Advances in heart care shrink death rate.

A decline in heart disease deaths since 1980, though gratifying, has confounded researchers, who find it difficult to reconcile with evidence that one in four people still smoke and many ignore other entreaties to protect their hearts.

Now, a study of coronary heart disease mortality between 1980 and 1990 shows that the death rate indeed dropped by 34 percent, say Milton C. Weinstein and his colleagues at the Harvard School of Public Health in Boston. Half of the decline resulted from treatment, including new clot-busting and cholesterol-lowering drugs, bypass surgery, artery-clearing angioplasty, and other advances.

Credit for the rest of the decline goes equally to two preventive strategies: avoiding heart disease in the first place by quitting smoking, losing weight, and lowering blood pressure and cholesterol, and reducing the risk of a second heart attack through changes in diet and lifestyle.

Taken together, improvements in treatment and prevention saved the lives of 127,000 people who would have died if the advance of coronary medicine had stopped in 1980. Of this number, the study showed, 70 percent were people who already had heart disease.

In an average year, heart attacks strike 700,000 people. Ten percent die within 24 hours, and many of the survivors face the future with a weakened heart. All told, coronary heart disease buries about 400,000 people in the United States each year, more than any other ailment.

Though bleak, these statistics nevertheless reflect a decline from heights reached in the 1960s, before health officials began publicly imploring people to guard against heart disease. Between 1970 and 1980, such efforts produced a 30 percent decline in mortality from the disease.

The death rate continued to decline through 1990, even though heart disease prevention campaigns had achieved what researchers thought would be their maximum impact. The persistence of the trend, says Thomas E. Kottke of the Mayo Clinic in Rochester, Minn., touched off a debate between the "primary, secondary, and treatment folks."

The primary prevention group linked the decline to continuing reductions in the risky behaviors that cause heart disease. Advocates of secondary prevention credited measures designed to reduce the risk of a second heart attack; the rest favored better medical care for those who already suffered from heart disease.

Weinstein and his colleagues set out to resolve this dispute. Their study, published in the Feb. 19 Journal of the American Medical Association, used a computer model to weigh factors that contributed to-or reduced-heart disease mortality among people age 35 to 84. These included heart attack rates, risk factors, and treatments.

The researchers adjusted the relative importance of all these variables until the computer model reproduced nationally tabulated death rates from coronary heart disease for 1980 and 1986. They could then use the model to generate an analysis of deaths averted through specific methods of prevention or treatment.

"We plugged in estimates of what actually occurred during the decade," Weinstein explained. The computer "played out different scenarios." Kottke cautioned against interpreting the study to mean that technology will eventually eliminate deaths from heart attack. "There's still a significant portion of the population dead within 24 hours of a heart attack. If you're betting that the technology will be there for you, you might also wonder whether you'll be there for it."