To evaluate the indications, underlying cardiac disorders, efficacy and complications involved with implantable cardioverter- defibrillators (ICDs) in paediatric patients in The Netherlands, the records of all patients aged 18 years or younger who underwent ICD placement were reviewed retrospectively. Between January 1995 and September 2002, 23 patients (11 males, 12 females; median age 12 years, range 6 months to 16 years) underwent ICD implantation. The ICD was implanted for aborted sudden cardiac death ( n =14), syncope ( n =5) or for primary prevention of sudden cardiac death ( n =4). Underlying cardiac disorders were electrical diseases ( n =16), hypertrophic or dilated cardiomyopathy ( n =4) and congenital cardiac malformations ( n =3). Five patients had an epicardially placed ICD, while 18 underwent a transvenous approach. The generator was placed in an abdominal position in eight patients, whereas it was placed in the subpectoral region in 15. There was no early mortality. Median hospital stay was 5 days (range 2- 30 days). Median follow-up time was 29 months (range 1 month to 7 years). Seven patients experienced an inappropriate shock after a median period of 7 months; five patients an appropriate shock after a median period of 3 months. The reasons for inappropriate shock were supraventricular tachycardia ( n =1), sinus tachycardia ( n =4) or T-wave sensing ( n =2). One patient with malignant long QT syndrome died of intractable arrhythmias and irreversible cardiomyopathy. Generator replacement was necessary in four patients after 28, 44, 51 and 54 months respectively. Conclusion:Implantable cardioverter-defibrillator implantation in paediatric patients is a safe procedure with a good medium-term outcome. The most serious problem is the occurrence of a significant number of inappropriate shocks. To evaluate the indications, underlying cardiac disorders, efficacy and complications involved with implantable cardioverter-defibrillators (ICDs) in pediatric patients in The Netherlands, the records of all patients aged 18 years or younger who underwent ICD placement were retrospectively reviewed. Between January 1995 and September 2002, 23 patients (11 males, 12 females; median age 12 years, range 6 months to 16 years) underwent ICD implantation. The ICD was implanted for aborted sudden cardiac death (n = 14), syncope for primary prevention of sudden cardiac death (n = 4). Underlying cardiac disorders were electrical diseases (n = 16), hypertrophic or dilated cardiomyopathy (n = 4) and congenital cardiac malformations ICD, while 18 underwent a transvenous approach. The generator was placed in an abdominal position in eight patients, but it was placed in the subpectoral region in 15. There was no early mortality. Median follow-up time was 29 months (range 1 month to 7 years). Seven patients experienced an inappropriate shock after a median period of 7 months; five patients an appropriate shock After a median period of 3 months. The reasons for inappropriate shock were supraventricular tachycardia (n = 1), sinus tachycardia (n = 4) or T-wave sensing Arrhythmias and irreversible cardiomyopathy. Generator replacement was necessary in four patients after 28, 44, 51 and 54 months respectively. Conclusion: Implantable cardioverter-defibrillator implantation in pediatric patients is a safe procedure with a good medium-term outcome. The most serious problem is the occurrence of a significant number of inappropriate shocks.