Long-Term Follow-Up of Idiopathic Ventricular Fibrillation in a Pediatric Population: Clinical Characteristics, Management, and Complications

Background-The natural history and long-term outcome in pediatric patients with idiopathic ventricular fibrillation (IVF) are poorly characterized. We sought to define the clinical characteristics and long-term outcomes of a pediatric cohort with an initial diagnosis of IVF.Methods and Results-Patients were included from an International Registry of IVF (consisting of 496 patients). Inclusion criteria were: (1) VF with no identifiable cause following comprehensive analysis for ischemic, electrical or structural heart disease and (2) age <= 16 years. These included 54 pediatric IVF cases (age 12.7 +/- 3.7 years, 59% male) among whom 28 (52%) had a previous history of syncope (median 2 syncopal episodes [interquartile range 1]). Thirty-six (67%) had VF in situations associated with high adrenergic tone. During a median 109 +/- 12 months of follow-up, 31 patients (57%) had recurrence of ventricular arrhythmias, mainly VF. Two patients developed phenotypic expression of an inherited arrhythmia syndrome during follow-up (hypertrophic cardiomyopathy and long QT syndrome, respectively). A total of 15 patients had positive genetic testing for inherited arrhythmia syndromes. Ten patients (18%) experienced device-related complications. Three patients (6%) died, 2 due to VF storm.Conclusions-In pediatric patients with IVF, a minority develop a definite clinical phenotype during long-term follow-up. Recurrent VF is common in this patient group.