Subcutaneous ICD in Pediatrics and Congenital Heart Disease

Quick Takes

  • An implantable cardioverter-defibrillator (S-ICD) was successfully implanted in a wide range of patient ages and sizes, including those with complex congenital heart disease.
  • The S-ICD exhibited acceptable implant characteristics with effective acute conversion and appropriate therapy delivery.
  • In the future, the efficacy of lower defibrillation outputs, if demonstrated, may allow the development of smaller generator sizes and use of the S-ICD for younger and/or smaller patients.

Study Questions:

What is the implant experience and midterm results of subcutaneous implantable cardioverter-defibrillators (S-ICDs) in pediatric patients and those with congenital heart disease?

Methods:

The investigators conducted an international, multicenter, retrospective, standard-of-care study through the Pediatric & Congenital Electrophysiology Society. Complications at 30 and 360 days, inappropriate shocks, and delivery of appropriate therapy were assessed. A Kaplan-Meier cumulative incidence curve for the entire cohort was constructed to assess the inappropriate shock rate.

Results:

The study included 115 patients with a median follow-up of 32 (19-52) months. Median age was 16.7 years (14.8-19.3 years), 29% were female, and 55% had a primary prevention indication. Underlying disease substrate was cardiomyopathy (40%), structural heart disease (32%), idiopathic ventricular fibrillation (16%), and channelopathy (13%). The complication rate was 7.8% at 30 days and 14.7% at 360 days. Overall, inappropriate shocks occurred in 15.6% of patients, with no single clinical characteristic reaching statistical significance. At implant, 97.9% of patients had successful first shock conversion, with 96% requiring ≤65 J. Appropriate therapy was delivered to 11.2% of patients, with an annual incidence of 3.9% and an acute first shock conversion success rate of 92.5%.

Conclusions:

The authors concluded that in a heterogeneous population of pediatric patients and those with congenital heart disease, the S-ICD had comparable rates of complications, inappropriate shocks, and conversion efficacy compared with transvenous systems.

Perspective:

This study reports that an S-ICD was successfully implanted in a wide range of patient ages and sizes, including those with complex congenital heart disease. The S-ICD exhibited acceptable implant characteristics with effective acute conversion and appropriate therapy delivery. Furthermore, inappropriate shock rates were comparable to other published literature for transvenous ICDs and S-ICDs in similar patient populations. In the future, the efficacy of lower defibrillation outputs, if proven, may allow the development of smaller generator sizes and use of the S-ICD for younger and/or smaller patients.

Clinical Topics: Arrhythmias and Clinical EP, Congenital Heart Disease and Pediatric Cardiology, Heart Failure and Cardiomyopathies, Prevention, Implantable Devices, Genetic Arrhythmic Conditions, SCD/Ventricular Arrhythmias, Atrial Fibrillation/Supraventricular Arrhythmias, Congenital Heart Disease, CHD and Pediatrics and Arrhythmias, Acute Heart Failure

Keywords: Arrhythmias, Cardiac, Cardiomyopathies, Channelopathies, Defibrillators, Implantable, Electrophysiology, Heart Defects, Congenital, Heart Failure, Pediatrics, Primary Prevention, Shock, Ventricular Fibrillation


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