Chlorpromazine-induced electrocardiogram abnormalities

The aim of our clinical investigation was to evaluate the electrocardiographic abnormalities in patients receiving only chlorpromazine, and to assess the role of sex, age and length of illness in these abnormalities. 96 schizophrenic patients (48 male and 48 female patients) satisfying study criteria were selected for inclusion and changed from their old medication to a fixed dose of 125 mg chlorpromazine daily. This uniformization period lasted two weeks, during which the electrocardiograms were taken after an overnight fast. Five patients were excluded because their electrocardiographic changes revealed the possibility of an organic heart disease. The electrocardiograms were found to be normal for 65.9% of the patients and abnormal for 34.1%. 11% of patients were classified as demonstrating Grade I repolarization abnormalities, 14.3% of patients as Grade II, and 8.8% as Grade III. Chi square (X2) tests revealed no significant differences between sexes, age groups or lenghts of illness as regards ECG normality and grade of abnormality.