title: Outcomes of defibrillator therapy in catecholaminergic polymorphic ventricular tachycardia.
abstract: BACKGROUND
  Catecholaminergic polymorphic ventricular tachycardia (CPVT) is an inherited arrhythmia syndrome characterized by adrenergically induced ventricular arrhythmias in patients with structurally normal hearts. Initiating triggered arrhythmias, such as bidirectional ventricular tachycardia, often degenerate into reentrant arrhythmias, such as ventricular fibrillation (VF).
  
  
  OBJECTIVE
  To determine whether the effectiveness of implantable cardioverter-defibrillator (ICD) shocks is dependent on rhythm type.
  
  
  METHODS
  It is a retrospective study of patients with CPVT who had undergone ICD implantation. Thirteen patients received ICDs (median age 15 years; range 9-43 years): 7 of 13 (54%) for cardiac arrest and 6 of 13 (46%) for syncope despite drug therapy. The median follow-up duration was 4.0 years (range 1.7-19.9 years). Nineteen reinterventions occurred, excluding generator replacements. Ten patients received 96 shocks (median 4 shocks; range 1-30 shocks). Eighty-seven shock electrograms were reviewed. Sixty-three (72%) shocks were appropriate, and 24 (28%) were inappropriate (T-wave oversensing 7 [29%], supraventricular arrhythmia 16 [67%], after self-terminating VF 1 [4%]).
  
  
  RESULTS
  Among appropriate shocks, 20 (32%) were effective in terminating sustained arrhythmia and 43 (68%) were ineffective. Shocks delivered to triggered arrhythmias nearly always failed (1 of 40 [3%] effective), while shocks delivered to VF were usually successful (19 of 23 [83%] effective; P < .001). Four patients received 17 appropriate antitachycardia pacing therapies for ventricular tachycardia: only 2 (12%) were effective. No patient died.
  
  
  CONCLUSIONS
  The effectiveness of ICD shock therapy in CPVT depends on the mechanism of the rhythm treated. Shocks delivered to initiating triggered arrhythmias nearly always fail, whereas those for subsequent VF are usually effective. ICD programming in these patients is exceptionally challenging.
authors.affiliation: Department of Cardiology, Royal Brompton Hospital, London, United Kingdom.
authors.forename: Ferran
authors.initials: F
authors.lastname: Roses-Noguer
authors.affiliation: Department of Cardiology, Royal Brompton Hospital, London, United Kingdom.
authors.forename: Julian W E
authors.initials: JW
authors.lastname: Jarman
authors.affiliation: Department of Cardiology, Royal Brompton Hospital, London, United Kingdom.
authors.forename: Jonathan R
authors.initials: JR
authors.lastname: Clague
authors.affiliation: Department of Cardiology, Royal Brompton Hospital, London, United Kingdom. Electronic address: j.till@rbht.nhs.uk.
authors.forename: Jan
authors.initials: J
authors.lastname: Till
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D016757:Death, Sudden, Cardiac / Q000453:epidemiology / Q000517:prevention & control; D017147:Defibrillators, Implantable; D004562:Electrocardiography; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D012189:Retrospective Studies; D017180:Tachycardia, Ventricular / Q000401:mortality / Q000503:physiopathology / Q000628:therapy*; D016896:Treatment Outcome; D006113:United Kingdom / Q000453:epidemiology; D055815:Young Adult; D000098850:Polymorphic Catecholaminergic Ventricular Tachycardia
keywords: ATP; CI; CPVT; Catecholaminergic polymorphic ventricular tachycardia; ECG; ETT; ICD; Implantable cardioverter-defibrillator; LCSD; MVT; PVT; Pediatric; RGPVA; S-ICD; Sudden cardiac death; VF; VT; antitachycardia pacing; catecholaminergic polymorphic ventricular tachycardia; confidence interval; electrocardiogram; exercise tolerance test; implantable cardioverter-defibrillator; left cardiac sympathetic denervation; monomorphic ventricular tachycardia; polymorphic ventricular tachycardia; repeated grouped polymorphic ventricular activity; subcutaneous implantable cardioverter-defibrillator; ventricular fibrillation; ventricular tachycardia