Distribution of syncopal episodes in children and adolescents with neurally mediated cardiac syncope through the day

Aims To assess the relation between the timing of syncopal attacks and tilt test positivity. Method and results Prospective comparisons of distribution of syncopal attacks in 49 consecutive neurally mediated cardiac syncope (NMCS) patients (19 boys, 30 girls, mean age 13.7 +/- 0.68) were evaluated. Head-up tilt test (HUT) was positive in 28 patients and negative in 21. A questionnaire was given to every patient about the time and number of the syncopal attacks, presyncopal symptoms or signs before HUT. Although syncopal attacks were found to be concentrated in the morning especially between 10 AM and 12 noon in HUT positive patients (P < 0.001), there was a concentration in the late afternoon and evening period of the day especially between 2 PM and 6 PM in HUT negative patients (P < 0.001). Conclusion It was assumed that diurnal variation in autonomic function may be the factor in the timing of syncopal events during morning hours in the HUT positive NMCS children and adolescents. (c) 2005 Published by Elsevier Ltd on behalf of The European Society of Cardiology.