Serial Monitoring of Lead aVR in Patients with Prolonged Unconsciousness Following Tricyclic Antidepressant Overdose

Severe cardiac and neurologic toxicities of tricyclic antidepressant (TCA) overdose have been reported since the introduction of TCAs in 1950s. Despite the decreased numbers of TCA overdoses, the mortality and morbidity rates of TCA overdose have remained constantly high. Clinical manifestations of TCA overdose are characterized by unconsciousness and specific electrocardiography (ECG) abnormalities such as prolongation of the PR and QTc intervals, widening of the QRS duration, and an increased R wave and R/S ratio in lead aVR. We report a case with unusually prolonged unconsciousness without initial stem reflexes for 7 days and multiple ECG abnormalities following TCA overdose. It is suggested that the serial monitoring of R wave and R/S ratio in lead aVR might be informative in predicting recovery from toxicity following TCA overdose.