The coronary arteries are the blood vessels that supply blood to the heart muscle. Sometimes one of them can go into spasm. This is also sometimes called a vasospasm (VAS'o-SPAZ'm). This can reduce or even stop the blood flow to a part of the heart.

Spasm can occur in a normal coronary artery or in one that's partly blocked by fatty buildups (atherosclerosis) (ath"er-o-skleh-RO'sis). Why spasms occur isn't clear.

What problems does it cause?

When a spasm occurs, the person can have chest pain or discomfort called angina pectoris (AN'jih-nah or an-JI'nah PEK'tor-is). Spasms typically occur during rest rather than during exertion. If a spasm is severe, a heart attack is possible.

Calcium channel blockers are one class of drugs that may be used in people who have coronary artery spasm.

Related AHA publications:

• Understanding Angina