A group of cardiologists has launched a campaign to encourage people at risk for heart disease to learn their ejection fraction, or “EF” - a measure of the heart’s blood-pumping power - to reduce their risk of sudden cardiac death.

Each year, 450,000 Americans die as a result of sudden cardiac death, which occurs when a person’s heart abruptly stops functioning. It often occurs in apparently healthy persons free of symptoms of heart trouble.

“People who have low EFs are prone to sudden cardiac death and there are certain therapies that can reduce that risk. That’s the reason for the campaign,” said Dr. Thomas Ryan, director of the Duke Heart Center in Durham, North Carolina and vice president of the American Society Echocardiography.

Doctors often use echocardiography, an ultrasound test of the heart, to measure EF. It’s a painless, noninvasive procedure that can be performed in a doctor’s office in under an hour, Ryan noted.

A normal EF is 50 percent or higher. An EF of 35 percent or less indicates a weakened heart muscle and increases the risk of irregular heart rhythms that can lead to sudden cardiac death. Other diagnostic symptoms include a history of shortness of breath, rapid heartbeat, dizziness or fainting.

“People with low EFs are at risk for a variety of very serious heart problems and some of these people might not know that their EF is reduced, although most people with a low EF don’t feel fine,” Ryan said. “But it certainly happens that patients (may have) no symptoms or at least nothing they attribute to heart problems and then they are found to have a low EF.”

The people who should consider having their EF measured, according to Ryan, are those with known heart disease or people who are at risk for developing heart disease such as those with multiple risk factors including high blood pressure, diabetes, cigarette smoking, family history, or people who have already had a heart attack or angina (chest pain).

“We are not recommending that everyone get their EF checked,” Ryan emphasized, noting “its important to check with your doctor and let your doctor help decide if that is appropriate.”