منابع مشابه
An Experimental Model of Vasovagal Syncope Induces Cerebral Hypoperfusion and Fainting-Like Behavior in Awake Rats
Vasovagal syncope, a contributing factor to elderly falls, is the transient loss of consciousness caused by decreased cerebral perfusion. Vasovagal syncope is characterized by hypotension, bradycardia, and reduced cerebral blood flow, resulting in fatigue, altered coordination, and fainting. The purpose of this study is to develop an animal model which is similar to human vasovagal syncope and ...
متن کاملOrthostatic Cerebral Hypoperfusion Syndrome
OBJECTIVE Orthostatic dizziness without orthostatic hypotension is common but underlying pathophysiology is poorly understood. This study describes orthostatic cerebral hypoperfusion syndrome (OCHOs). OCHOs is defined by (1) abnormal orthostatic drop of cerebral blood flow velocity (CBFv) during the tilt test and (2) absence of orthostatic hypotension, arrhythmia, vascular abnormalities, or oth...
متن کاملSyncope, cerebral perfusion, and oxygenation.
During standing, both the position of the cerebral circulation and the reductions in mean arterial pressure (MAP) and cardiac output challenge cerebral autoregulatory (CA) mechanisms. Syncope is most often associated with the upright position and can be provoked by any condition that jeopardizes cerebral blood flow (CBF) and regional cerebral tissue oxygenation (cO(2)Hb). Reflex (vasovagal) res...
متن کاملHyperventilation, cerebral perfusion, and syncope.
This review summarizes evidence in humans for an association between hyperventilation (HV)-induced hypocapnia and a reduction in cerebral perfusion leading to syncope defined as transient loss of consciousness (TLOC). The cerebral vasculature is sensitive to changes in both the arterial carbon dioxide (PaCO2) and oxygen (PaO2) partial pressures so that hypercapnia/hypoxia increases and hypocapn...
متن کاملHypocapnia and cerebral hypoperfusion in orthostatic intolerance.
BACKGROUND AND PURPOSE Orthostatic and other stresses trigger tachycardia associated with symptoms of tremulousness, shortness of breath, dizziness, blurred vision, and, often, syncope. It has been suggested that paradoxical cerebral vasoconstriction during head-up tilt might be present in patients with orthostatic intolerance. We chose to study middle cerebral artery (MCA) blood flow velocity ...
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ژورنال
عنوان ژورنال: Neurology
سال: 2003
ISSN: 0028-3878,1526-632X
DOI: 10.1212/01.wnl.0000068018.95076.c0