vasovagal syncope

(redirected from Vagal response)
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Related to Vagal response: vagus nerve, Vagal episode, Vasovagal Syndrome

syncope

 [sing´kah-pe]
faint. adj. adj syn´copal, syncop´ic.
cardiac syncope sudden loss of consciousness, either with momentary premonitory symptoms or without warning, due to cerebral anemia caused by ventricular asystole, extreme bradycardia, or ventricular fibrillation.
laryngeal syncope tussive syncope.
neurocardiogenic syncope a particularly serious type of vasovagal attack; the etiology is unknown.
stretching syncope syncope associated with stretching the arms upward with the spine extended.
swallow syncope syncope associated with swallowing, a disorder of atrioventricular conduction mediated by the vagus nerve.
tussive syncope brief loss of consciousness associated with paroxysms of coughing.
vasovagal syncope vasovagal attack.

va·so·de·pres·sor syn·co·pe

faintness or loss of consciousness due to reflex reduction in blood pressure.
Synonym(s): vasovagal syncope

neurocardiogenic syncope

A syncope with a psychogenic substrate and predisposition to bradycardia, hypotension and peripheral vasodilation.
 
Clinical findings
Abrupt loss of vascular tone; nausea; diaphoresis; pallor.
 
Diagnosis
Tilt test, in which the patient is placed on a tilt table at a 40º to 80º angle from horizontal and maintained in a motionless upright position for 10–15 minutes or more.
 
Management
Beta blockers—e.g., metoprolol, theophylline, disopyramide.

Mechanism
Uncertain; probably activation of myocardial mechanoreceptors (C fibres), with decreased efferent sympathetic tone and increased efferent parasympathetic tone.

vasovagal syncope

Neurocardiogenic syncope, see there.

va·so·va·gal syn·co·pe

(vā'sō-vā'găl sing'kŏ-pē)
Faintness or loss of consciousness due to increased vagus nerve (parasympathetic) activity.
Synonym(s): vasodepressor syncope.

vasovagal syncope

See FAINTING.
References in periodicals archive ?
At CTP Time 1 (vagal response), 49 percent (n = 25) correctly identified the patient as having a vasovagal episode due to straining for a bowel movement; 51 percent in = 26) provided incorrect answers.
The heart rate decreased gradually with voltage increased from 1 to 4V, while the heart rate will not be reduced any more once the maximal vagal response reached by 4v stimulating.
The activation sequence and electrical conduction between LA and LSPV with vagal response
The heart rate, the ERP, heterogeneity and inducibility of AF with vagal response. Several clinical observations have suggested that an increased parasympathetic tone is involved in the genesis of at least some forms of paroxysmal AF (9).
In our study, with vagal response simultaneously, we delivered electronic stimulation at dog's cervical vagal trunk and paced at HRA, LAA, PV-LAJ, LSPVm and LSPVd sites, the heart rate was reduced (from 156 [+ or -] 34 bpm to 75 [+ or -] 34 bpm, on average), the ERP in HRA, LAA, PV-LAJ, LSPVm and LSPVd sites was significantly shorted (from 112.8 [+ or -] 11.2 ms to 92.6 [+ or -] 12.4 ms, on average), and the ERP heterogeneity (COV-ERP) was increased (from 30 [+ or -] 1% to 3 [+ or -] 3% on average) in almost all 12 dogs.
Vagal response could be made easily by stimulating dog's cervical vagal trunk and the effect on heart lasted more than 10 hours in our study.
The LSPVd with less vagal response and lower inducibility of AF than the other sites, this might be the point that contributes to the increased ERP heterogeneity, and we may need to do further investigation in difference of vagal never distribution between LA, PV and within PV.
The conduction between left superior pulmonary vein and left atria with vagal response. Almost 25% paroxysmal AF will develop to chronic AF eventually.
When humans and other mammals are confined or cannot fight or flee during times of danger, the nervous system reverts to the unmyelinated vagal response. Mice caught by a predator, for example, will lose consciousness; the unmyelinated vagal response to being captured allows the animal to escape the pain and trauma of its situation.
Porges also recommends using higher-pitched vocal music to encourage a vagal response that is open to social engagement.
In other words, the higher the parasympathetic modulation at rest before the stressor, the greater the vagal response. In the present study, the greatest change in [LF.sub.nu] and [HF.sub.nu] during UP might be related to the higher resting [HF.sub.nu] values, which indicates a good adaptability to orthostatic stress.
One possible explanation may be that we administered local anesthesia rather than general anesthesia, which could lead to vagal responses because of pain during the procedure.