Reduced preload elicits increased LV twist in healthy humans

Hodt, Anders; Hisdal, Jonny; Stugaard, Marie; Stranden, Einar; Atar, Dan; Steine, Kjetil

doi:10.1111/j.1475-097x.2011.01029.x

Cited by 14 publications

(4 citation statements)

References 29 publications

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“…While the present study primarily manipulated vagal control, because of the integrative nature of cardiovascular regulation, concurrent alterations to LV preload and afterload may have influenced the observed responses of LV twist in men and women. Preload and afterload are key regulators of LV twist mechanics; both reductions and increases to LV preload can augment LV twist (17,35), and LV twist is reduced in the face of augmented afterload (10,36). In the present and previous (41) studies, men and women had similar relative reductions to LVEDV during LBNP without GLY.…”

Section: Influences Of LV Preload and Afterload On Sex Differences In Lv Mechanicssupporting

confidence: 67%

Influence of vagal control on sex-related differences in left ventricular mechanics and hemodynamics

Williams

Shave

Coulson

et al. 2018

American Journal of Physiology-Heart and Circulatory Physiology

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Left ventricular (LV) twist mechanics differ between men and women during acute physiological stress, which may be partly mediated by sex differences in autonomic control. While men appear to have greater adrenergic control of LV twist, the potential contribution of vagal modulation to sex differences in LV twist remains unknown. Therefore, the present study examined the role of vagal control on sex differences in LV twist during graded lower body negative pressure (LBNP) and supine cycling. On two separate visits, LV mechanics were assessed using two-dimensional speckle-tracking echocardiography in 18 men (22 ± 2 yr) and 17 women (21 ± 4 yr) during -40- and -60-mmHg LBNP and 25% and 50% of peak supine cycling workload with and without glycopyrrolate (vagal blockade). LV twist was not different at baseline but was greater in women during -60 mmHg in both control (women: 16.0 ± 3.4° and men: 12.9 ± 2.3°, P = 0.004) and glycopyrrolate trials (women: 17.7 ± 5.9° and men: 13.9 ± 3.3°, P < 0.001) due to greater apical rotation during control (women: 11.9 ± 3.6° and men: 7.8 ± 1.5°, P < 0.001) and glycopyrrolate (women: 11.6 ± 4.9° and men: 7.1 ± 3.6°, P = 0.009). These sex differences in LV twist consistently coincided with a greater LV sphericity index (i.e., ellipsoid geometry) in women compared with men. In contrast, LV twist did not differ between the sexes during exercise with or without glycopyrrolate. In conclusion, women have augmented LV twist compared with men during large reductions to preload, even during vagal blockade. As such, differences in vagal control do not appear to contribute to sex differences in the LV twist responses to physiological stress, but they may be related to differences in ventricular geometry. NEW & NOTEWORTHY This is the first study to specifically examine the role of vagal autonomic control on sex-related differences in left ventricular (LV) mechanics. Contrary to our hypothesis, vagal control does not appear to primarily determine sex differences in LV mechanical or hemodynamic responses to acute physiological stress. Instead, differences in LV geometry may be a more important contributor to sex differences in LV mechanics.

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Section: Influences Of LV Preload and Afterload On Sex Differences In Lv Mechanicssupporting

confidence: 67%

Influence of vagal control on sex-related differences in left ventricular mechanics and hemodynamics

Williams

Shave

Coulson

et al. 2018

American Journal of Physiology-Heart and Circulatory Physiology

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“…It has been proposed that changes to HR coincide with similar alterations to contractility and LV twist mechanics (Hodt et al . ). However, our data do not support this mechanistic link between HR and twist in females, as they experienced a greater reduction to HR without a significant reduction to LV twist.…”

Section: Discussionmentioning

confidence: 97%

The influence of adrenergic stimulation on sex differences in left ventricular twist mechanics

Williams

Shave

Cheyne

et al. 2017

The Journal of Physiology

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Sex differences in left ventricular (LV) mechanics exist at rest and during acute physiological stress. Differences in cardiac autonomic and adrenergic control may contribute to sex differences in LV mechanics and LV haemodynamics. Accordingly, this study aimed to investigate sex differences in LV mechanics with altered adrenergic stimulation achieved through post-handgrip-exercise ischaemia (PEI) and β -adrenergic receptor (AR) blockade. Twenty males (23 ± 5 years) and 20 females (22 ± 3 years) were specifically matched for LV length (males: 8.5 ± 0.5 cm, females: 8.2 ± 0.6 cm, P = 0.163), and two-dimensional speckle-tracking echocardiography was used to assess LV structure and function at baseline, during PEI and following administration of 5 mg bisoprolol (β -AR antagonist). During PEI, LV end-diastolic volume and stroke volume were increased in both groups (P < 0.001), as was end-systolic wall stress (P < 0.001). LV twist and apical rotation were not altered from baseline or different between the sexes; however, basal rotation increased in males (P = 0.035). During β -AR blockade, LV volumes were unchanged but blood pressure and heart rate were reduced in both groups (P < 0.001). LV apical rotation (P = 0.036) and twist (P = 0.029) were reduced in males with β -AR blockade but not females, resulting in lower apical rotation (males: 6.8 ± 2.1 deg, females: 8.8 ± 2.3 deg, P = 0.007) and twist (males: 8.6 ± 1.9 deg, females: 10.7 ± 2.8 deg, P = 0.008), and slower untwisting velocity (males: 68.2 ± 22.1 deg s , females: 82.0 ± 18.7 deg s , P = 0.046) compared to females. LV twist mechanics are reduced in males compared to females during reductions to adrenergic stimulation, providing preliminary evidence that LV twist mechanics may be more sensitive to adrenergic control in males than in females.

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“…The same twelve healthy male students as in a previous study, age 22 (2·3) years, height 183 (0·1) cm, weight 80 (9·5) kg and body mass index 24 (1·9) kg m −2 were included in the study (Hodt et al ., ). In one subject, the results of basal and papillary short‐axis levels were excluded based on the visual evaluation because of atypical paradoxical 2D movement of the antero‐septal wall.…”

Section: Methodsmentioning

confidence: 97%

“…By recently developed angle‐independent two‐dimensional (2D) speckle tracking imaging (STI), regional LV systolic deformation can now be assessed by echocardiography, similar to MRI (Helle‐Valle et al ., ; Cho et al ., ; Amundsen et al ., ). However, data by echocardiography on regional gradients of LV deformation between base and apex at end‐systole, similar to MRI, are limited and somewhat contradictory (Haendchen et al ., ; Andersen et al ., ; Becker et al ., ; Serri et al ., ; Amundsen et al ., ; Gustafsson et al ., ; Hodt et al ., ). Focusing on IVC, a recent animal study using sonomicrometry and tissue Doppler echocardiography (TDE) demonstrated LV shortening and volume reduction (Remme et al ., ), and other studies have shown LV untwist by STI in humans, reflecting the presence of isotonic contraction of myocardial fibres, and thereby challenging the IVC as a pure isometric condition (Helle‐Valle et al ., ; Notomi et al ., ; Kim et al ., ; Gustafsson et al ., ).…”

Section: Introductionmentioning

confidence: 97%

Regional LV deformation in healthy individuals during isovolumetric contraction and ejection phases assessed by 2D speckle tracking echocardiography

Hodt

Stugaard²,

Hisdal

et al. 2012

Clin Physio Funct Imaging

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Reduced preload elicits increased LV twist in healthy humans

Abstract: Preload reduction in normal LV elicits increased systolic CCR and regional area fraction at sub-papillary and apical levels as well as net twist angle. These findings might be of physiological importance to minimize reduction in stroke volume and maintain arterial blood pressure.

Cited by 14 publications

References 29 publications

Influence of vagal control on sex-related differences in left ventricular mechanics and hemodynamics

Influence of vagal control on sex-related differences in left ventricular mechanics and hemodynamics

The influence of adrenergic stimulation on sex differences in left ventricular twist mechanics

Regional LV deformation in healthy individuals during isovolumetric contraction and ejection phases assessed by 2D speckle tracking echocardiography

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