BACKGROUND: Catecholaminergic polymorphic ventricular tachycardia (CPVT) may cause sudden cardiac death (SCD) despite medical therapy. Therefore, implantable cardioverter-defibrillators (ICDs) are commonly advised. However, there is limited data on the outcomes of ICD use in children. OBJECTIVE: The purpose of this study was to compare the risk of arrhythmic events in pediatric patients with CPVT with and without an ICD. METHODS: We compared the risk of SCD in patients with RYR2 (ryanodine receptor 2) variants and phenotype-positive symptomatic CPVT patients with and without an ICD who were younger than 19 years and had no history of sudden cardiac arrest at phenotype diagnosis. The primary outcome was SCD; secondary outcomes were composite end points of SCD, sudden cardiac arrest, or appropriate ICD shocks with or without arrhythmic syncope. RESULTS: The study included 235 patients, 73 with an ICD (31.1%) and 162 without an ICD (68.9%). Over a median follow-up of 8.0 years (interquartile range 4.3-13.4 years), SCD occurred in 7 patients (3.0%), of whom 4 (57.1%) were noncompliant with medications and none had an ICD. Patients with ICD had a higher risk of both secondary composite outcomes (without syncope: hazard ratio 5.85; 95% confidence interval 3.40-10.09; P < .0001; with syncope: hazard ratio 2.55; 95% confidence interval 1.50-4.34; P = .0005). Thirty-one patients with ICD (42.5%) experienced appropriate shocks, 18 (24.7%) inappropriate shocks, and 21 (28.8%) device-related complications. CONCLUSION: SCD events occurred only in patients without an ICD and mostly in those not on optimal medical therapy. Patients with an ICD had a high risk of appropriate and inappropriate shocks, which may be reduced with appropriate device programming. Severe ICD complications were common, and risks vs benefits of ICDs need to be considered.

Agnes Ginges Centre for Molecular Cardiology at Centenary Institute The University of Sydney Sydney Australia; Faculty of Medicine and Health The University of Sydney Sydney Australia

Amsterdam UMC University of Amsterdam Heart Centre Department of Clinical and Experimental Cardiology Amsterdam Cardiovascular Sciences Heart Failure and Arrhythmias Amsterdam the Netherlands

Amsterdam UMC University of Amsterdam Heart Centre Department of Clinical and Experimental Cardiology Amsterdam Cardiovascular Sciences Heart Failure and Arrhythmias Amsterdam the Netherlands; Department of Pediatric Cardiology Amsterdam UMC University of Amsterdam Emma Children's Hospital Amsterdam The Netherlands

BC Children's Hospital Division of Cardiology Department of Pediatrics The University of British Columbia Vancouver British Columbia Canada

BC Children's Hospital Division of Cardiology Department of Pediatrics The University of British Columbia Vancouver British Columbia Canada; Center for Cardiovascular Innovation Division of Cardiology The University of British Columbia Vancouver Canada

Cardiac Inherited Disease Group New Zealand Green Lane Paediatric and Congenital Cardiac Services Starship Children's Hospital Auckland New Zealand; Department of Paediatrics Child and Youth Health The University of Auckland Auckland New Zealand

Cardiology Faculty of Medicine and Dentistry Pediatrics Dept Stollery Children's Hospital Edmonton Canada

Center for Cardiovascular Innovation Division of Cardiology The University of British Columbia Vancouver Canada

Centro de Investigación Biomédica en Red de Enfermedades Cardiovasculares University of Girona Girona Spain; Medical Science Department School of Medicine University of Girona Girona Spain; Cardiology Service Hospital Josep Trueta Girona Spain

Children's Hospital Los Angeles Los Angeles California

Department of Cardiology Rigshospitalet Department of Forensic Medicine Faculty of Medical Sciences University of Copenhagen Copenhagen Denmark

Department of Cardiology Royal Brompton Hospital London UK

Department of Cardiology Tel Aviv Sourasky Medical Center and Sackler School of Medicine Tel Aviv University Tel Aviv Israel

Department of Cardiovascular Diseases University Hospitals Leuven Belgium; Department of Cardiovascular Sciences University of Leuven Leuven Belgium

Department of Cardiovascular Medicine National Cerebral and Cardiovascular Centre Suita Japan

Department of Cardiovascular Medicine Shiga University of Medical Science Otsu Japan

Department of Cardiovascular Medicine Shiga University of Medical Science Otsu Japan; Department of Bioscience and Genetics National Cerebral and Cardiovascular Centre National Cerebral and Cardiovascular Centre Suita Japan

Department of Medicine University Medical Center Mannheim Mannheim Germany; German Center for Cardiovascular Research Partner Site Heidelberg Mannheim Germany

Department of Pediatric Cardiology Amsterdam UMC University of Amsterdam Emma Children's Hospital Amsterdam The Netherlands; Department of Pediatric Cardiology Willem Alexander Children's Hospital Leiden University Medical Centre Leiden The Netherlands

Department of Pediatric Cardiology Children's Heart Centre 2nd Faculty of Medicine Charles University Prague Motol University Hospital Prague Czech Republic

Department of Pediatric Cardiology Erasmus MC Sophia Rotterdam The Netherlands

Department of Pediatrics Monroe Carell Jr Children's Hospital at Vanderbilt Vanderbilt University Medical Centre Nashville Tennessee

Departments of Cardiovascular Medicine Pediatric and Adolescent Medicine and Molecular Pharmacology and Experimental Therapeutics; Division of Heart Rhythm Services and Pediatric Cardiology Windland Smith Rice Sudden Death Genomics Laboratory Mayo Clinic Rochester Minnesota

Division of Cardiology Department of Pediatrics Irvine and Children's Hospital of Orange County University of California Orange California

Heart and Lung Centre Helsinki University Hospital and Helsinki University Helsinki Finland

Hong Kong Children's Hospital Hong Kong SAR China

Istituto Auxologico Italiano IRCCS Center for Cardiac Arrhythmias of Genetic Origin Milan Italy

Nationwide Children's Hospital Columbus Ohio

Nemours Children's Clinic Orlando Florida

Pediatric Arrhythmias Inherited Cardiac Diseases and Sudden Death Unit Hospital Sant Joan de Déu Spain; Medical Science Department School of Medicine Universitat de Girona Girona Spain

Pediatric Cardiology and Cardiac Arrhythmias Unit Department of Pediatric Cardiology and Cardiac Surgery Bambino Gesù Children's Hospital IRCCS Palidoro Rome Italy

ProCardio Center for Innovation Department of Cardiology Oslo University Hospital Rikshospitalet Oslo Norway; and Department of Cardiology Karolinska University Hospital and Department of Medicine Huddinge Karolinska Institute Stockholm Sweden

Rady Children's Hospital San Diego California

Section of Cardiac Electrophysiology Division of Cardiology Department of Medicine Western University London Ontario Canada; Population Health Research Institute Hamilton Health Sciences and McMaster University Hamilton Ontario Canada

Service de Cardiologie et CNMR Maladies Cardiaques Héréditaires Rares Hôpital Bichat APHP Université de Paris Cité Paris France

Sibley Heart Center Children's Healthcare of Atlanta Atlanta Georgia

Université de Nantes CHU Nantes CNRS INSERM l'institut du thorax Nantes France

University of Gottingen Gottingen Germany

University of Iowa Stead Family Children's Hospital Iowa City Iowa

University of Michigan Ann Arbor Michigan

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