What is the pathophysiology of syncope?

Decr brain bloodflow: Syncope (loss of consciousness) is caused by reduced blood flow to the brain. Most cases are cardiogenic in nature (for example, arrhythmias), but other causes can include vasovagal response, carotid artery compression, vertebrobasilar system disease, etc. See your primary care provider for further discussion if you've experienced syncope. http://www.ninds.nih.gov/disorders/syncope/syncope.htm