Molecular genetic markers of QT interval duration and sudden cardiac death: literature review

The study of sudden cardiac death (SCD) and its etiopathogenesis in cardiology practice remains one of the most pressing public health problems. In Western countries, SCD accounts for 20% of the total mortality and 50% of mortality associated with cardiovascular diseases. Considering the electrical instability in the myocardium as one of the main reasons for the development of life-threatening arrhythmias (ventricular tachycardia / ventricular fibrillation) and SCD, one should be aware of such provoking factors as ischemic heart disease, myocarditis, valvular heart disease, pharmacological influences, cardiomyopathy, and channelopathy. An increase or decrease in the duration of the QT interval, which reflects the work of ion channels, as well as ventricular depolarization and repolarization, increases the risk of SCD. The aim of this review was to study and analyze the available literature data on the relationship of molecular genetic markers with the duration of the QT interval. Currently, there is a number of genetic studies that allow to identify a large number of mutations and polymorphisms of known genes that affect the variability of the QT interval, showing their significance in risk stratification of sudden arrhythmic death and choosing the right tactics for managing, preventing, and treating patients, thus reducing the risk of SCD. The predictive value of genetic testing is the highest for long QT syndrome (LQTS), for which a gene-specific risk profile has been established, and lower for other channelopathies. A large amount of genetic data may be a promising approach to quantifying the risk of SCD, especially at a young age, which will be facilitated by further study of this problem.