Electrocardiogram Abnormalities Following Diphenhydramine Ingestion: A Case Report.

Unlabelled: In the United States, tricyclic antidepressants (TCA) are commonly prescribed to treat psychiatric illnesses and neuropathic pain. This class of antidepressants has been found to cause pathognomonic electrocardiogram (ECG) changes in cases of overdose.1 Specifically, TCA's cause a dominant terminal R wave in aVR and widening of the QRS complex due to their sodium channel blocking effect.