Abstract
Long QT syndrome (LQTS) is an arrhythmic heart disease caused by congenital genetic mutations, and results in increased occurrence rates of polymorphic ventricular tachyarrhythmias and sudden cardiac death (SCD). Clinical evidence from numerous previous studies suggested that beta blockers (BBs), including atenolol, propranolol, metoprolol, and nadolol, exhibit different efficacies for reducing the risk of cardiac events (CEs), such as syncope, arrest cardiac arrest (ACA), and SCD, in patients with LQTS. In this study, we identified relevant studies in MEDLINE, PubMed, embase, and Cochrane databases and performed a meta-analysis to assess the relationship between the rate of CEs and LQTS individuals with confounding variables, including different gender, age, and QTc intervals. Moreover, a network meta-analysis was not only established to evaluate the effectiveness of different BBs, but also to provide the ranked efficacies of BBs treatment for preventing the recurrence of CEs in LQT1 and LQT2 patients. In conclusion, nadolol was recommended as a relatively effective strategy for LQT2 in order to improve the prognosis of patients during a long follow-up period.
Highlights
Congenital long QT syndrome (LQTS) is characterized by a prolonged QT interval and action potential duration (APD)
Our analysis showed that before puberty, male and female LQTS patients had a similar likelihood of experiencing cardiac events (CEs)
CE risk was higher in LQT1 patients than in LQT2 patients at the age of 10 (HR 1.52, 95% confidence intervals (CIs) 1.08–2.14; I2 0%, p 0.79; Figure 2C)
Summary
Congenital long QT syndrome (LQTS) is characterized by a prolonged QT interval and action potential duration (APD). Patients with LQTS have a propensity to develop ventricular tachycardia (VT) and have a higher rate of cardiac events (CEs) (Arking et al, 2014). The three major genotypes of LQTS, LQT1, LQT2, and LQT3, account for 80–90% of all 15 gene-mutations identified in LQTS patients (Tester and Ackerman, 2014). LQT1, as the prevailing inherited genotype of LQTS, results from gain-of-function mutations in a slow potassium (K+) outward current channel encoded by KCNQ1. LQT2 is associated with dysfunction of a rapid K+ channel encoded by the KCNH2 gene. Mutations in the SCN5A gene trigger enhanced levels of late sodium (Na+) inward current, which is the pathomechanism of LQT3 (Maguy et al, 2020)
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