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.

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