title: Reassessing Risk Factors in Pediatric Patients With Pacemakers Implanted for Atrioventricular Block: The Impact of Nonsustained Ventricular Tachycardia.
abstract: BACKGROUND
  In pediatric patients with pacemakers implanted for atrioventricular block (AVB), nonsustained ventricular tachycardia (NSVT) detected during routine surveillance is a finding of unknown significance. We sought to describe the incidence of NSVT and determine if there was an association between NSVT and adverse outcomes in these patients.
  
  
  RESULTS
  This is a single-center retrospective study of 136 patients (1971-2013) with pacemakers implanted for advanced and complete AVB.
  
  
  METHODS
  structural heart disease, diagnoses of myocarditis, cardiomyopathy or channelopathy preceding AVB diagnosis, and sustained or polymorphic ventricular tachycardia (VT) as the first occurring arrhythmia after pacemaker implant. During median follow-up of 11.6 years (IQR 4.3 years, 17 years), 14 (10%) patients had NSVT. There were 6 (4.4%) deaths. Overall, Kaplan-Meier 20-year survival from time of implant was 93%. By univariate analysis, earlier mortality was associated with NSVT (P = 0.010), sustained left ventricular (LV) dysfunction (P = 0.004), maternal autoantibodies (P = 0.017), and acquired AVB (P = 0.049). By multivariate analysis, earlier mortality was associated with NSVT (HR: 5.39 [95% CI: 1.02-28.41]; P = 0.047) and sustained LV dysfunction (HR: 10.24 [95% CI: 1.83-57.32]; P = 0.008).
  
  
  CONCLUSIONS
  In children with pacemakers implanted for AVB, NSVT is not uncommon and may be associated with increased mortality. Persistent LV dysfunction may also be a potential factor associated with death. Closer follow-up should be considered in patients with these findings. Large, multicenter studies should be considered to confirm these findings and identify risk stratification methods for this unique patient population.
authors.affiliation: Lillie Frank Abercrombie Section of Pediatric Cardiology, Texas Children's Hospital, Baylor College of Medicine Houston, Texas, USA.|Oklahoma Children's Heart Center, Oklahoma University Health Sciences Center, Oklahoma City, Oklahoma, USA.
authors.forename: Mary C
authors.initials: MC
authors.lastname: Niu
authors.affiliation: Lillie Frank Abercrombie Section of Pediatric Cardiology, Texas Children's Hospital, Baylor College of Medicine Houston, Texas, USA.
authors.forename: Shaine A
authors.initials: SA
authors.lastname: Morris
authors.affiliation: Lillie Frank Abercrombie Section of Pediatric Cardiology, Texas Children's Hospital, Baylor College of Medicine Houston, Texas, USA.
authors.forename: Michele
authors.initials: M
authors.lastname: Krenek
authors.affiliation: Lillie Frank Abercrombie Section of Pediatric Cardiology, Texas Children's Hospital, Baylor College of Medicine Houston, Texas, USA.
authors.forename: Caridad M
authors.initials: CM
authors.lastname: DE LA Uz
authors.affiliation: Center for Clinical Research and Evidence-Based Medicine, Department of Pediatrics, University of Texas Health Science Center at Houston, Houston, Texas, USA.
authors.forename: Claudia
authors.initials: C
authors.lastname: Pedroza
authors.affiliation: Lillie Frank Abercrombie Section of Pediatric Cardiology, Texas Children's Hospital, Baylor College of Medicine Houston, Texas, USA.
authors.forename: Christina Y
authors.initials: CY
authors.lastname: Miyake
authors.affiliation: Lillie Frank Abercrombie Section of Pediatric Cardiology, Texas Children's Hospital, Baylor College of Medicine Houston, Texas, USA.
authors.forename: Jeffrey J
authors.initials: JJ
authors.lastname: Kim
authors.affiliation: Lillie Frank Abercrombie Section of Pediatric Cardiology, Texas Children's Hospital, Baylor College of Medicine Houston, Texas, USA.
authors.forename: Santiago O
authors.initials: SO
authors.lastname: Valdés
mesh_terms: D000293:Adolescent; D017677:Age Distribution; D054537:Atrioventricular Block / Q000401:mortality* / Q000517:prevention & control*; D015984:Causality; D002648:Child; D015897:Comorbidity; D005260:Female; D006801:Humans; D015994:Incidence; D008137:Longitudinal Studies; D008297:Male; D010138:Pacemaker, Artificial / Q000706:statistics & numerical data*; D019736:Prostheses and Implants / Q000706:statistics & numerical data*; D012189:Retrospective Studies; D012307:Risk Factors; D017678:Sex Distribution; D015996:Survival Rate; D017180:Tachycardia, Ventricular / Q000401:mortality*; D013781:Texas / Q000453:epidemiology; D016896:Treatment Outcome
keywords: LV dysfunction; complete atrioventricular block; mortality; nonsustained ventricular tachycardia; pacing; sudden death