Case report: an underdiagnosed multifocal ectopic Purkinje-related premature contractions caused by SCN5A mutation.

Multifocal Ectopic Purkinje-related Premature Contractions (MEPPC) syndrome is a recently recognized rare channelopathy caused by gain-of-function mutations in the SCN5A gene, leading to a high burden of premature ventricular contractions (PVCs) originating from the Purkinje system and often manifesting as a dilated cardiomyopathy-like phenotype. This case report presents a young woman without structural heart abnormalities or a known family history of similar conditions who was initially diagnosed with idiopathic fascicular ventricular arrhythmia (VAs) and underwent two unsuccessful radiofrequency ablations. The arrhythmias were successfully suppressed by flecainide, a sodium-channel blocker, after genetic testing confirmed the diagnosis of MEPPC caused by the R222Q SCN5A mutation. The case underscores the significance of genetic testing for SCN5A mutations in patients with multifocal Purkinje-related VAs, even when they lack structural heart abnormalities or a family history, to facilitate early identification and improve outcomes. Further research is required to fully understand the clinical spectrum of MEPPC and its impact on cardiac function, as well as to develop tailored treatment strategies for affected individuals.