Although blacks are at least as likely as whites to get coronary artery disease, they undergo heart bypass surgery much less frequently, reports a Johns Hopkins heart surgeon.

Blacks, who make up 12 percent of the population, receive only about 2 percent of the bypass operations, says Dr. Levi Watkins Jr., associate professor of cardiac surgery at the Johns Hopkins University School of Medicine in Baltimore.

"One glaring thing that stares you in the face," he says, "is an extraordinary disproportion in utilization of the surgery."

Several factors contribute to the low rate of heart surgery in blacks, Watkins says, including the myth that heart disease is rare among black people. He also cited blacks' relatively poor access to health care, their lack of health insurance coverage because of high unemployment, and the tendency of some blacks to overlook or tolerate early symptoms of heart disease.

Heart disease is the leading cause of death in both black and white Americans. Heart attacks alone kill more than 550,000 a year, including 57,000 blacks.

Coronary bypass surgery, in which a section of healthy vein, usually from the leg, is grafted onto the aorta to bypass one or more disease-clogged coronary arteries, is one of the most frequently performed operations in the United States. But not among blacks, who are less likely than whites to be diagnosed promptly and referred for exploratory procedures such as coronary arteriography.

Watkins began looking into the issue four years ago, after he was questioned about it at a national medical convention and had to answer that he didn't know. After searching the medical literature in vain for published data comparing rates of heart surgery among blacks and whites, Watkins did his own survey and came up with the 2 percent figure.

"It embarrassed me a little as a physician, and it embarrassed people when I presented the findings at a conference earlier this year," he says. "There were some physicians who were shocked."

At Johns Hopkins, he found, only 56 blacks had bypass surgery between 1972 and 1980 -- an average of seven per year. During the same eight-year period, more than 2,500 whites underwent heart bypass surgery at Hopkins.

Moreover, in half of the black patients -- more than double the percentage of white patients -- heart disease had advanced far enough to cause severe unstable angina (chest pain), putting them at high risk of heart attack.

Since Watkins began gathering data, the number of blacks undergoing open-heart surgery at Johns Hopkins has risen steadily. This year, blacks are expected to account for about 10 percent of the heart bypass operations at Hopkins, he says.

"The bottom line," says Dr. Charles Curry, chief of the division of cardiovascular diseases at Howard University College of Medicine, "is that black people are undergoing fewer coronary artery bypass operations than you'd expect, when you take into consideration the incidence of coronary artery disease in black people."

A major reason, according to both Watkins and Curry, is the erroneous but widespread historical belief that black people are less likely to get heart disease. Black patients may tend to overlook symptoms of mild chest pain (attributing them to other causes, such as heartburn) and put off seeing a doctor.

"Poor people of all races have to be educated about angina and heart disease," Watkins says. "It just so happens that a much larger percentage of the black population is poor."

"They may not know the significance of chest pain and pain down the arm," he says. "And if they're struggling to make a living, unless it's incapacitating, they'll just keep on struggling to make a living."

"Then," Curry says, "when the patient finally gets to the doctor, the doctor may make the same mistake. It is underdiagnosed."

Although the myth that blacks don't get heart disease as often as whites has been corrected in most major medical centers, it persists even today, particularly among older doctors.

"If you don't think someone is going to have it heart disease , you won't find it," says Dr. Rosalyn Sterling, assistant professor of surgery at King-Drew Medical Center in Los Angeles.

"There are a lot of physicians who just don't think about heart disease in black people," she says. "We all know that's not true, but we've all been on panels where doctors say, 'We don't see heart disease in blacks.' "

As a result, Sterling says, diagnoses are delayed and heart surgeons operate on seriously ill patients "who should have been picked up years ago -- whose heart muscles have deteriorated."

Bypass surgery has come under increasing criticism recently for its alleged overuse. But Watkins notes that even if the operation were limited to patients with the most severe and painful type of coronary artery disease, blacks should account for a far higher share than 2 percent of the nearly 200,000 bypass operations done annually.

The black-white disparity in heart treatment is finally getting attention from doctors and researchers, who are studying racial patterns in the delivery of health care.

"Nobody's been interested until the past few years," says Dr. Richard Gillum, a cardiologist and researcher with the National Center for Health Statistics."

The American Heart Journal devoted an entire issue last September to the subject of coronary heart disease in black populations, including a report of the National Heart, Lung and Blood Institute.

That is all the more remarkable in view of some articles on heart disease Watkins discovered in the same journal's past.

"There are numerous comments in the literature on the rarity of angina pectoris in the negro," began an article by a University of Louisville doctor in the American Heart Journal in 1940. "Most clinicians in the southern part of the United States are in accord that it is infrequently encountered in this race."

The explanations given were unabashedly racist.

"A lack of ability to fully describe and interpret the sensation of cardiac pain can entirely explain the infrequency with which the syndrome is encountered in the negro," the article concluded.

Another American Heart Journal article from the same era, based on a speech at the 1938 meeting of the American Heart Association, described the incidence of angina this way:

"It occurs usually in the sensitive, nervous type, as the Jew, or in the tense, efficient American, rather than in the dull, happy negro or the calm, accepting Chinaman."

Out of 20,000 blacks hospitalized in Atlanta during a nine-year period, reported the author, an Atlanta physician, only five had been diagnosed as having angina. The author himself, during 20 years of practicing medicine, "never saw a case in a negro." He cited reports by seven other doctors, all of whom claimed that angina was either nonexistent or extremely rare among blacks.

Watkins won't excuse such statements, but says they must be considered "in the context of the times." They are important, he says, "because there may be some people out there who still don't think blacks get heart disease.

"I don't think the misconception today is a racist one. It's just misinformation."