The ejection fraction provides a relative measure of the strength or weakness of the heart by indicating the amount of blood the heart squeezes out to the rest of the body with each beat. A normal ejection fraction is 55 to 60 percent, meaning that much of the total blood in the main pumping chamber is ejected with each beat. An ejection fraction below 50 percent indicates increased risk for congestive heart failure, the most rapidly growing form of heart disease in the country, said Dr. William Abraham, director of cardiovascular medicine at Ohio State’s Medical Center.
Given many Americans’ propensity to eat more than necessary, exercise less than is ideal and endure highly stressful professional and personal lives, “Most U.S. adults should know their ejection fraction,” Abraham said. More specifically, anyone with risk factors for developing weak hearts should also be aware of their ejection fraction. Those risk factors include high blood pressure, diabetes, high cholesterol, obesity, coronary artery disease, prior heart attack, heart valve abnormalities and a family history of heart failure.
“I think we should add ejection fraction to the list of numbers that are good to know about our own health,” Abraham said. “Taking measurements of blood pressure, cholesterol and blood sugar levels leads us to treat patients to reduce risks associated with those numbers. Similarly, knowing ejection fraction would help us identify and treat earlier those patients who are susceptible to heart failure.”
Ejection fraction can be determined through a noninvasive, painless echocardiogram, essentially an ultrasound of the heart.
Symptomatic congestive heart failure affects an estimated 5 million Americans. Of those, up to 1 million are classified as moderate to severe cases, experiencing shortness of breath, fatigue and palpitations that either limit or prevent patients from participating in physical activity. Heart failure is characterized by a reduced ejection fraction and sometimes leakage of fluid into the lungs, feet, legs or abdominal cavity.
But Abraham said another 20 million Americans are estimated to have a reduced ejection fraction that currently isn’t accompanied by any symptoms. “These are the people we would like to catch,” he said.
A low ejection fraction isn’t associated only with chronic illness. It also makes patients between six and nine times more susceptible to cardiac arrest or sudden cardiac death – the No. 1 cause of death in America – than patients with a normal ejection fraction.
A heart determined to be weaker than normal doesn’t have to stay that way. Abraham, also deputy director of the Davis Heart and Lung Research Institute at Ohio State, said that in the past 10 years, research has led to the availability of a host of medications and devices that can help unhealthy hearts. “Enlarged hearts can get smaller and weak hearts can get stronger again with proper drugs and, in some instances, device therapies,” he said.
The most common classes of drugs are ACE inhibitors, angiotensin receptor blockers, beta-blockers and aldosterone antagonists. Devices for patients with reduced ejection fraction are specialized pacemakers called cardiac resynchronization therapy devices, which coordinate the pumping action of both sides of the heart. Some CRT devices are combined with implantable cardioverter defibrillators, which can deliver a shock to stop cardiac arrest.
Abraham noted that lifestyle changes should never be counted out as methods to reduce risks for heart disease.
“To go to the very beginning of the spectrum, patients with risk factors such as high blood pressure, obesity and diabetes can avoid ever developing reduced ejection fraction if those risk factors are treated vigorously – through a combination of lifestyle changes and medications – in the first place,” he said.