Impact of estradiol, testosterone and their ratio on left and right auricular myofilament function in male and female patients undergoing coronary artery bypass grafting

The impact of sex hormones on right and left auricular contractile apparatus function is largely unknown. We evaluated the impact of sex hormones on left and right heart contractility at the level of myocardial filaments harvested from left and right auricles during elective coronary artery bypass surgery.

This study shows that patients' comorbidities influence left and right sided contractility and may blur results concerning influence of sex hormones if not eliminated. A sex hormone dependent influence is obvious with different effects on the left and right ventricle. The E/T ratio and its impact on myofilament top force showed divergent results between genders, and may partially explain gender differences in patients with cardiovascular disease.

150 patients (132 male; 18 female) were enrolled. Preoperative testosterone and estradiol levels were measured with Immunoassay. Calcium induced force measurements were performed with left- and right auricular myofilaments in a skinned fiber model. Correlation analysis was used for comparison of force values and levels of sex hormones and their ratio.

Low testosterone was associated with higher top force values in right-sided myofilaments but not in left-sided myofilaments for both sexes (p = 0.000 in males, p = 0.001 in females). Low estradiol levels were associated with higher top force values in right-sided myofilaments (p 0.000) in females and only borderline significantly associated with higher top force values in males (p 0.056). In females, low estradiol levels correlated with higher top force values in left sided myofilaments (p 0.000). In males, higher Estradiol/Testosterone ratio (E/T ratio) was only associated with higher top force values from right auricular myofilaments (p 0.04) In contrast, in females higher E/T ratio was associated with lower right auricular myofilament top force values (p 0.03) and higher top force values in left-sided myofilaments (p 0.000). Conclusions: This study shows that patients' comorbidities influence left and right sided contractility and may blur results concerning influence of sex hormones if not eliminated. A sex hormone dependent influence is obvious with different effects on the left and right ventricle. The E/T ratio and its impact on myofilament top force showed divergent results between genders, and may partially explain gender differences in patients with cardiovascular disease.