The Big Squeeze

Spasm causes heart attack

Margaret, 32, a California housewife, seemed in perfect health. Then, while shopping one day, she suddenly fell to the floor dead, apparently of a heart attack. Harry's demise was less unexpected; the New York stockbroker, 49, had been suffering from angina pectoris, periodic attacks of severe chest pain, for several months before he died in his sleep. In both cases, doctors assumed the fatal attacks had been triggered by blood clots or atherosclerotic plaques clogging the pencil-thin arteries that supply oxygen-rich blood to heart muscle. But autopsies showed that the coronary arteries of both victims were free of obstruction.

What caused the attacks? A growing number of cardiac specialists now agree on the probable villain in these and thousands of other heart attacks: coronary artery spasm, a sudden and transient constriction of a blood vessel. Lasting from 30 seconds to many minutes, the spasm effectively blocks a vessel and keeps oxygen from reaching the heart.

The notion of coronary spasm dates back at least to the turn of the century. But there was no proof, and spasm remained simply a theory, overshadowed by mounting evidence that atherosclerotic disease was a major cause of cardiac attacks. Then, in 1970, doctors got "the first eyeball look at an episode of coronary spasm." At the University of California in Los Angeles, Cardiologist Albert Kattus and his team were doing a coronary bypass operation on a woman when suddenly one of the vessels began to constrict. As that happened, Kattus recalls, "we could feel that her coronary artery was tough like twine instead of soft and pliable."

Today spasm is one of the most active areas of medical research. Last week, in Anaheim, Calif., at a meeting of the American Heart Association, experts discussed the newest findings. Two of their more intriguing speculations:

> Coronary spasm may explain the infrequent incidents of chest pain and heart attack in premenopausal women, who rarely develop atherosclerosis. The spasm may cause blood to flow more slowly, thus allowing blood platelets to clump, clot and seal off the pathway.

> Spasm may be the underlying cause of angina, coronary attacks, and sudden unexplained death in cases where the heart arteries are partly clogged by fatty plaque buildup. Dr. Attilio Maseri reported that, while at the University of Pisa, he examined some 200 patients who suffered chest pains during periods of inactivity and who had varying degrees of atherosclerosis. He found that their chest pains were due to spasm. Said he: "Atherosclerotic narrowing of the vessels is the bystander rather than the culprit of angina in such patients." But, experts agree, a spasm that might merely hinder the flow of blood in a healthy artery could completely block it in one already partly narrowed by fatty deposits.

What causes the spasm is not yet clear, but there is anecdotal evidence that psychological stress plays a role. Researchers also know that clumping blood platelets release thromboxane A2, a substance that causes the constriction of blood vessels and therefore can trigger spasm.

The awareness about spasm has led to a new line of attack against heart disease. Traditional coronary dilators, like the nitroglycerin tablets taken by angina patients, may assume greater importance--as will new ones, such as the experimental drugs nifedipine and verapamil.

Doctors are also enthusiastic about a substance that inhibits the aggregation of platelets and may reduce the risk of spasm--that old standby called aspirin.

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