Effect of Gravitational Gradients on Cardiac Filling and Performance

Negishi, Kazuaki; Borowski, Allen G.; Popović, Zoran B.; Greenberg, Neil L.; Martin, David S.; Bungo, Michael W.; Levine, Benjamin D.; Thomas, James D.

doi:10.1016/j.echo.2017.08.005

Cited by 53 publications

(50 citation statements)

References 30 publications

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“…Furthermore, the authors observed an ß15% (62 ± 11 to 53 ± 6 ml) reduction in LV stroke volume following head-up tilt, which was taken as evidence of a loss of sympathetically mediated vasoconstriction. However, this stroke volume response is similar to that observed in able-bodied individuals following 41°whole-body tilt (63 ± 15 to 55 ± 14 ml; ß13%) (Negishi et al 2017). This evidence suggests that the reduction in LV end-diastolic volume and stroke volume in SCI athletes probably reflects the typical, but substantial, effect of an elevated gravitational load on venous return and preload.…”

Section: Orthostatic Intolerancesupporting

confidence: 71%

“…However, this stroke volume response is similar to that observed in able‐bodied individuals following 41° whole‐body tilt (63 ± 15 to 55 ± 14 ml; ∼13%) (Negishi et al . ). This evidence suggests that the reduction in LV end‐diastolic volume and stroke volume in SCI athletes probably reflects the typical, but substantial, effect of an elevated gravitational load on venous return and preload.…”

Section: Orthostatic Intolerancementioning

confidence: 97%

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Respiratory muscle training in spinal cord injury: a breath of fresh air for the heart

Dawkins

Curry

2019

The Journal of Physiology

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Section: Orthostatic Intolerancesupporting

confidence: 71%

Section: Orthostatic Intolerancementioning

confidence: 97%

Respiratory muscle training in spinal cord injury: a breath of fresh air for the heart

Dawkins

Curry

2019

The Journal of Physiology

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“…Those severe fast-changing conditions heavily question how the human body and brain react to this unique experience of being weightless and the straining phases of hypergravity. Indeed, operators’ tasks and subjects’ testing, working on-board require cognitive performances while environmental constraint remains high including stress, tiredness, strong cardiovascular stimulation ( Negishi et al, 2017 ), attention and emotional states changes ( Collado et al, 2017 ), risk of motion sickness ( Golding et al, 2017 ). However, the continuous cognitive monitoring all along the flight remains challenging although its evaluation appears crucial particularly during biomedical experiments.…”

Section: Introductionmentioning

confidence: 99%

Critical Flicker Fusion Frequency: A Marker of Cerebral Arousal During Modified Gravitational Conditions Related to Parabolic Flights

et al. 2018

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In situ evaluation of human brain performance and arousal remains challenging during operational circumstances, hence the need for a rapid, reliable and reproducible tool. Here we hypothesized that the Critical flicker fusion frequency (CFFF) reflecting/requiring visual integration, visuo-motor skills and decision-taking process might be a powerful, fast and simple tool in modified gravity environments. Therefore 11 male healthy volunteers were assessed for higher cognitive functions with CFFF during parabolic flights. They were assessed at different time points: upon arrival to the base, 30 min after subcutaneous scopolamine administration, before parabolas, during hypergravity and microgravity at break time (between the 16th and the 17th parabola), on the return flight and on the ground after landing. First, a stable, and consistent measurement of CFFF could be obtained within 12 s. Second, under modified gravitational conditions, the perceptual ability of participants is significantly modified. Compared to the baseline, evolution is characterized by a significant increase of CFFF when in microgravity (0g: 106.9 ± 5.5%), and a significant decrease of CFFF while in hypergravity (2g: 94.5 ± 3.8%). Other time-points were not statistically different from the baseline value. Although the underlying mechanism is still debated, we suggest that the CFFF test is a global marker of cerebral arousal as the result of visuo-motor and decision taking testing based on a simple visual stimulus with an uncomplicated set up that could be used under various environmental conditions. The authors express an opinion that it would be advisable to introduce CFFF measurement during spaceflights as it allows individual longitudinal assessment of individual ability even under conditions of incomplete physiological compensation, as shown here during parabolic flights.

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“…Importantly, STE-derived strain rate has been shown to be more robust to dynamic ventricular unloading than strain in several well-performed animal experimental studies [ 29 – 31 ]. In humans, LV strain has been shown to be affected by changes in cardiac loading conditions such as hemodialysis [ 32 ] or gravitational gradients [ 33 ]. Furthermore, other than strain, strain rate has been demonstrated to be unaffected by preload and correlate well with end systolic elastance as verified by invasive catheterization [ 18 ].…”

Section: Discussionmentioning

confidence: 99%

Novel functional advanced echocardiography for the assessment of myocardial mechanics in children with neurocardiogenic syncope – a blinded prospective speckle tracking head-up tilt-table challenge study

Hensel

Roskopf

Schneyder

et al. 2018

BMC Cardiovasc Disord

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BackgroundData on left ventricular (LV) function in patients with neurocardiogenic syncope (NS) is conflicting in adults and lacking in children. The aim of this study was to analyze LV myocardial performance in children with NS at rest and during head-up tilt-table (HUTT) testing.MethodsThis is the first study to combine HUTT and speckle-tracking echocardiography (STE) in children with NS. 43 consecutive normotensive pediatric patients with NS (mean age 13.9 ± 2.6 years, 51% female) and 41 sex- and age-matched healthy controls were included in the study. The study groups consisted of 21 patients with a positive HUTT reaction (HUTT+) and 22 with a negative HUTT reaction (HUTT-). STE was used to analyze peak systolic LV myocardial strain and strain rate.ResultsConventional echocardiographic parameters were similar in all analyzed groups. When compared to healthy controls, children with NS had depressed levels of circumferential strain rate (p = 0.032) and significantly depressed longitudinal strain rate (p < 0.001) at rest. Interestingly, during HUTT testing LV global strain and strain rate were similar in both groups. LV strain rate was lowest in HUTT+ followed by HUTT- and control subjects both at rest and during HUTT.ConclusionsResting LV longitudinal strain rate is attenuated in children with NS, especially in those with a positive HUTT response. This is further evidence that NS patients feature altered cardiac mechanics rendering them prone to vasovagal perturbations that can ultimately result in collapse.Trial registrationWitten/Herdecke University ethics committee clinical study number: UWH-73-2014.

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Effect of Gravitational Gradients on Cardiac Filling and Performance

Cited by 53 publications

References 30 publications

Respiratory muscle training in spinal cord injury: a breath of fresh air for the heart

Respiratory muscle training in spinal cord injury: a breath of fresh air for the heart

Critical Flicker Fusion Frequency: A Marker of Cerebral Arousal During Modified Gravitational Conditions Related to Parabolic Flights

Novel functional advanced echocardiography for the assessment of myocardial mechanics in children with neurocardiogenic syncope – a blinded prospective speckle tracking head-up tilt-table challenge study

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