In a study the team at Johns Hopkins analyzed more than half-dozen measurements of heart structure and pumping function to assess minute changes in the hearts of 5,004 men and women. Test results were obtained from study participants who had undergone high-tech magnetic resonance imaging of the heart - tagged MRI.
“Our results demonstrate just how the heart plays a losing game of catch-up as people age,” says Susan Cheng, M.D., a former medicine resident at Hopkins who led the study. She says the findings could lead to diagnostic tests to identify those whose hearts are aging faster than others, enabling preventive drug therapy, pacemakers, or lifestyle changes to slow or even reverse the deleterious effects.
Hopkins cardiologist João Lima, M.D., the senior study investigator, says effects of aging have been hard to determine because of inherent flaws in using standard criteria to assess heart function. The current gold standard, he says, is the heart’s ejection fraction. Study results showed that ejection fraction actually rose by 0.01 percent with every year. But Lima calls this figure misleading because the total amount of blood available for pumping, the bottom number in the ratio, decreases as the size of the heart cavity shrinks and heart walls thicken, falsely boosting test results when heart function is actually failing.
When researchers separated the numbers, the actual amount of blood pumped out by the heart fell by eight millilitres per year, says Lima. The flaw in using ratios, he notes, also helped to mask the gradual shrinkage of heart muscle mass. Researchers found that heart muscle mass declined by on average 0.3 grams per year. This occurred even though heart wall thickness had expanded and despite an increase in another standard measure of heart function, the ratio of left ventricular mass to blood volume, which went up by five milligrams per millilitre each year.
MEDICA.de; Source: Johns Hopkins Medical Institutions