title: Analysis of P wave and P dispersion in children with secundum atrial septal defect.
abstract: BACKGROUND
  P maximum and P dispersion are evaluated as predictors of paroxysmal atrial fibrillation in adults. In this study, these variables are being investigated in children with secundum ASD in comparison with that of normal controls and in relation to size of ASD and the presence or absence of atrial dilation.
  
  
  METHODS
  Ninety-four children with isolated secundum ASD (33 boys, 60 girls; mean +/- SD age at diagnosis 2.9 +/- 4.1 years) and 65 age-matched controls (mean +/- SD age 4.2 +/- 4.2 years) were evaluated. Resting 12-lead ECG was used to measure P waves from which P maximum and P dispersion (difference between maximum and minimum P-wave duration) were derived. ASD children were arbitrarily subgrouped according to ASD sizes (small: 1-3 mm, moderate: 4-7 mm, large: > or = 8 mm). The presence of right atrial dilation was noted from echocardiography.
  
  
  RESULTS
  Children with ASD had significantly longer mean P dispersion compared to controls (P dispersion: 30.2 +/- 11.1 vs 26.4 +/- 6.6 ms, P = 0.008). Mean P maximum and P dispersion were significantly prolonged with increasing ASD size (P < 0.001). Children with right atrial dilation had significantly longer P maximum (102.3 +/- 15.2 vs 82.8 +/- 13.4 ms, P < 0.001) and larger P dispersion (36.1 +/- 12.5 vs 27.6 +/- 9.4 ms, P = 0.003) compared to those without right atrial dilation.
  
  
  CONCLUSIONS
  Prolonged atrial conduction time and inhomogeneity of atrial conduction may possibly be present in children with moderate to large sized ASD and in those with atrial dilation.
authors.affiliation: Department of Physiology, Faculty of Medicine, National University of Singapore, 2 Medical Drive, Singapore 117597, Republic of Singapore. phshotf@nus.edu.sg
authors.forename: T F
authors.initials: TF
authors.lastname: Ho
authors.forename: E L
authors.initials: EL
authors.lastname: Chia
authors.forename: W C
authors.initials: WC
authors.lastname: Yip
authors.forename: K Y
authors.initials: KY
authors.lastname: Chan
mesh_terms: D000704:Analysis of Variance; D001281:Atrial Fibrillation / Q000175:diagnosis / Q000503:physiopathology; D002675:Child, Preschool; D004562:Electrocardiography; D005260:Female; D006344:Heart Septal Defects, Atrial / Q000473:pathology / Q000503:physiopathology*; D006801:Humans; D008297:Male