Preload Dependency of Left Ventricular Torsion

Weiner, Rory B.; Weyman, Arthur E.; Khan, Abigail; Reingold, Jason; Chen‐Tournoux, Annabel; Scherrer‐Crosbie, Marielle; Picard, Michael H.; Wang, Thomas J.; Baggish, Aaron L.

doi:10.1161/circimaging.109.932921

Cited by 74 publications

(87 citation statements)

References 35 publications

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“…Contrary to this hypothesis, early diastolic filling was not improved beyond normothermic baseline, possibly explained by the reduction in LV torsion, twisting rate, and untwisting rate during HDT heat stress, which appeared to be preload dependent. This result is in direct contrast with a recent report (33) that found that increasing preload (saline infusion) augmented peak systolic LV torsion and peak early diastolic untwisting rate. Two important differences exist between the present investigation and the aforementioned study (33), however, which likely contributes to this discrepancy.…”

Section: Diastolic Functioncontrasting

confidence: 99%

“…This result is in direct contrast with a recent report (33) that found that increasing preload (saline infusion) augmented peak systolic LV torsion and peak early diastolic untwisting rate. Two important differences exist between the present investigation and the aforementioned study (33), however, which likely contributes to this discrepancy. First, supine heat stress significantly alters heart rate, afterload [LV endsystolic wall stress (17)], preload, and contractility, whereas saline infusion appeared only to alter preload and systolic function (longitudinal, circumferential, and radial strain).…”

Section: Diastolic Functioncontrasting

confidence: 99%

See 1 more Smart Citation

Left ventricular systolic and diastolic function during tilt-table positioning and passive heat stress in humans

Nelson

Altamirano-Diaz

Petersen

et al. 2011

American Journal of Physiology-Heart and Circulatory Physiology

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The ventricular response to passive heat stress has predominantly been studied in the supine position. It is presently unclear how acute changes in venous return influence ventricular function during heat stress. To address this question, left ventricular (LV) systolic and diastolic function were studied in 17 healthy men (24.3 Ϯ 4.0 yr; mean Ϯ SD), using two-dimensional transthoracic echocardiography with Doppler ultrasound, during tilt-table positioning (supine, 30°h ead-up tilt, and 30°head-down tilt), under normothermic and passive heat stress (core temperature 0.8 Ϯ 0.1°C above baseline) conditions. The supine heat stress LV volumetric and functional response was consistent with previous reports. Combining head-up tilt with heat stress reduced end-diastolic (25.2 Ϯ 4.1%) and end-systolic (65.4 Ϯ 10.5%) volume from baseline, whereas heart rate (37.7 Ϯ 2.0%), ejection fraction (9.4 Ϯ 2.4%), and LV elastance (37.7 Ϯ 3.6%) increased, and stroke volume (Ϫ28.6 Ϯ 9.4%) and early diastolic inflow (Ϫ17.5 Ϯ 6.5%) and annular tissue (Ϫ35.6 Ϯ 7.0%) velocities were reduced. Combining head-down tilt with heat stress restored end-diastolic volume, whereas LV elastance (16.8 Ϯ 3.2%), ejection fraction (7.2 Ϯ 2.1%), and systolic annular tissue velocities (22.4 Ϯ 5.0%) remained elevated above baseline, and end-systolic volume was reduced (Ϫ15.3 Ϯ 3.9%). Stroke volume and the early and late diastolic inflow and annular tissue velocities were unchanged from baseline. This investigation extends previous work by demonstrating increased LV systolic function with heat stress, under varied levels of venous return, and highlights the preload dependency of early diastolic function during passive heat stress. tilt table; systolic function; left ventricle WHOLE BODY PASSIVE HEAT STRESS results in multiple cardiovascular and neural adjustments, including increases in cardiac output (14,17,29), cutaneous vascular conductance (2, 5), splanchnic and renal sympathetic vasoconstriction (15,26,28), and muscle sympathetic nerve activity (6,19). These responses occur in a coordinated effort to redistribute cardiac output to the cutaneous circulation, limit the reduction in blood pressure, and protect against syncope.In the supine heat-stressed individual, left ventricular (LV) end-diastolic volume is significantly reduced compared with normothermic conditions (17,18,34), along with reductions in central blood volume (5) and cardiac filling pressures (3,27,34,37). Despite this significant reduction in preload, stroke volume (SV) is maintained during passive heating (14,15,17,18,23,37), secondary to increased ventricular contractility (2,5,17,18) and ventricular diastolic suction (17, 18). While supine measures are helpful, an important and understudied issue is what happens when blood pressure control mechanisms are challenged during orthostasis. Likewise, because supine heat stress significantly reduces cardiac preload, an equally important issue is what happens to cardiac function when preload is restored.Passive postural changes by tilt-table...

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Section: Diastolic Functioncontrasting

confidence: 99%

Section: Diastolic Functioncontrasting

confidence: 99%

Left ventricular systolic and diastolic function during tilt-table positioning and passive heat stress in humans

Nelson

Altamirano-Diaz

Petersen

et al. 2011

American Journal of Physiology-Heart and Circulatory Physiology

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“…31 In a human study, investigators have demonstrated increased isovolumic untwist rate after increased preload. 32 In our study we also find larger LV volumes along with elevated s and LV minimum diastolic pressure in LVDD, suggesting that LV preload may be playing a role in increased untwist rate. On the other hand, no relationship between Àdφ 0 /dV 0 and LV volumetric or structural characteristics was found.…”

Section: Discussionsupporting

confidence: 73%

Left Ventricular Torsion Shear Angle Volume Approach for Non-Invasive Evaluation of Diastolic Dysfunction in Preserved Ejection Fraction

Gupta

Sharifov

Schiros

et al. 2017

Journal of the American College of Cardiology

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Background--Accurate noninvasive diagnostic tools for evaluating left ventricular (LV) diastolic dysfunction (LVDD) are limited in preserved LV ejection fraction. We previously proposed the relationship of normalized rate of change in LV torsion shear angle (φ 0 ) to corresponding rate of change in LV volume (V 0 ) during early diastole (represented as Àdφ 0 /dV 0 ) as a measure of LV diastolic function. We prospectively evaluated diagnostic accuracy of Àdφ 0 /dV 0 in respect to invasive LV parameters.

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“…Some previous reports indicate that systolic twisting is preload dependent, 5,8,9 whereas others have reported only a minor preload dependence or none at all. 10,11 We hypothesized that diastolic pressure has a direct effect on UTR similar to the effect of early-diastolic load on LV lengthening rate.…”

mentioning

confidence: 92%

“…1,3,6,7 It is not clear, however, whether LV relaxation and restoring forces are independent determinants of UTR. Furthermore, a recent study 8 showed increased UTR during volume loading, which tends to increase (slower relaxation) and ESV (decreased restoring forces), as well. Increased UTR despite slowed relaxation and reduced restoring forces suggests that UTR is not solely determined by these 2 factors.…”

mentioning

confidence: 95%

Myocardial Relaxation, Restoring Forces, and Early-Diastolic Load Are Independent Determinants of Left Ventricular Untwisting Rate

et al. 2012

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Background-Peak left ventricular (LV) untwisting rate (UTR) has been introduced as a clinical marker of diastolic function. This study investigates if early-diastolic load and restoring forces are determinants of UTR in addition to the rate of LV relaxation. Methods and Results-In 10 anesthetized dogs we measured UTR by sonomicrometry and speckle tracking echocardiography at varying LV preloads, increased contractility, and myocardial ischemia. UTR was calculated as the time derivative of LV twist. Because preload modified end-diastolic twist, LV systolic twist was calculated in absolute terms with reference to the end-diastolic twist configuration at baseline. Relaxation rate was measured as the time constant () of LV isovolumic pressure decay. Early-diastolic load was measured as LV pressure at the time of mitral valve opening. Circumferential-longitudinal shear strain was used as an index of restoring forces. In a multivariable mixed model analysis a strong association was observed between UTR and LV pressure at the time of mitral valve opening (parameter estimate [␤]ϭ6.9; PϽ0.0001), indicating an independent effect of early-diastolic load. Furthermore, the associations between UTR and circumferential-longitudinal shear strain (␤ϭϪ11.3; PϽ0.0001) and (␤ϭϪ1.6, PϽ0.003) were consistent with independent contributions from restoring forces and rate of relaxation. Maximal UTR before mitral valve opening, however, was determined only by relaxation rate and restoring forces. Conclusions-The present study indicates that early-diastolic load, restoring forces, and relaxation rate are independent determinants of peak UTR. However, only relaxation rate and restoring forces contributed to UTR during isovolumic relaxation.

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Preload Dependency of Left Ventricular Torsion

Cited by 74 publications

References 35 publications

Left ventricular systolic and diastolic function during tilt-table positioning and passive heat stress in humans

Left ventricular systolic and diastolic function during tilt-table positioning and passive heat stress in humans

Left Ventricular Torsion Shear Angle Volume Approach for Non-Invasive Evaluation of Diastolic Dysfunction in Preserved Ejection Fraction

Myocardial Relaxation, Restoring Forces, and Early-Diastolic Load Are Independent Determinants of Left Ventricular Untwisting Rate

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