Cerebral oxygenation in children with syncope during head-upright tilt test.

The pathophysiology of neurocardiogenic syncope remains incompletely known. In this entity, besides abnormal systemic hemodynamic regulation, potential cerebral circulatory abnormalities have been reported. In this setting, cerebral saturation assessment could detect cerebral blood flow changes and estimate the sufficiency of brain oxygenation during the event. A head-upright tilt test was performed in 25 children aged between 6 and 16 years. In addition to the standard protocol, cerebral oxygen saturation was determined noninvasively by means of a near-infrared spectrophotometry device. In the 19 children with a positive tilt test, significant impairment of cerebral saturation was detected both at the start of the patient's complaints (without hemodynamic modifications) and during syncope. Our results support the hypothesis of the presence of abnormal cerebral hemodynamic autoregulation in children with neurocardiogenic syncope.