title: Clinical experience of entirely subcutaneous implantable cardioverter-defibrillators in children and adults: cause for caution.
abstract: OBJECTIVE
  This paper describes our clinical experience of using an entirely subcutaneous implantable cardioverter-defibrillator (S-ICD) in children and adults. Maintaining lead integrity and long-term vascular access are critical challenges of ICD therapy, especially in younger patients. The S-ICD has considerable theoretical advantages in selected patients without pacing indications, particularly children and young adults. Although sensing in an S-ICD may be influenced by age, pathology, and posture, there are currently few published data on clinical sensing performance outside the setting of intra-operative testing or in younger patients.
  
  
  RESULTS
  Patients were selected by a multi-disciplinary team on clinical grounds for S-ICD implantation from a broad population at risk of sudden arrhythmic death. Sixteen patients underwent implantation [median age 20 years (range 10-48 years)]. Twelve had primary electrical disease and four had congenital structural heart disease. There were no operative complications, and ventricular fibrillation (VF) induction testing was successful in all cases. During median follow-up of 9 months (range 3-15 months), three children required re-operation. Eighteen clinical shocks were delivered in six patients. Ten shocks in four patients were inappropriate due to T-wave over-sensing. Within the eight shocks for ventricular arrhythmia, three were delivered for VF, among which two had delays in detection with time to therapy of 24 and 27 s.
  
  
  CONCLUSIONS
  The S-ICD is an important new option for some patients. However, these data give cause for caution in light of the limited published data regarding clinical sensing capabilities, particularly among younger patients.
authors.affiliation: Department of Cardiology, Royal Brompton Hospital, Sydney Street, London, UK.
authors.forename: Julian W E
authors.initials: JW
authors.lastname: Jarman
authors.forename: Karen
authors.initials: K
authors.lastname: Lascelles
authors.forename: Tom
authors.initials: T
authors.lastname: Wong
authors.forename: Vias
authors.initials: V
authors.lastname: Markides
authors.forename: Jonathan R
authors.initials: JR
authors.lastname: Clague
authors.forename: Janice
authors.initials: J
authors.lastname: Till
mesh_terms: D000293:Adolescent; D000328:Adult; D001145:Arrhythmias, Cardiac / Q000628:therapy*; D016022:Case-Control Studies; D002648:Child; D016757:Death, Sudden, Cardiac / Q000517:prevention & control*; D017147:Defibrillators, Implantable; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D016896:Treatment Outcome; D055815:Young Adult