Head-upright tilt table testing for recurrent, unexplained syncope.

Recurrent episodes of unexplained syncope are a common and often frustrating problem for the practicing physician. Although vasovagally mediated episodes of hypotension and bradycardia have been felt to be a common cause of these idiopathic events, traditionally this was a diagnosis of exclusion. Recently, head-upright tilt table testing has emerged as a method both for confirming the diagnosis of vasovagal syncope and for better understanding the mechanisms by which these events occur. This paper reviews current understanding of the pathophysiology of vasovagal syncope, the development and role of head-upright tilt table testing in its evaluation, and potential therapeutic modalities that can be helpful for the prevention of recurrent episodes.