A study of more than 46,000 Northern California Kaiser Permanente patients found a significant drop in heart attacks over a 10-year period, and more importantly, a major decrease in the most serious type of heart attacks - results that show that communitywide efforts to help people reduce their risk of heart disease seem to be working, doctors say.

The study, published in today's issue of the New England Journal of Medicine, showed that the heart attack rate among Kaiser patients fell 24 percent between 1999 and 2008 - the rate increased from 1999 to 2000, but declined every year after that. The types of heart attacks that do the most damage - known as ST-segment elevation heart attacks - fell 62 percent.

Over the same time period, more Kaiser patients lowered their blood pressure and cholesterol levels, and smoking rates decreased. The use of medications like beta-blockers and aspirin that are known to prevent heart disease increased. It would seem, authors of the study noted, that these preventive measures are working, perhaps even better than expected.

"Researchers keep trying to find more ways to treat heart attacks, but we need to focus just as much attention on things that we know work now, and doing those things on a large scale: adopting healthier lifestyles, stopping smoking, taking medications," said Dr. Alan Go, an author of the study and director of the Comprehensive Clinical Research Unit at the Kaiser Permanente Division of Research in Oakland.

A diverse study

Heart attack rates have been falling for more than 20 years in the United States with vastly improved preventive care and an understanding of the risk factors that lead to heart disease. But very few studies have looked at heart attack rates over the past 10 years, and the Kaiser study is one of the largest and most diverse in terms of age, race and sex.

The drop in heart attack rates is especially noteworthy, researchers said, because technology introduced in the last decade actually makes it easier for doctors to identify smaller, less serious heart attacks that may have gone undetected before. So even as doctors were able to catch more heart attacks, the rate continued to decline.

"If anything, the study underestimates the tremendous improvements that have been made to date," said Dr. Robert Pearl, executive director and CEO of the Permanente Medical Group.

In addition to the decrease in heart attack rates, the short-term death rate for heart attack victims improved. About 10.5 percent of patients who suffered a heart attack in 1999 died within a month, compared with 7.8 percent in 2008.

Looking at all heart attacks, the percentage of patients with the most serious types fell from 47 percent in 1999 to 23 percent in 2008. Part of that shift was due to doctors' ability to detect more of the less severe heart attacks, but part was due to a decline in the most severe heart attacks.

The more severe ST-segment elevation heart attacks - the name refers to a section of the waves produced by an electrocardiogram - occur when plaque builds up and ruptures, leading to a thick clot forming in a major artery and blocking blood supply. People with these heart attacks must have surgery immediately to unblock the artery.

In non-ST-segment elevation heart attacks, a less stable clot forms and blood is still able to move through the artery, although slowly. These patients can be treated with drugs that break up clots and thin the blood.

A wake-up call

These smaller heart attacks are, in a way, wake-up calls to patients that they need to make serious changes to prevent a more severe heart attack in the near future, said Dr. Michael Crawford, chief of clinical cardiology at UCSF Medical Center.

He said he wasn't surprised to see the overall drop in heart attack rates, but he didn't expect to see the rate of very serious heart attacks decline so much.

"That was really good news, because it suggests that the prevention things we're doing are really working, especially in terms of these events that really kill people," Crawford said. "It's hard for people to see on a personal level what preventative therapies are doing for them. By looking at the population, this really demonstrates that we're actually making headway."

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