Abstract 16851: Tricyclic Antidepressant Induced Wide Complex Tachycardia With Brugada Pattern

Abstract

Case Description: A 52-year-old male with bipolar disorder and depression was brought to the ED after he was found confused following an episode of syncope. He reported taking 5 pills of his new dose of Nortriptyline 75mg instead of 5 pills of his previous dose of Nortriptyline 25mg. ECG from the field showed a wide complex tachycardia (WCT) with a rightward axis and a Brugada pattern in V1 and V2 at a rate of 120-130s. Upon arrival in the ED, he continued to have WCT, and was treated with Amiodarone, Magnesium Sulfate, and Sodium Bicarbonate. Following treatment, his heart rate improved and the QRS duration shortened with a gradual loss of Brugada pattern (Figure 1). Six hours from initial presentation, his QRS completely normalized. Transthoracic echocardiogram (TTE) showed normal LV function. His presentation was consistent with tricyclic antidepressant (TCA) overdose. Discussion: The cardiotoxic effects of TCAs are mediated through their behavior as class IA antiarrhythmic drugs. This results in lengthening of both depolarization and repolarization of the cardiac action potential resulting in a widened QRS complex and QT prolongation. Sodium channel blockade can precipitate a Brugada phenotype which resolves after Sodium Bicarbonate administration. Similar to class IA agents, TCAs also exhibit use dependence and in our patient, the Brugada pattern began to resolve soon after presentation, possibly due to slowing of the tachycardia. Recognition of TCA toxicity is important to allow for timely administration of bicarbonate which facilitates prompt reversal.