Transient modification of baroreceptor response during tilt-induced vasovagal syncope

Samniah, Nemer; Sakaguchi, Scott; Ermis, Cengiz; Lurie, Keith G.; Benditt, David G.

doi:10.1016/j.eupc.2003.09.004

Cited by 37 publications

(31 citation statements)

References 13 publications

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“…Normal response to sudden volume loading of central circulation is bradycardia and diminished vasoconstriction due to sympathetic inhibition. On contrary to an expected response, acceleration of heart rate and increase in blood pressure was reported as a manifestation of decreased barorefl ex activity in position change from upright to supine position (18).…”

Section: Discussionmentioning

confidence: 96%

Reduced baroreflex sensitivity in patients with vasovagal syncope

Mitro¹,

Šimurda²,

Evin³

et al. 2015

BLL

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OBJECTIVES: The evidence is confl icting regarding the role of barorefl ex in patients with vasovagal syncope. The aim of the study was to measure barorefl ex sensitivity (BRS) and hemodynamic parameters during head up tilt test (HUT) with nitroglycerine stimulation. METHODS: Nitroglycerine stimulated HUT was performed in 51 patients with the history of recurrent syncope (mean age 46± 19 years, 18 men, 23 women). Cardiac output (CO), stroke volume (SV), left-ventricular ejection time (LVET) and total peripheral resistance (TPR) were assessed during HUT by volume-clamp method using a beat-to-beat photopletysmography. Spontaneous BRS sensitivity was computed using a sequential BRS calculation. RESULTS: HUT was positive after nitroglycerine administration in 28 patients and negative in 23 patients. BRS was lower at the time of syncope in HUT positive group compared to end-test values in HUT negative group (0.54±0.27 vs 0.72±0.35, p = 0. 03). At the time of syncope, CO was signifi cantly lower in HUT positive patients compared to HUT negative patients (2.6±1.4 vs 4.3±1.4 l/min, p < 0.0001), similarly as SV (34.7±14.7 vs 49.2±19 ml, p=0.005 ). LVET was signifi cantly higher in syncopal patients (282.27±26.2 vs 240.5±58.8 ms, p=0.002) and TPR did not differ between two groups. CONCLUSIONS: Reduced BRS may contribute to the development of the vasovagal syncope by inability to adequately counteract hypotension resulting from decreased cardiac output at the time of syncope (Tab. 3, Ref. 18). Text in PDF www.elis.sk.

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Section: Discussionmentioning

confidence: 96%

Reduced baroreflex sensitivity in patients with vasovagal syncope

Mitro¹,

Šimurda²,

Evin³

et al. 2015

BLL

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“…With respect to the effects of upright tilting itself on arterial baroreflex function, this has also only been examined in younger populations. 30 As shown in Figure 2, upright tiling itself results in a decrease in BRS in older adults, and this decrease is augmented in TT+ subjects. The TT+ group decreased BRS by approximately 60 % compared with a 45 % decrease in the TT-group.…”

Section: Discussionmentioning

confidence: 99%

Arterial baroreflex function in older adults with neurocardiogenic syncope

Madden¹,

Lockhart²

2009

CIM

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Clin Invest Med 2009; 32 (3): E191-E198. AbstractPurpose: Neurocardiogenic syncope (formerly vasovagal) accounts for large numbers of falls in older adults and the mechanisms are poorly understood. This study examined the differences in baseline arterial baroreflex function in older adults with and without a neruocardiovascular response to orthostatic stress. Methods: Subjects were divided into two groups based on the presence (TT+ group) or absence (TT-group) of a neurocardiovascular response to upright tilting (70 degree head-up tilt for 10 minutes after 400 micrograms of sublingual nitroglycerin). A neurocardiovascular response was defined as presyncopal symptoms (lightheadedness) in association with at least a 30 mm Hg decrease in blood pressure. Before being divided into groups, baroreflex function was assessed using the spontaneous baroreflex method (baroreflex sensitivity, BRS). This method involves the analysis of "spontaneous" swings in blood pressure and heart rate that are mediated by the arterial baroreflexes. Results: 42 older adults (mean age 70.3±0.7 yr) were recruited, of which 18 were in the TT+ and 24 were in the TT-group. At baseline, the TT+ group demonstrated increased arterial baroreflex sensitivity in response to negative blood pressure sequences only (BRSdown, 11.2±1.9 vs. 7.3±1.0 ms/mm Hg, P=0.011). During tilt, the TT+ group demonstrated a much larger decrease in overall arterial baroreflex sensitivity than the TT-group (-6.8±1.2 vs. -3.2±0.9 ms/mm Hg, P=0.012). There was a negative correlation between BRSdown and length of tilt table test (r=-0.329, P=0.041) in the TT+ subjects. Conclusion: Older adults with neurocardiogenic syncope have exaggerated arterial baroreflex sensitivity at baseline.

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“…We are not searching for a shutting down of the reflex, but for a different kind of alteration. A recent study found that an increase in blood pressure of 1 mm Hg led to an RR interval prolongation of 3 to 6 ms in healthy controls [4]. In other words, an increase in blood pressure caused a slowing of heart rate, which is as it should be.…”

Section: In a Sweat Over The Riddle Of Reflex Syncopementioning

confidence: 96%

In a sweat over the riddle of reflex syncope

Dijk

2004

Clin Auton Res

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Transient modification of baroreceptor response during tilt-induced vasovagal syncope

Cited by 37 publications

References 13 publications

Reduced baroreflex sensitivity in patients with vasovagal syncope

Reduced baroreflex sensitivity in patients with vasovagal syncope

Arterial baroreflex function in older adults with neurocardiogenic syncope

In a sweat over the riddle of reflex syncope

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