vasovagal reflex


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Related to vasovagal reflex: vasovagal syncope, Vagovagal reflex

vasovagal reflex

a stimulation of the vagus nerve by reflex in which irritation of the larynx or the trachea results in slowing of the pulse rate.
References in periodicals archive ?
In the author's experience with over 50 patients with needle phobia, and in all similar cases reported in the medical literature, those afflicted inevitably display symptoms of an autonomic vasovagal reflex whenever they undergo a needle procedure.
The vasovagal reflex in needle phobia may include virtually any type and combination of autonomic symptoms, eg, a clammy diaphoresis, pallor, nausea, respiratory disturbances, and various levels of unresponsiveness.
In several case reports, ECG changes during the vasovagal reflex among patients with needle phobia have included sinus arrhythmia, premature atrial contractions, premature junctional contractions, unifocal and multifocal premature ventricular contractions, bigeminy, first- and second-degree block, changes in P waves, ST waves, and T waves, sinus bradycardia, sinus tachycardia, ventricular tachycardia, ventricular fibrillation, and asystole.
Probably because the pituitary perceives a reduced intravascular volume during vasovagal shock, vasopressin or antidiuretic hormone (ADH) rises in the vasovagal reflex with venipuncture,(1)(2)(45) as does endothelin.
Both the vasovagal reflex and needle phobia strongly tend to run in families.
A vasovagal reflex has been found in all patients with needle phobia tested so far, and the medical histories of most of them include an adverse learning experience that triggered the needle fear.
Blood-injury phobia, which is often linked with needle phobia,(3) probably often arises when a patient with a strong vasovagal reflex undergoes a needle procedure or has an accident that results in a vasovagal response.
Over the 4+ million years of human evolution, surely many genes controlling blood pressure, pulse, cardiac rhythm, and stress hormone release were selected for to create the vasovagal reflex.