SERUM TESTOSTERONE LEVEL AS A PREDICTOR OF DRUG-INDUCED QT INTERVAL PROLONGATION AND POLYMORPHOUS VENTRICULAR TACHYCARDIA IN MALE PATIENTS TAKING CLASS III ANTIARRHYTHMIC DRUGS

Background. A decrease in serum testosterone level in men is associated with QT interval prolongation on the standard ECG due to changes in the functioning of potassium and calcium ion channels. The scientific literature provides relatively little information on the combined effects of testosterone deficiency and intake of class III antiarrhythmic drugs on the process of myocardial repolarization and development of polymorphic ventricular arrhythmias associated with drug-induced QT prolongation (LQTS). The aim of this study was to establish the prognostic value of serum testosterone levels for the development of drug- induced QT interval prolongation and polymorphic ventricular tachycardia (PVT). Material and methods. To achieve this goal, 59 male patients were examined, mainly those with coronary heart disease, arterial hypertension and cardiac arrhythmias, 29 (49.2%) of which had drug-induced LQTS and 30 (50.8%) were with normal values of the QT interval while taking antiarrhythmic therapy. All patients underwent clinical, laboratory and instrumental studies, including the determination of serum testosterone levels. Results. The patients with drug-induced LQTS had lower testosterone levels compared to patients without LQTS (p<0.001), especially in the middle and older age groups according to the WHO age classification (p=0.009). An inverse correlation relationship (p<0.01) was found between the serum testosterone level and a number of electrocardiographic parameters, including the duration of the corrected QT interval (R=-0.56), the interval T peak - T end (R=-0.58) and corrected cardioelectrophysiological balance index (R=-0.43). Testosterone levels were lower in patients with drug-induced LQTS and PVT than in patients without PVT (p=0.031). The testosterone value ≤13.43 nmol/ml demonstrated high sensitivity (100%) and specificity (78.43%), as well as a fairly high area under the ROC curve (0.917) and can be used to predict non-sustained PVT in male patients taking amiodarone and sotalol (OR=5.50 [95% CI 3.14; 9.63]). Conclusions. Our data indicate an important pathophysiological role of testosterone in the genesis of drug-induced LQTS and PVT development in male patients. Given the small size of the study sample, the applicability of this indicator needs to be tested on a larger group of patients.