Gender electrocardiographic features in patients with drug-induced long QT syndrome caused by antiarrhythmic therapy

Abstract

Female gender is traditionally considered to be a risk factor for the QT interval prolongation and polymorphic ventricular tachycardia «torsades de pointes». However, despite a large number of studies on electrocardiographic features in patients with congenital long QT interval syndrome, there is relatively little information on gender ECG differences in the drug-induced QT interval prolongation.The aim of this study is to evaluate the gender characteristics of electrocardiographic parameters characterizing myocardial depolarization and repolarization in patients with drug-induced QT interval prolongation induced by class III antiarrhythmic drugs.67 patients with drug-induced QT interval prolongation induced class III antiarrhythmic drugs (amiodarone or sotalol) were examined, of which 38 (56.8 %) women and 29 (43.2 %) men, mean age – 57.1 ± 9.5 years. All patients underwent clinical laboratory and non-invasive electrophysiological studies, which included 12-lead ECG recording and 24-hour Holter monitoring. The patients of both genders were comparable in age and clinical characteristics, with the exception of a higher prevalence of AF in men (82.7 % vs 52.6 %, p = 0.03). The total duration of taking class III antiarrhythmic drugs in male patients was 3.79 ± 1.49 days, which significantly differed from female patients (3.11 ± 1.15 days, p = 0.044). When analyzing the initial standard ECG of patients recorded before starting antiarrhythmic drugs, there were no statistically significant differences between the groups, with the exception of large values of the corrected cardioelectrophysiological balance index (QTc/QRS) in female patients ( p = 0.037). While taking class III antiarrhythmic drugs, women had a higher duration of QTc ( p = 0.03) and JTc ( p = 0.023) intervals, as well as a dispersion of QT ( p = 0.012) and JT ( p = 0.006) intervals. According to Holter monitoring data, female patients were more likely to have an increased risk of developing non-sustained polymorphic VT ( p = 0.105).These results suggest a complex interplay between gender and repolarization that needs further investigation. Considering the gender characteristics of the process of myocardial repolarization, it should be taken into account not only when prescribing class III antiarrhythmic drugs to women, but also during preclinical and clinical development of drugs that have the QT interval prolonging effect.