Knowra Vasovagal syncope Vasovagal syncope Vasovagal syncope is a brief loss of consciousness caused by a reflex that lowers blood pressure, heart rate, or both, reducing blood flow to the brain. Consciousness usually returns spontaneously when cerebral blood flow is restored.
Vasovagal reflex : A reflex that increases vagal activity and reduces sympathetic activity, slowing the heart and widening blood vessels. This autonomic shift produces the cardiovascular changes that cause the faint.
Prodrome (medicine) : Early symptoms that precede a disease episode or other clinical event. Warmth, nausea, sweating, or visual dimming can precede a vasovagal faint.
Carotid sinus syndrome : A reflex disorder in which stimulation of the carotid sinus causes an abnormal fall in heart rate or blood pressure. It is another reflex cause of syncope, often associated with neck movement or pressure.
Autonomic nervous system : The nervous system division that regulates involuntary functions such as heart rate, blood pressure, and digestion. Vasovagal syncope arises from a transient autonomic reflex.
Emotional stress : A psychological or physiological response to perceived demands or threats. Acute emotional distress can trigger a vasovagal episode.
Orthostatic hypotension : A sustained fall in blood pressure after standing, caused by impaired compensation for gravity. It can also cause fainting, but does not require the vasovagal reflex.
Tilt table test : A test that monitors cardiovascular responses as a person is moved from lying to an upright position. It can reproduce symptoms and help evaluate suspected reflex syncope.
Situational syncope : Reflex syncope linked to specific actions such as coughing, swallowing, or urination. Its episodes are tied to particular bodily actions rather than the broader trigger pattern of vasovagal syncope.
Blood pressure : The force exerted by circulating blood against the walls of blood vessels. A sudden fall can reduce the brain's blood supply and contribute to loss of consciousness.
Pain : An unpleasant sensory and emotional experience associated with actual or potential tissue damage. Sudden pain is a recognized trigger for reflex fainting.
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