Cavotricuspid isthmus ablation and subcutaneous monitoring device implantation in a 2-year-old baby with 2 SCN5A mutations, sinus node dysfunction, atrial flutter recurrences, and drug induced long-QT syndrome: a tricky case of pediatric overlap syndrome?

We describe the case of 2-year-old baby with compound heterozygosity for paternal and maternal alleles mutation of α-subunit of the cardiac sodium channel (SCN5A), sinus node dysfunction, atrial flutter recurrences, and drug induced long-QT syndrome. In this setting, we chose at first to perform linear ablation of cavotricuspid isthmus resulting in a bidirectional isthmus block. As a second step, we decided to implant a miniaturized loop recorder that, with a minimally invasive procedure, permits us to follow the development of the disease in order to define the future strategy. After 8 months follow-up, automatic daily loop-recorder transmissions disclose the complete absence of any arrhythmia along with asymptomatic ventricular pauses due to sinus node dysfunction. Echocardiography shows normal findings, in particular no left ventricular dysfunction.