Changes in left ventricular volume during head-up tilt in patients with vasovagal syncope: An echocardiographic study

Yamanouchi, Yoshio; Jaalouk, Safwan; Shehadeh, Abbas; Jaeger, Fredrick J.; Goren, Hershel; Fouad‐Tarazi, Fetnat M.

doi:10.1016/s0002-8703(96)90053-8

Cited by 40 publications

(26 citation statements)

References 13 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The present study also confirms that a greater decrease in LV end-diastolic volume occurs during upright tilt in patients who develop neurally mediated syncope than in those who do not 3,4,16,17 and that these patients have a lower percent thickening of the inferior wall, where the greatest density of C-fibers are thought to be located. 18 Despite data suggesting that the activation of LV mechanoreceptors correlates linearly with LV end-diastolic pressure 19 and that enhanced contrac- tility may have a synergistic (but not independent) effect on receptor discharge, it has also been shown that acute hemorrhage (unloading of the left ventricle) triggers a paradoxical increase in mechanoreceptor activation.…”

Section: Discussionsupporting

confidence: 85%

Left Ventricular Geometry and Function Preceding Neurally Mediated Syncope

et al. 2000

View full text Add to dashboard Cite

Background-Neurally mediated syncope has been associated with increased left ventricular (LV) fractional shortening (FS) during tilt testing, which is consistent with the hypothesis that the stimulation of LV mechanoreceptors leads to reflex hypotension and/or bradycardia. However, FS does not represent true LV contractility because of its dependence on afterload and preload. Methods and Results-To elucidate the role of increased contractility in the mediation of neurally mediated syncope, we compared echocardiographic measures of LV performance corrected for end-systolic stress (ESS) in 21 patients (13 women and 8 men) with unexplained syncope who had either positive (nϭ10) or negative (nϭ11) responses to a tilt-table test. Two-dimensional echocardiographic LV imaging was performed at baseline and during the initial 5 minutes of upright tilt. In the supine position, both groups had similar LV end-diastolic volume indexes, stroke volumes, FS, circumferential ESS, and afterload-independent measures of LV performance (stress-corrected midwall and FS). However, after 5 minutes of upright tilt, patients who subsequently had a positive test had a lower stroke volume, lower stress-corrected midwall shortening, and endocardial FS. The tilt-positive group also had a greater fall in ESS and FS early during upright tilt. Conclusions-Reduced ESS, LV volume, and chamber function during initial upright tilt are associated with a subsequent positive tilt response in patients with unexplained syncope. These data suggest that if paradoxic activation of LV mechanoreceptors has a role in mediating neurally mediated syncope, it is not triggered by LV hypercontractility or increased systolic wall stress during the initial period of upright tilt. (Circulation. 2000;101:777-783.)

show abstract

Section: Discussionsupporting

confidence: 85%

Left Ventricular Geometry and Function Preceding Neurally Mediated Syncope

et al. 2000

View full text Add to dashboard Cite

show abstract

“…The reduction in SV that we and other authors 11,17,32,35 observed before loss of consciousness might be related not only to a reduced venous return but also to an impairment of myocardial contractility. In this regard, the literature offers rather contrasting data.…”

Section: Previous Studiessupporting

confidence: 61%

“…15 During the first and intermediate phases of TT, the reduction or the rate of reduction in SV or end-diastolic volume has been seen to be greater in patients with positive TT than in controls. 11,12,14,17,18 In the studies by de Jong-de Vos van Steenwijk et al 21 and Novak et al, 23 a decrease in SV and CO was not observed in patients with positive TT before loss of consciousness, and hypotension appeared secondary to a fall in calculated TPR. However, the former study investigated paediatric subjects without a history of spontaneous syncope, who might show a different haemodynamic behaviour.…”

Section: Previous Studiesmentioning

confidence: 94%

“…Some authors 36,37 have reported a fall of dP/dt max or peak endocardial acceleration just before loss of consciousness; others 38,39 have not observed this fall. In most studies, 12,32,40 left ventricular ejection fraction or fractional shortening increased before tilt-induced syncope; in others, 14,17 a decrease or a nonsignificant change has been reported. On the basis of the present knowledge, there is no evidence for left ventricular systolic dysfunction before loss of consciousness.…”

Section: Previous Studiesmentioning

confidence: 98%

See 1 more Smart Citation

The venous system is the main determinant of hypotension in patients with vasovagal syncope

Fucà

Dinelli

Suzzani³

et al. 2006

EP Europace

View full text Add to dashboard Cite

Aims In patients with vasovagal syncope (VVS), a neural reflex appears the main determinant of hypotension leading to loss of consciousness; whether hypotension is mainly due to involvement of the arterial system or the venous system remains a debated issue. The aim of the present study was to assess which of these two systems is responsible for the fall in blood pressure (BP) in patients with VVS; to this end, a haemodynamic study was carried out not only before and during loss of consciousness but also during the recovery phase. Methods and results Beat-to-beat recordings of heart rate (HR), BP (volume-clamp method) and stroke volume (SV) (modelflow method), cardiac output (CO), and total peripheral resistance (TPR) were made at rest, during unmedicated tilt testing (TT) and recovery from loss of consciousness in 18 patients with a history of syncope (age 45 + 23 years) and positive response to TT. Blood pressure showed a significant fall during prodromal symptoms and a further fall at the beginning of loss of consciousness, together with a fall in SV, CO, and HR, and a slight, but significant, increase in TPR. At the beginning of recovery, BP showed a significant increase and a further increase 5 min later, together with an increase in SV, CO, and HR without significant changes in TPR. Conclusion These results suggest that in VVS the fall in BP is mainly caused by reduced venous return to the heart. The arterial system does not appear to be the main determinant of the fall of BP; however, the system appears unable to make the appropriate compensatory changes.

show abstract

“…First, P-NE levels have been found to be normal or decreased preceding VVS (42)(43)(44)(45) and reduced maximal increase in MSNA has been found in patients developing VVS (44,46). Further, echocardiographic measurements during head up tilt (HUT) have not reliably demonstrated decreased left ventricular size or volume before the onset of syncope (47,48). Second, there is evidence that VVS can be evoked in patients with cardiac transplantations, i.e., when the heart has undergone major efferent and afferent denervation (49).…”

Section: Pathophysiology Of Vasovagal Syncopementioning

confidence: 99%

Cardiovascular regulation in women with vasovagal syncope : With special reference to the venous system

Skoog¹

2016

Linköping University Medical Dissertations

View full text Add to dashboard Cite

Changes in left ventricular volume during head-up tilt in patients with vasovagal syncope: An echocardiographic study

Cited by 40 publications

References 13 publications

Left Ventricular Geometry and Function Preceding Neurally Mediated Syncope

Left Ventricular Geometry and Function Preceding Neurally Mediated Syncope

The venous system is the main determinant of hypotension in patients with vasovagal syncope

Cardiovascular regulation in women with vasovagal syncope : With special reference to the venous system

Contact Info

Product

Resources

About