ECG changes in patients on chronic psychotropic medication

Abstract

Objectives. To determine the ECG changes in a group of outpatients on chronic psychotropic medication, and the association, if any, with factors such as gender, age, co- morbid illness and the use of concomitant medication.

Methods. Study subjects included patients 18 years and older attending the outpatient departments of Chris Hani Baragwanath and Johannesburg hospitals. The subjects’ demographic and clinical characteristics were obtained and a resting ECG was recorded.

Results. Eighty patients were included in the study. The mean age of the subjects was 45.4 (standard deviation (SD) =18.2) years, with a minimum age of 18 and a maximum of 86 years. Fifty-four subjects (67.5%) had evidence of some ECG abnormalities. There was no significant difference between the occurrence of ECG abnormalities and the different age groups (p > 0.05), gender (p > 0.05), and different race groups (p > 0.05). Sixty-one subjects (76.3%) had no co-morbid medical illness and were on psychotropic medication only; of these patients 43 (70.5%) had abnormal ECG tracings (p > 0.05). The ECG abnormalities recorded included abnormal rate (28.8%), abnormal ST segment (20.5%), abnormal QRS complex (17.8%), abnormal T wave (15.4%), prolonged or borderline corrected QT interval (8.2%), irregular rhythm (5.5%) and prolonged PR interval (2.7%). There was a significant positive correlation between the corrected QT interval and age (r = 0.43, p < 0.05) and between corrected QT interval and female gender (r = 0.31, p < 0.05). There was no correlation between corrected QT interval and treatment of a co-morbid illness (r = 0.13, p > 0.05).

Conclusion. The use of psychotropic drugs is associated with ECG changes in ordinary doses. However, this study serves to strengthen previous evidence that, although common, most of these changes are of a benign nature.