The structure and function of the heart’s right ventricle (RV) may be determined by sex hormones, according to a study published in the American Journal of Respiratory and Critical Care Medicine.

For this trial, researchers took blood samples and magnetic resonance imaging (MRI) scans of more than 3,600 people aged 45 to 84 years, which included postmenopausal women. The blood samples were used to measure each individual’s sex hormone levels, and the MRIs allowed the team to examine the heart structure of each participant.

The results showed that only women undergoing hormone therapy with high estrogen levels had higher RV ejection fraction and lower RV end-systolic volume, which both contribute to the heart’s efficiency to pump blood. Also, higher testosterone levels in men and an increased amount of DHEA, a compound that improved blood pressure in animals, in women not receiving hormone treatments caused larger RV mass and higher volumes.

Corey E. Ventetulo, lead author of the study, stated that this study shows “differences in RV structure that go beyond the sexes and may depend on specific hormone levels.” He concluded that fiurther research will be needed to determine “whether the increased RV mass seen with higher hormone levels is helpful or harmful.”

In 2008, a total of approximately 23 percent of women who used hormone treatments for menopause used oral medications, the North American Menopause Society reports.