What clinical feature is typical in tricyclic antidepressant overdose?

In the context of a tricyclic antidepressant (TCA) overdose, a widened QRS complex on an electrocardiogram (ECG) is a hallmark clinical feature. This widening occurs due to the blockade of sodium channels, which is a characteristic action of TCAs. This effect can lead to delayed ventricular depolarization and increases the risk of life-threatening arrhythmias, making early identification vital for appropriate management.

The widening of the QRS interval more than 100 milliseconds is particularly concerning, as it may signal significant toxicity that requires urgent intervention, such as sodium bicarbonate administration to help narrow the QRS and stabilize the cardiac membrane.

Additionally, other clinical features commonly seen in TCA overdose may include anticholinergic effects (such as dry mouth and dilated pupils), central nervous system depression, and cardiovascular manifestations (like hypotension and arrhythmias). However, among these, the widened QRS is a key indicator that physicians specifically look for during the assessment of a potential TCA overdose.