Congenital Long Qt Syndrome as a Clinical Marker of Arrhythmias and Sudden Death in Children (Review)

Introduction. Congenital long QT syndrome (LQTS) is a genetically determined ion channel disease characterized by QT prolongation and the occurrence of polymorphic ventricular tachycardia, known as torsades de pointes (TdP), which can lead to syncope and sudden cardiac death in children. Methods. The aim of this study was to analyze the available scientific, professional, and specialized literature on the diagnosis and treatment of congenital long QT syndrome. An information search for sources of scientific and medical data on the Internet was performed, in particular on scientific aggregator sites — "PubMed", "ResearchGate", "Google Scholar", "Medscape" and "MedlinePlus". The search depth was 10 years, the sources of information were categorized after their preliminary assessment, giving preference to publications with a potentially higher level of evidence. Results and their discussion. Two clinical phenotypes have been described for LQTS: a common autosomal dominant form, known as Romano-Ward syndrome, characterized by a cardiac phenotype of QT prolongation, and a rare autosomal recessive form, Jervell-Lange-Nielsen syndrome, which is associated with sensorineural deafness. LQT syndrome remains one of the most common inherited arrhythmias and is a leading cause of sudden cardiac death. The prevalence of LQTS is approximately 1 in 2000 live births. Rapid advances in genetic technologies over the past two decades have significantly enhanced our understanding of the molecular genetic mechanisms underlying LQT. Studies have shown that children with a corrected QT interval (QTc — a calculated measure that reflects the heart rate-adjusted QT interval) of more than 500 milliseconds are at increased risk of developing life-threatening arrhythmias and RCC. Early diagnosis and treatment of QT prolongation is crucial, as timely intervention can significantly reduce mortality in children. Patients with LQTS should avoid medications that prolong the QT interval, maintain proper electrolyte balance, and control psychological stress to prevent arrhythmic events. Conclusions. Long QT syndrome is a potentially life-threatening condition characterized by a prolonged QT interval on the electrocardiogram, which can lead to dangerous arrhythmias and sudden cardiac arrest. The danger of LQTS for the patient is the risk of sudden death. The diagnosis of LQTS is based on electrocardiogram analysis, genetic testing, and a thorough family history. Treatment strategies primarily include beta-blockers, calcium and sodium channel blockers, and lifestyle modifications, all aimed at reducing the risk of arrhythmia development.