title: Utility of routine follow-up defibrillator threshold testing in congenital heart disease and pediatric populations.
abstract: BACKGROUND
  Recent studies have suggested that routine defibrillation threshold (DFT) testing of implantable cardioverter defibrillators (ICDs) in adults may not be necessary. The congenital heart disease and pediatric populations are a unique group of ICD recipients having a higher incidence of lead failure. We investigated the utility of follow-up DFT testing in this population.
  
  
  RESULTS
  The records of 155 ICD recipients at one center were retrospectively reviewed, and patients having one or more follow-up DFT tests were analyzed. The patients were divided into two groups. The "routine" group consisted of 58 follow-up DFT procedures in 46 patients, without known changes in ICD parameters. The "prompted" group consisted of 21 follow-up DFT procedures in 18 patients, motivated by clinical concerns about changes in ICD lead status. Of 58 "routine" DFTs performed at a mean postimplant duration of 32 +/- 23 months (range 2-78), 7 (12%) had reprogramming, and 1 required a hardware change as a result of the testing. Of the 21 "prompted" DFTs performed, 7 required device reprogramming, and 3 required hardware upgrade. Overall, 19 (24%) of 79 procedures detected clinically significant changes, requiring reprogramming or ICD system revision. No complications were seen from follow-up DFT testing.
  
  
  CONCLUSIONS
  A high rate of abnormalities was found at follow-up DFT testing in this population, especially in the group of patients with clinically prompted testing. Clinically indicated DFT testing, as expected, has a high yield of important information on device function in congenital heart disease and pediatric populations.
authors.affiliation: Department of Cardiology, Children's Hospital, Boston, Boston, Massachusetts 02115, USA.
authors.forename: Elizabeth A
authors.initials: EA
authors.lastname: Stephenson
authors.forename: Frank
authors.initials: F
authors.lastname: Cecchin
authors.forename: Edward P
authors.initials: EP
authors.lastname: Walsh
authors.forename: Charles I
authors.initials: CI
authors.lastname: Berul
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D017147:Defibrillators, Implantable / Q000706:statistics & numerical data*; D004554:Electric Countershock / Q000295:instrumentation / Q000706:statistics & numerical data; D004868:Equipment Failure / Q000706:statistics & numerical data*; D019544:Equipment Failure Analysis / Q000379:methods*; D005260:Female; D005500:Follow-Up Studies; D006330:Heart Defects, Congenital / Q000453:epidemiology* / Q000628:therapy*; D006801:Humans; D015994:Incidence; D008297:Male; D011379:Prognosis; D012189:Retrospective Studies; D018570:Risk Assessment / Q000379:methods*; D012307:Risk Factors; D014481:United States / Q000453:epidemiology