Pacing Non-Capture in a Child with Compound Heterozygous SCN5A Mutations

Apinya Bharmanee, James M Gala

Abstract

Mutations in the cardiac sodium channel gene SCN5A are linked to arrhythmias, cardiac conduction defects and cardiomyopathies. We report a 2 year old toddler with symptomatic sinus node dysfunction, negative family history, and increased left ventricular trabeculations. He underwent an unsuccessful attempt at transvenous pacemaker implantation, with no pacing capture at multiple ventricular and atrial sites. He required resuscitation for ventricular fibrillation, and was placed on extracorporeal membrane oxygenation (ECMO) support. Genetic analysis revealed compound heterozygous SCN5A loss-of-function and gain-offunction mutations, individually inherited from both his parents. In addition to the full spectrum of manifestations of SCN5A mutations, our patient also exhibited ventricular inexcitability.