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Home Books The Atlas of Emergency Medicine, 5e

23-52: Tricyclic Antidepressant Effect

Maite A. Huis in ‘t Veld; Amal Mattu; R. Jason Thurman

ECG Findings

  • Tachycardia

  • QRS complex widening

  • QT prolongation

  • Prominent terminal R wave in aVR or V1

  • Prominent S in lead I

Pearls

  1. Tricyclic antidepressants (TCAs) produce their effects by several mechanisms. Anticholinergic effects may induce tachycardia, and sodium channel blockage may lead to QRS widening.

  2. The QRS widening seen in a TCA overdose has a nonspecific pattern and is typically unlike any bundle branch block morphology.

  3. ECG effects are rate dependent and become more pronounced with tachycardia and acidosis.

FIGURE 23.53A

Tricyclic Antidepressant Toxicity. (ECG contributor: Saralyn R. Williams, MD.)

An E C G tracing with 12 leads demonstrates tricyclic antidepressant toxicity.
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An E C G tracing with 12 leads demonstrates tricyclic antidepressant toxicity.
FIGURE 23.53B

Prominent S wave in lead I (arrowhead) with prominent terminal R wave in aVR (arrow). The QRS complex is wide (double arrow), the QT interval is prolonged, and the patient is tachycardic.

An E C G tracing of two leads. Lead 1 consists of a notched dip and a wide, curved peak. An arrowhead points to the notch. A double-headed arrow extends across the dip. Lead a V R consists of a curved peak, a dip, and a wide, sharp peak. An arrow points to the sharp peak.
View Full Size||Download Slide (.ppt)
An E C G tracing of two leads. Lead 1 consists of a notched dip and a wide, curved peak. An arrowhead points to the notch. A double-headed arrow extends across the dip. Lead a V R consists of a curved peak, a dip, and a wide, sharp peak. An arrow points to the sharp peak.

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