Variations in expression and treatment of transient neurocardiogenic instability.

Whereas previous reports describe the head-up tilt test for the diagnosis of neurocardiogenic syncope, this study focuses on the events leading up to syncope. These events are part of a spectrum of neurocardiogenic instability; syncope is the extreme end point. This report is based on tilt studies of 108 patients, aged 4 to 22 years (mean 13), with histories of either unexplained syncope or episodes of visual blackout without loss of consciousness.