Atypical Antipsychotics and Prolongation of QTc Interval

Overview

The aim of our study
was to monitor the occurrence of QT interval prolongation in a non selected population of psychiatric patients treated with atypical antipsychotics in monotherapy and combined therapy. In consecutive patients hospitalized at psychotic wards at the Department of Psychiatry, Faculty of Medicine Masaryk University and Faculty Hospital Brno treated with these drugs a 12-lead ECG was recorded (50 mm/s, 20 mm/mV), QT intervals were measured manually, corrected according to Bazett. QTc intervals of 470 ms (females) and 450 ms (males) were considered borderline, longer QTc intervals were considered pathologic. ECGs were recorded in 351 patients, 180 males, 171 females. These were hospitalised with thediagnosis of schizophrenia (61.5%), bipolar disorder (21.5%) and other (17%). Abnormal QTc values were observed in 7 patients, 6 females and 1 male, 4 were borderline and 3 pathologic. Females were treated by monotherapy, males by combined therapy. Values associated with high risk of arrhythmias (over 500 ms) were not observed. This might be related to the general trend to use lower doses and increasing awareness about the drug-induced long QT syndrome.

Key words:
schizophrenia, atypical antipsychotics, side effects, QTc, ECG.