title: Tilt angles and positive response of head-up tilt test in children with orthostatic intolerance.
abstract: This study aimed at examining three tilt angle-based positive responses and the time to positive response in a head-up tilt test for children with orthostatic intolerance, and the psychological fear experienced at the three angles during head-up tilt test. A total of 174 children, including 76 boys and 98 girls, aged from 4 to 18 years old (mean 11.3±2.8 years old), with unexplained syncope, were randomly divided into three groups, to undergo head-up tilt test at the angles of 60°, 70° and 80°, respectively. The diagnostic rates and times were analysed, and Wong-Baker face pain rating scale was used to access the children's psychological fear. There were no significant differences in diagnostic rates of postural orthostatic tachycardia syndrome and vasovagal syncope at different tilt angles during the head-up tilt test (p>0.05). There was a significant difference, however, in the psychological fear at different tilt angles utilising the Kruskal-Wallis test (χ2=36.398, p<0.01). It was mildest at tilt angle 60° utilising the Kolmogorov-Smirnov test (p<0.01). A positive rank correlation was found between the psychological fear and the degree of tilt angle (r(s)=0.445, p<0.01). Positive response appearance time was 15.1±14.0 minutes at 60° for vasovagal syncope children. There was no significant difference in the time to positive response, at different tilt angles during the head-up tilt test for vasovagal syncope or for postural orthostatic tachycardia syndrome. Hence, it is suggested that a tilt angle of 60° and head-up tilt test time of 45 minutes should be suitable for children with vasovagal syncope.
authors.affiliation: 1Department of Pediatrics,Peking University First Hospital,Beijing,China.
authors.forename: Jing
authors.initials: J
authors.lastname: Lin
authors.affiliation: 1Department of Pediatrics,Peking University First Hospital,Beijing,China.
authors.forename: Yuli
authors.initials: Y
authors.lastname: Wang
authors.affiliation: 2Department of Pediatrics,Northwestern Feinberg School of Medicine,Chicago,Illinois,United States of America.
authors.forename: Todd
authors.initials: T
authors.lastname: Ochs
authors.affiliation: 3Department of Physiology and Pathophysiology,Peking University Health Science Center,Beijing,China.
authors.forename: Chaoshu
authors.initials: C
authors.lastname: Tang
authors.affiliation: 1Department of Pediatrics,Peking University First Hospital,Beijing,China.
authors.forename: Junbao
authors.initials: J
authors.lastname: Du
authors.affiliation: 1Department of Pediatrics,Peking University First Hospital,Beijing,China.
authors.forename: Hongfang
authors.initials: H
authors.lastname: Jin
mesh_terms: D000293:Adolescent; D001794:Blood Pressure / Q000502:physiology*; D002648:Child; D002675:Child, Preschool; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D054971:Orthostatic Intolerance / Q000150:complications / Q000175:diagnosis / Q000503:physiopathology*; D054972:Postural Orthostatic Tachycardia Syndrome / Q000175:diagnosis / Q000209:etiology* / Q000503:physiopathology; D011187:Posture / Q000502:physiology*; D012189:Retrospective Studies; D018667:Tilt-Table Test / Q000379:methods*