Researchers found that male and female hearts do not age in the same way. In a new study, notable gender variations in heart muscle aging were seen in imaging studies, prompting the need for gender-specific heart failure treatments.
Although the researchers, led by experts from Johns Hopkins, did not elaborate the exact reason as to why such difference occur, they said the findings may pave the way to understand more deeply the different forms of heart failure in men and women.
In the study, the researchers studied magnetic resonance imaging (MRI) scans of about 3,000 elderly people aged between 54 and 94. All the subjects had not been diagnosed with any preexisting cardiovascular condition. Between 2002 and 2012, the participants were followed at six U.S. hospitals, where each one was subjected to an MRI scan at the start of the research and 10 years later.
MRI scans enable clinicians to see the heart's interior and exterior structures, in three-dimensional images. With this, they are able to identify the size and volume of the heart muscle, which they add up with its density to calculate its weight.
The findings of the investigations showed that for a decade, the weight of the left ventricle, which is the chamber of the heart that initially pumps blood to the rest of its parts, increased by eight grams in men and decreased by 1.6 grams in women, on the average. The filling capacity of the heart, which is determined by the amount of blood that the left ventricle can hold, decreased by approximately 10 milliliters in men and 13 millimeters in women.
The results of the imaging scans were independent of risk factors that are determined to have an effect in the performance and size of the heart muscle. These factors include blood pressure, body weight, physical activity, smoking and cholesterol levels.
Dr. John Eng, lead author of the study and an associate professor of radiological science at the Johns Hopkins University School of Medicine said that enlarged heart muscle and smaller chambers both lead to increased risks of developing age-associated heart failure but in their study, the gender variations they found may mean that different sexes may develop the disease for varying reasons.
The authors explained that the left ventricle eventually decreases in size, resulting in lower amounts of blood to enter from the body to the heart and back again to the circulation. In the study, the authors found that the heart muscle that surrounds the ventricle enlarges and thickens in men and retains or somehow gets smaller in women.
João Lima, senior study author and the director of cardiovascular imaging at the Heart and Vascular Institute said that their findings are a notable presentation of the idea that heart disease may not have the same disease process on men and women and that there may be a need to individualize treatments according to this biological discrepancy.
The researchers said that the study was not made to look for the exact driving factor that influences the difference in cardiac function between the two genders, Nonetheless, they described the findings as a "fascinating discrepancy" that need further investigations.
"These results highlight the importance of longitudinal study and suggest sex-specific differences in age-related cardiac remodeling: the authors wrote. "Further research is needed to understand the mechanism behind these sex-specific differences."
The study was published in the journal Radiology on Tuesday, Oct. 20.
