A comparative study of the electrocardiographic effects of tranylcypromine and amitriptyline when prescribed singly and in combination.

The authors treated 53 in-patients aged between 18 and 65 years who were suffering from major depression with either tranylcypromine, amitriptyline or a combination of tranylcypromine and amitriptyline. Electrocardiograms taken before and after treatment were compared. In clinically effective doses amitriptyline gave rise to a significant increase in heart rate when prescribed alone and in combination with tranylcypromine. Single tranylcypromine treatment had little effect on heart rate and gave rise to no change in cardiac conduction as measured by the electrocardiogram. Amitriptyline when prescribed in combination with tranylcypromine was associated with significant lengthening of the PR interval. None of the patients developed pathological changes in their electrocardiograms under the carefully monitored treatment conditions of the study.