Utility of routine follow-up defibrillator threshold testing in congenital heart disease and pediatric populations.
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.
Stephenson
Elizabeth A
EA
Department of Cardiology, Children's Hospital, Boston, Boston, Massachusetts 02115, USA.
Cecchin
Frank
F
Walsh
Edward P
EP
Berul
Charles I
CI
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