This is no gender war, but no less interesting. According to a new research, male and female hearts don’t grow old the same way. Led by investigators at Johns Hopkins University, the research points towards the need for gender-tailored treatments for age-related heart failure. An analysis of magnetic resonance imaging (MRI) scans of ageing hearts of nearly 3,000 adults showed significant differences in the way male and female hearts change over time.
The results of the study do not explain exactly what causes the sex-based differences, but they may shed light on different forms of heart failure seen in men and women that may require the development of gender-specific treatments.
The research is believed to be the first long-term follow-up using MRI showing how hearts change as they age. In both sexes, the main heart chamber, the left ventricle -- which fills with and then forces out blood -- gets smaller with time. As a result, less blood enters the heart and less gets pumped out to the rest of the body.
But in men, the study found, the heart muscle that encircles the chamber grows bigger and thicker with age, while in women, it retains its size or gets somewhat smaller. “Thicker heart muscle and smaller heart chamber volume both portend heightened risk of age-related heart failure but the gender variations we observed mean men and women may develop the disease for different reasons,” said lead investigator John Eng, associate professor of radiological science at the Johns Hopkins University School of Medicine.
Heart failure is marked by gradual “floppiness” and weakening of heart muscle and eventual loss of pumping ability. To lower the risk, cardiologists often prescribe medications designed to reduce the thickness of the heart muscle over time and boost cardiovascular performance.
But the finding that in women, the heart muscle tends to shrink or remain the same size means they may not derive the same benefit from such treatments, researchers said. For the study, researchers analysed MRI scans performed on nearly 3,000 older adults, ages 54 to 94, without pre-existing heart disease.
Participants were followed between 2002 and 2012, at six hospitals across the US where each one of them underwent MRI testing at the beginning of the study and once more after a decade. The MRI scans provided researchers with 3-D images of the heart’s interior and exterior, allowing them to determine the size and volume of the heart muscle. Adding these to the already known density of the muscle, they were able to calculate its weight.
Over a period of 10 years, the weight of the heart’s main pumping chamber -- the left ventricle -- increased by an average of 8gm in men and decreased by 1.6gm in women. The heart’s filling capacity -- marked by the amount of blood the left ventricle can hold between heartbeats -- declined in both sexes but more so in women, by about 13 millilitres, compared with just under 10 millilitres in men.
The research is published in the journal Radiology.