Overview Vasovagal syncope (also called neurocardiogenic syncope) is a temporary loss of consciousness caused by a neurological reflex that produces either sudden dilation of the blood vessels in the legs, or a very slow heart rate (bradycardia), or both. 2  Vasovagal syncope accounts for more than half of all episodes of syncope.

https://www.verywellhealth.com/vasovagal-cardioneurogenic-syncope-1746389