Effects of gender, ejection fraction and weight on cardiac force development in patients undergoing cardiac surgery – an experimental examination

Abstract

BackgroundIt has long been recognized that differences exist between men and women in the impact of risc factors, symptoms, development and outcome of special diseases like the cardiovascular disease. Gender determines the cardiac baseline parameters like the number of cardiac myocyte, size and demand and may suggest differences in myofilament function among genders, which might be pronounced under pathological conditions. Does gender impact and maybe impair the contractile apparatus? Are the differences more prominent when other factors like weight, age, ejection fraction are added?Therefore we performed a study on 36 patients (21 male, 15 female) undergoing aortic valve replacement (AVR) or aortocoronary bypass operation (CABG) to examine the influence of gender, ejection fraction, surgical procedure and body mass index (BMI) on cardiac force development.MethodsTissue was obtained from the right auricle and was stored in a special solution to prevent any stretching of the fibers. We used the skinned muscle fiber model and single muscle stripes, which were mounted on the “muscle machine” and exposed to a gradual increase of calcium concentration calculated by an attached computer program.Results1.) In general female fibers show more force than male fibers: 3.9 mN vs. 2.0 mN (p = 0.03) 2.) Female fibers undergoing AVR achieved more force than those undergoing CABG operation: 5.7 mN vs. 2.8 mN (p = 0.02) as well as male fibers with AVR showed more force values compared to those undergoing CABG: 2.0 mN vs. 0.5 mN (p = 0.01). 3.) Male and female fibers of patients with EF > 55% developed significantly more force than from those with less ejection fraction than 30%: p = 0.002 for the male fibers (1.6 vs. 2.8 mN) and p = 0.04 for the female fibers (5.7 vs. 2.8 mN). 4.) Patients with a BMI between 18 till 25 develop significant more force than those with a BMI > 30: Females 5.1 vs. 2.6 mN; p 0.03, Males 3.8 vs. 0.8 mN; p 0.04).ConclusionOur data suggest that female patients undergoing AVR or CABG develop significantly more force than male fibers. Additionally we could image the clinical impression of negative impact of overweight and obesity as well as low ejection fraction on cardiac function on level of the myofilaments and observed a reduced force capacity, which is more prominent in male fibers.

Myofilament function and body mass index

“…Diabetes seems to reduce even more contractile force in humans as well as in animals. We observed this difference to be more pronounced in patients undergoing AVR, as previously identified ( 13 ).…”

Estrogen regulation of cardiac cAMP-L-type Ca2+ channel pathway modulates sex differences in basal contraction and responses to β2AR-mediated stress in left ventricular apical myocytes

“…Male and female hearts have well-known structural and functional differences [1–3]. However, investigations on the mechanisms that underlie these differences have not yielded a consistent conclusion.…”

Trait anxiety mediates the effect of stress exposure on post-traumatic stress disorder and depression risk in cardiac surgery patients

“…First, the study population included more male (78%) than female patients (22%) which is typical for a cardiac surgery cohort (Bening et al, 2013) but might limit the generalizability of our findings. Second, the presence of PTSD and depressive symptoms is based on validated questionnaires by mail instead of a diagnostic interview (Hovens et al, 2000;van Zelst et al, 2003b;Beck et al, 1996aBeck et al, , 1996b.…”