ANALYSIS OF PHARMACOLOGICAL THERAPY IN CARDIOLOGY HOSPITAL PATIENTS WITH DRUG-INDUCED QT INTERVAL PROLONGATION

Background: The most common reason for drug-induced long QT syndrome is the intake of class III antiarrhythmic agents (according to the Vaughan-Williams classification). Their therapeutic effect is based on the ventricular repolarization deceleration and QT interval prolongation. Combined therapy with antiarrhythmic agents and other drugs increases the risk of QT interval prolongation. Objective: To assess the quantitative and qualitative structure of pharmacological therapy in patients who receive antiarrhythmic therapy during their inpatient treatment in a cardiology hospital. Material and methods: A retrospective analysis of the medical records of 120 patients, predominantly of those with ischemic heart disease, arterial hypertension and cardiac arrhythmias was carried out. All patients were divided into 2 groups based on the degree of QT interval prolongation in response to antiarrhythmic therapy. All drug therapies were recorded (name, dose, frequency and duration of drug intake, indicated in the prescription sheet). Only the drugs included in the international Crediblemeds Database were considered to have influence on the duration of the QT interval. Results: The patients of both groups had no statistically significant differences in terms of the total number of drugs taken (7.3±2.4 in the first group versus 6.92±1.6 in the second group, p=0.12). The percentage ratio of drugs that affect the duration of the QT interval to the total amount of the drugs used was 26±15% in the first group and 20.5±8% in the second group, p=0.71. When assessing the duration of the corrected QT interval depending on the structure of the combinations of drugs used, the highest incidence of torsades de pointes and the highest corrected QT interval values (503.45±23.9 ms) were recorded in the subgroup of patients taking 3 such drugs at the same time. Conclusions: A positive correlation was established between the number of drugs that prolong the QT interval and the value of the corrected QT interval. No statistically significant differences were found in the quantitative and qualitative structure of pharmacological therapy in patients with and without prolongation of the QT interval.