arm or jaw, or shortness of breath. When that happens, doctors usually prescribe medications such as beta blockers and calcium-channel blockers.

— Deepak L. Bhatt, M.D., M.P.H.
Editor in Chief, Harvard Heart Letter