Last update:
04-Jun-2009

OBJECTIVE Antipsychotic drugs (AD) are prescribed frequently and they often cause serious cardiovascular side effects, especially QTc prolongation. QTc prolongation and dispersion can predict drug induced arrhythmias and are associated with the risk of sudden cardiac death. The prevalence of QTc prolongation is poorly studied in Greek inpatients in private –for– profit psychiatric clinics.

METHOD Psychiatric inpatients, 47 females and 46 males, were included in a cross-sectional study at the “Asklipeiion” clinic, Thessaloniki. The mean age of participants was 57.8 (±15.2) years and 50 of the patients were admitted for psychotic syndrome. The patients were studied in 3 age groups: 20– 39, 40–59 and >=60 years. Standard 12-lead electrocardiography (ECG) was performed for each patient. The QT interval was measured from the ECG and corrected for heart rate using the Bazett and Fridericia formula. The number and category of drugs taken by each patient was recorded.

RESULTS The mean QTc interval was 398.16 (±31.99) msec. The prevalence of QTc prolongation was estimated at 3.23% (1.11–9.07%, CI 95%). Patients with prolonged QTc had a median age of 54.7 (range 30.0–70.0) years. No statistically significant differences in QTc duration were found between men and women, among different age groups, different disease groups or among groups of patients who took different numbers of drugs.

CONCLUSIONS The prevalence of QTc prolongation in Greek psychiatric inpatients was lower than that found in previous studies. Despite the lack of statistically significant differences in QTc mean duration among the groups of inpatients, QTc measurement and prolongation remain useful clinical tools.

Key words: Antidepressants, Antipsychotic drugs, ECG, Sudden death, Torsades de pointes.