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Puzzled? Confused? Or just plain curious?
A panel of leading medical experts tackles your questions.
Q My Ejection Fraction (EF) is just 10 to 15 percent, which is very low. But I still work full time, can walk a mile, and can do anything short of strenuous exercise. How come?
A Ejection fraction is the percent of blood pumped (or ejected) from either the right or left ventricle (lower chamber) during a single heart beat. A normal resting ejection fraction is 50 percent to 55 percent. EF can decrease if the heart is damaged by viral illness or a heart attack.
Exercise capacity is determined by how vigorously the heart contracts, and how efficiently skeletal muscles extract oxygen from the bloodstream. Thus, resting EF does not directly predict the heart's ability to increase pumping function during short periods of aerobic exercise.
G. William Dec, M.D.
Chief, Cardiology Division, Massachusetts General Hospital, Boston
Q I'm 59 and would like to run a few more marathons before hanging up my running shoes. I need an aortic valve replacement. What is the expected useful life of a tissue valve? With a mechanical valve I would be on warfarin (Coumadin™) for life, and am concerned about internal bleeding around the joints from the impact of running.
A There is no right or wrong answer in choosing an artificial valve. That said, a tissue valve typically needs replacement after 15 to 20 years, but the wear-and-tear associated with vigorous physical training could decrease its durability. In general, surgeons and cardiologists recommend mechanical valves for patients in your age group to avoid another replacement operation down the road. You needn't worry that warfarin will interfere with normal activities — including jogging and running. Weekly self-testing at home to check that blood levels of the anti-clotting agent are within therapeutic levels can help doctors manage potential bleeding complications.
Hartzell V. Schaff, M.D., F.A.H.A.
Division Chair, Cardiovascular Surgery, Mayo Clinic, Rochester, MN
Q I am a 51 year-old woman whose mother had heart problems. My doctor put me on atorvastatin (Lipitor™) as a preventative measure, though my cholesterol is normal. What are the pros and cons of taking atorvastatin long term?
A Family history may increase your own risk of developing coronary heart disease or hardening of other arteries in your body, and studies suggest that atorvastatin and other statins have a protective effect — even in people with normal cholesterol levels. Years of research and clinical experience have shown that statins are generally safe and well-tolerated. Your doctor will monitor liver function with regular blood tests, and will ask you to report muscle aches that could signal kidney damage. Given your family history, it's best you talk to your doctor about the risks and benefits of starting statin therapy, and whether it's a better option at your age than lowering your risk of heart attack and stroke through diet and exercise.
Lori Mosca, M.D., Ph.D, F.A.H.A.
Professor of Medicine Columbia University Medical Center and Director, Preventive Cardiology, NewYork-Presbyterian Hospital
© 2009 American Heart Association, Inc.