Síndrome do QT longo: mutação trigénica, um caso raro

Congenital long QT syndrome (LQTS) is a rare hereditary disease, with an incidence of 1 in 2000, characterized by prolonged ventricular repolarization and malignant ventricular tachyarrhythmias. We report the case of a 30‐year‐old woman, previously diagnosed with neurocardiogenic syncope, in whom LQTS was identified. The patient received an implantable cardioverter‐defibrillator due to polymorphic ventricular tachycardia under beta‐blocker therapy. Molecular genetic testing identified three mutations in heterozygosity in the KCNH2, KCNQ1 and SCN5A genes, which is a rare finding and is associated with worse prognosis.