Jan. 8, 2003 ROCHESTER, Minn. -- More than one-fourth of adults over age 45 have abnormalities in the way their heart fills with blood and are at significantly increased risk for premature death, according to results of a study of 2,042 randomly selected residents of Olmsted County, Minn. The study is published in the Jan. 8 issue of the Journal of the American Medical Association (JAMA).
Individuals with diastolic dysfunction, or problems with the heart's filling with blood between beats, were eight to 10 times more likely to die within five years than those with normal filling. According to the study's lead author, the findings point to the need for better understanding of diastolic heart failure and how it can be prevented.
"Many people think of heart failure as being due to a large, weakly pumping heart," says Margaret Redfield, M.D., director of the Mayo Clinic Heart Failure Clinic. "This is called systolic heart failure, when the ejection fraction -- the portion of the blood in the left ventricle pushed out to the body with each beat -- is less than 50 percent. But this study shows that for nearly half of heart failure patients, pumping function is normal, but the heart is stiff or does not relax and therefore cannot fill with blood properly. This is diastolic heart failure."
Heart failure is an end-stage syndrome that may arise from various cardiovascular diseases, such as hypertension, coronary artery disease or cardiomyopathies. Symptoms typically include shortness of breath, fatigue, swelling of the legs and heart rhythm problems.
Dr. Redfield says the study's most important finding is the increased all-cause mortality among people who have some ventricular dysfunction -- either diastolic or systolic -- over half of whom have not yet been recognized as having heart failure.
"People all along the continuum of dysfunction from mild impairment to full-blown heart failure are at increased risk of dying," says Dr. Redfield. "Just over 2 percent of the population is in heart failure at any one time, and over half of those patients fail to survive five years. A larger group has either a weakly pumping heart or moderate to severe problems in the heart's filling but has not been diagnosed with heart failure and may not even have any symptoms. Those patients are about 10 times more likely to die within five years than are other people of the same age and sex. Finally, more than 20 percent had mild diastolic dysfunction, which was associated with an eightfold increase in mortality compared with those with normal heart filling."
Dr. Redfield says more research is needed to find cost-effective ways to identify people with filling dysfunction and to prevent their condition from worsening to become heart failure. "Many of the methods used to detect diastolic dysfunction were developed in the Mayo Clinic echocardiography laboratory, but they are not practical to use in screening the general population. Moreover, even though aggressive treatment in a heart failure clinic can prevent further deterioration in patients with pumping dysfunction, there are no proven therapies for filling dysfunction.
"While we continue to investigate new screening techniques and treatments for heart failure and ventricular dysfunction, we should emphasize helping patients reduce or eliminate known risk factors, including high blood pressure and high cholesterol. These are easy to test and can be modified through diet, physical activity and medication. With broad-based risk factor reduction, and as we develop better ways to identify and intervene with patients who are just starting to slip into ventricular dysfunction, we may be able to slow the growth of the heart failure epidemic," Dr. Redfield concludes.
Other authors of the paper, "Burden of Systolic and Diastolic Ventricular Dysfunction in the Community," include Steven Jacobsen, M.D.; Ph.D., John Burnett, Jr., M.D.; Kent Bailey, Ph.D.; Richard Rodeheffer, M.D.; and Douglas Mahoney.
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