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Females have greater left ventricular twist mechanics than males during acute reductions to preload

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journal contribution
posted on 2023-01-24, 12:08 authored by Alexandra M.Williams, Rob Shave, Michael StembridgeMichael Stembridge, Neil D. Eves

 Compared to males, females have smaller left ventricular (LV) dimensions and volumes, higher ejection fractions (EF), and higher LV longitudinal and circumferential strain. LV twist mechanics determine ventricular function and are preload-dependent. Therefore, the sex differences in LV structure and myocardial function may result in different mechanics when preload is altered. This study investigated sex differences in LV mechanics during acute challenges to preload. With the use of conventional and speckle-tracking echocardiography, LV structure and function were assessed in 20 males (24 ± 6.2 yr) and 20 females (23 ± 3.1 yr) at baseline and during progressive levels of lower body negative pressure (LBNP). Fourteen participants (8 males, 6 females) were also assessed following a rapid infusion of saline. LV end-diastolic volume, end-systolic volume, stroke volume (SV), and EF were reduced in both groups during LBNP (P < 0.001). While males had greater absolute volumes (P < 0.001), there were no sex differences in allometrically scaled volumes at any stage. Sex differences were not detected at baseline in basal rotation, apical rotation, or twist. Apical rotation and twist increased in both groups (P < 0.001) with LBNP. At −60 mmHg, females had greater apical rotation (P = 0.009), twist (P = 0.008), and torsion (P = 0.002) and faster untwisting velocity (P = 0.02) than males. There were no differences in mechanics following saline infusion. Females have larger LV twist and a faster untwisting velocity than males during large reductions to preload, supporting that females have a greater reliance on LV twist mechanics to maintain SV during severe reductions to preload. 

Funding

This research was supported by a Discovery Grant from the Natural Sciences and Engineering Research Council of Canada (371950-2013) and a Clinical Scholar Award from the Michael Smith Foundation for Health Research (7085) (to N. D. Eves)

History

Published in

American Journal of Physiology - Heart and Circulatory Physiology

Publisher

American Physiological Society

Version

AM (Accepted Manuscript)

Citation

Williams, A. M., Shave, R., Stembridge, M. & Eves, N. (2016) 'Females have greater left ventricular twist mechanics than males during acute reductions to preload', American Journal of Physiology - Heart and Circulatory Physiology, 311 (1), pp. 76-84. DOI: 10.1152/ajpheart.00057.2016

Print ISSN

0363-6135

Electronic ISSN

1522-1539

Cardiff Met Affiliation

  • Cardiff School of Sport and Health Sciences

Cardiff Met Authors

Mike Stembridge

Cardiff Met Research Centre/Group

  • Cardiovascular Physiology

Copyright Holder

© The Publisher

Language

en