Of course, paying attention to your heart is a good thing. Everyone should have their blood pressure and weight measured at each doctor visit. Many should undergo basic tests such as those for high blood sugar and cholesterol. And knowing heart facts, like the signs of a heart attack, can be lifesaving.

But our online survey of 8,056 readers ages 40 to 60 found that many people overestimate their risk of heart attack. For example, 29 percent of the people with no history of heart disease and normal blood pressure and cholesterol levels described themselves as being at risk of heart disease, though only 9 percent said they had actually heard that from a doctor.

Many people also overestimate the ability of screening tests to provide reassurance. Healthy respondents whose recent tests included an electrocardiogram (EKG) were more likely than those who didn't to agree with the statement "going through the testing process is worth the peace of mind that comes with knowing everything is OK."

But the heart facts are that the test can produce falsely positive results in people without symptoms who are at low risk for heart disease. Almost no one recognized that potential harm: 87 percent completely or somewhat agreed that it was "better to have a scare that turns out to be nothing than to not get tested at all."

Truth is, the best things for your heart often aren't fancy tests or aggressive treatment. "People tend to view heart doctors as some sort of action hero and think the more aggressive, the better," says William Boden, M.D., a professor of medicine at the University at Buffalo Schools of Medicine and Public Health in New York. "But a conservative approach should never be considered passive or inferior."

The push to overtest and overtreat heart disease stems at least in part from outdated notions of it as a kind of plumbing problem. Doctors would often test for blockages and then clear them using angioplasty.

In that procedure, also called percutaneous coronary intervention (PCI), the doctor inflates a thin balloon in the narrowed artery to crush deposits, typically leaving a cylindrical insert called a stent in place to prop the vessel open. When performed within hours of a heart attack to clear a blocked or nearly blocked artery, the procedure works very much like clearing a clogged pipe. In those situations, it can be a lifesaving treatment.

But in nonemergency situations, the analogy breaks down. As it turns out, diseased arteries are riddled with smaller deposits that are the real troublemakers. We now know that most heart attacks occur not because a large deposit blocks an artery but when a smaller, less stable one ruptures, producing a blood clot that cuts off oxygen to the heart.

The latest research shows that drug therapy and lifestyle changes are the best first-line treatment because they address the underlying risk factors that cause deposits to form and trigger attacks. While angioplasty can help relieve symptoms such as chest pain or shortness of breath in people with stable disease, it doesn't prevent heart attacks or prolong life better than medical therapy alone.

Moreover, angioplasty triggers heart attacks in 1 to 2 percent of patients and adds thousands of dollars to the cost of treatment.

Furthermore, there's no need to scan people willy-nilly, because most people have some deposits in their arteries by the time they reach middle age. "I'm sure I have some arterial buildup," Lovett says. "It's just a process of aging."