Neurocardiology. Neurogenic syncope.

Neurogenic syncope is one of the most frequent causes of recurrent syncope in patients with structurally normal heart. The mechanisms leading to neurogenic syncope remain poorly understood. Evidence recently obtained from several laboratories suggests that impaired arterial baroreflex adaptation to orthostatic stress, in addition to cessation of vasoconstrictive sympathetic traffic, contributes to the development of hypotension and bradycardia that determine the vasovagal response. Neurogenic syncope encompasses a wide range of reflexogenic syncope that includes the vasovagal type, micturition syncope, carotid sinus hypersensitivity and post-prandial syncope. Head-up tilt testing has become the diagnostic tool of choice for the evaluation of patients with recurrent neurogenic syncope, providing an acceptable sensitivity and high specificity that is largely dependent on the type of tilt protocol used to induce neurogenic syncope. This chapter will review the pathophysiology, diagnosis and therapeutic approach to the patient with neurogenic syncope.