Failure of Reflex Venoconstriction During Exercise in Patients With Vasovagal Syncope

Thomson, Helen L.; Atherton, J.; Khafagi, Frederick A.; Frenneaux, Michael

doi:10.1161/01.cir.93.5.953

Cited by 68 publications

(39 citation statements)

References 23 publications

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“…It is also possible to assess venous tone in the forearm capacitance bed by radionuclide venous plethysmography 51) . This technique involves labeling red blood cells with technetium-99m ( 99m Tc).…”

Section: Peripheral Arterial Tonometrymentioning

confidence: 99%

Testing Endothelial Function and its Clinical Relevance

Poredoš¹,

Ježovnik²

2013

JAT

107

109

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Endothelial dysfunction as an integrating index of the risk factor burden and genetic susceptibility is an early marker of atherothrombotic disease. Therefore, tremendous interest exists in its measurement and determination of the clinical utility of the evaluation of endothelial function. Different invasive and non-invasive techniques exist for exploring various aspects of the pathobiology of the endothelium. As endothelial dysfunction is a diffuse-systemic disorder, the peripheral arteries, because of their accessibility, represent the basis for assessment of endothelial dysfunction.

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Section: Peripheral Arterial Tonometrymentioning

confidence: 99%

Testing Endothelial Function and its Clinical Relevance

Poredoš¹,

Ježovnik²

2013

JAT

107

109

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show abstract

“…Exercise testing should be symptomlimited and careful electrocardiographic and blood pressure monitoring should be performed during both the test and the recovery phase as syncope can occur during or immediately after exercise [224][225][226][227][228][229][230][231][232][233][234][235][236] . These two situations should be considered separately.…”

Section: Exercise Testingmentioning

confidence: 99%

Guidelines on management (diagnosis and treatment) of syncope

Brignole¹,

Alboni²,

Benditt

et al. 2001

European Heart Journal

680

432

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“…tion in response to stimuli such as physical and mental stress, 23,26 exercise, 27 and biochemicals, including adrenergic agents. 28 Venoconstriction to adrenergic stimulation is regional; thus, there is excellent evidence dating to Donegan's work 29 on human splanchnic and cutaneous venoconstriction in response to sympathetic stimulation, but there is less evidence for the response of other venous beds.…”

Section: When Does Venoconstriction Usually Occur?mentioning

confidence: 99%

Pooling in Chronic Orthostatic Intolerance

Stewart

2002

Circulation

121

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Background-Orthostatic intolerance is characterized by postural tachycardia syndrome (POTS) with exaggerated tachycardia, orthostatic symptoms, and "pooling" (which comprises acrocyanosis and dependent edema when upright). My colleagues and I tested the hypothesis that pooling results from increased venous compliance in POTS patients. Methods and Results-Fifteen patients aged 13 to 19 years were compared with 11 healthy, age-matched controls. The POTS group was divided into patients with high venous pressure (P v Ͼ20 mm Hg) and normal P v on the basis of resting supine P v obtained in previous work. Subjects were studied using strain gauge plethysmography to measure blood flow, P v , and the venous compliance volume-pressure relation while supine and during incremental head-up tilt testing at Ϫ10°, 0°, 20°, and 35°. Volume-pressure relations of controls and POTS patients with normal P v and high P v were not different and were unchanged by orthostasis. Supine leg peripheral resistance was greater than control resistance in patients with high P v (54Ϯ9 versus 30Ϯ6 mm Hg · mL -1 · 100 mL -1 · min -1 ) and less than control resistance in patients with normal P v (17Ϯ2 mm Hg · mL -1 · 100 mL -1 · min -1 ). On upright tilt, resistance decreased in high P v to approximate resistance in normal P v . Resistance in controls increased throughout tilt. Leg P v increased in patients with normal P v and in controls but remained unchanged in the high P v group. Conclusions-The findings suggest that pooling in POTS is due to blunted arterial vasoconstriction, which produces passive redistribution of blood within peripheral venous capacitance beds. Venous compliance in POTS is similar to that in control subjects.

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Failure of Reflex Venoconstriction During Exercise in Patients With Vasovagal Syncope

Abstract: Patients with vasovagal syncope exhibit a failure of the normal increase in tone in the splenic capacitance bed and in forearm resistance vessels during dynamic exercise. Forearm venous tone increases normally during lower-body negative pressure.

Cited by 68 publications

References 23 publications

Testing Endothelial Function and its Clinical Relevance

Testing Endothelial Function and its Clinical Relevance

Guidelines on management (diagnosis and treatment) of syncope

Pooling in Chronic Orthostatic Intolerance

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