Gender-related differences in left ventricular chamber function

Objectives: While women have lower rates of atherosclerotic disease than me n, they are more likely to suffer cardiac failure following infarction or c ardiac surgery, despite typically having a greater left ventricular (LV) ej ection fraction. We hypothesised that gender differences in systolic chambe r function and ventriculo-vascular coupling may contribute to these clinica l findings. Methods: LV chamber function was determined in a cohort of 30 p atients (16 women) aged 48-75 years with normal LV function using pressure- volume loops obtained by simultaneous conductance catheter volumetry and mi cromanometer pressure. End-systolic and end-diastolic pressure volume (ESPV R, EDPVR) and preload recruitable stroke work relations (PRSWR) were derive d. Results were analysed according to gender, and the effects of body size and chamber dimensions were examined. Results: The groups were closely matc hed for age (60+/-6 vs. 60+/-8 years) and co-morbid conditions. Women had h igher end-systolic blood pressure (139.7+/-21.1 vs. 123.6+/-12.6 mmHg, P=0. 001), and smaller LV cavity volume (end-diastolic volume 96.4+/-30.6 vs. 13 9+/-30.7 mi, P=0.001). Women had significantly higher LV end-systolic elast ance (Ees, 2.65+/-0.10 vs. 1.96+/-0.09 mmHg ml(-1), P<0.002), arterial elas tance (2.41+/-1.13 vs. 1.54+/-0.55 mmHg ml(-1), P=0.01) and lower passive L V diastolic compliance (slope EDPVR, 6.12+/-0.37 vs. 10.0+/-0.50 ml mmHg(-1 ), P<0.001). While there was a strong relationship between end-systolic ela stance and chamber volume (r=0.69, P<0.001), gender differences in chamber function all persisted after indexing to body size. Higher LV systolic func tion in women was also shown in PRSWR analysis (slope, M-SW; 101.4+/-3.8 vs . 90.4+/-2.8 mmHg, P<0.05), which is independent of chamber size. After nor malising volumes to resting diastolic volume, the greater systolic and dias tolic elastance in women was accounted for. The ratio of end-systolic to ar terial elastance, a measure of ventriculo-vascular coupling, was similar in women and men (1.19+/-0.40 vs. 1.54+/-0.30, respectively, P=0.23). Conclus ions: This study demonstrates greater systolic chamber function and lower d iastolic compliance in women. Within the range of chamber dimensions seen i n patients with normal LV function, a strong relationship was found between cardiac size and end-systolic elastance. While these differences were not accounted for by indexing to body size, the greater ventricular elastance i n women was removed after normalising to chamber size. Despite differences in resting ventricular elastance, appropriate ventriculo-vascular coupling was maintained in both genders as the greater end-systolic elastance in wom en was matched by similarly elevated arterial elastance. (C) 2001 Elsevier Science B.V. All rights reserved.