Testing electrical activity of the heart using an electrocardiogram is unlikely to help doctors figure out who is at risk of coronary heart disease, according to recommendations from a U.S. government-backed panel.

The United States Preventive Services Task Force wrote on Monday that there's no good evidence the test, also known as an ECG, helps doctors predict heart risks any better than traditional considerations such as smoking, blood pressure and cholesterol levels in people with no symptoms.

"It could potentially be helpful if we had evidence that doing a test like an ECG or an exercise ECG would better classify the people who are at high risk" of heart disease, said Joy Melnikow, a member of the task force from the University of California, Davis.

"Then we could intervene more actively with the very high-risk group which has the highest potential to benefit."

The task force, which published a statement in the Annals of Internal Medicine, recommends against ECG screening of people considered at low risk for heart disease and says there's not enough information to rule one way or the other on those at intermediate or high risk.

On the other hand, there are both costs and possible harms associated with screening healthy adults, Melnikow said.

"The concern is that if people are already at low risk of heart disease and they have one of those tests, if they have an abnormality on the test it's more likely it will be a false-positive result," she added.

"But an abnormal result, whether a false positive or true positive, generally leads to additional testing, and it's the additional tests that could have some risk."

While ECGs themselves are inexpensive and non-invasive, the follow-up tests can involve passing a tube through the heart or other more intensive, costly procedures.

The new recommendations are an update of the USPSTF's 2004 guidelines, which also called for no screening in low-risk adults and said there was insufficient evidence to assess the risks and benefits for screening intermediate- and high-risk people.

Melnikow said that instead of asking for tests, people concerned about their heart health can discuss diet, lifestyle and family history risks with their doctor, who can then use a risk calculator to determine their chance of getting heart disease - and treat them appropriately.

"Everyone can benefit from being physically active," she said. "Everyone can benefit from not smoking, and people can discuss with their doctors whether they could benefit from taking medication to lower their blood pressure or lower their cholesterol."