Introduction: The incidence of appropriate and inappropriate discharges, indicators of system failure, and clinical implications of implantable cardioverter defibrillator (ICD) therapy in children and young adults with heart disease is poorly defined.
Methods and results: In a retrospective study at a single medical center, a total of 90 ICD procedures were performed in 76 patients younger than age 30 years (median 16 years, range 1-30): 42% with congenital heart disease, 33% with primary electrical disease, 17% with hypertrophic cardiomyopathy, and 8% with idiopathic dilated cardiomyopathy. Indications for ICD included arrest or sustained ventricular tachycardia (n = 27), and combinations of syncope (n = 32), palpitations (n = 17), spontaneous ventricular arrhythmia (n = 40), inducible ventricular tachycardia (n = 36), or severe hypertrophic cardiomyopathy. Transvenous dual-chamber ICDs were implanted in 29 patients. Subcutaneous arrays or epicardial patches were used in 9 patients. Over a median 2-year follow-up, 28% of patients received appropriate shocks for ventricular tachycardia (median 13 months to first shock) and 25% experienced inappropriate shocks for multiple causes (median 16 months). With multivariate analysis, growth strongly correlated with lead failure (odds ratio 73, 3.5-1530, P = 0.006). Complications occurred in 29 patients, including lead failure in 16 (21%), ICD "storm" with sequential shocks in 5, and infection in 2 patients. No deaths were attributable to ICD placement or subsequent device failure.
Conclusion: ICD therapy can effectively manage malignant arrhythmias in selected pediatric and congenital heart patients. Spurious shocks or ICD storm may increase morbidity and emphasize the need for concomitant medical and ablative therapy. ICD lead failure was relatively frequent in this population.