Head-up tilt test in the evaluation of unexplained syncope: Are there any differences between children and adults?

Background and objectives. Little is known about the differences between ch ildren and adults in the results af head-up tilt test. This study sought to investigate the potential differences concerning: a) the clinical profile and circumstances of spontaneous syncope; b) the overall diagnostic perform ance of the test, and c) the type of positive response obtained. Material and methods. We studied 31 children and 123 adults with unexplaine d syncope. If baseline test (tilting 70 degrees for 30 min) resulted negati ve, it was repeated under isoprenaline low-dose infusion. Results. There were no differences in either clinical profile, except for s evere traumatism more frequent in adults (25% vs. 3% in children; p < 0.05) , or overall diagnostic performance (39% in children vs. 33% in adults; p = NS). However, the way the test rendered positive (via basal tilting in 92% of children vs. 50% in adults; p < 0.05) and the rate of cardioinhibitory response (42% in children vs 8% in adults; p < 0.01) were significantly dif ferent. Conclusion. In this study children, in contrast to adults, rarely have a po sitive response in tilting under isoprenaline infusion. They also present a much higher rate of cardio-inhibitory response than adults.