What critical dysrhythmias are associated with tricyclic antidepressant toxicity?

Tricyclic antidepressant (TCA) toxicity is particularly known for causing certain critical dysrhythmias primarily related to its effects on cardiac conduction. One characteristic manifestation of TCA overdose is sinus tachycardia. This occurs due to the anticholinergic effects of the drugs involved, leading to increased heart rate.

In addition to sinus tachycardia, TCA toxicity is also associated with the prolongation of PR intervals. This prolongation is a result of the drug’s effects on the conduction system of the heart. TCAs can inhibit sodium channels, leading to slower conduction through the atrioventricular (AV) node and contributing to the increased interval observed on an electrocardiogram (ECG).

Together, these two effects—sinus tachycardia and prolongation of PR intervals—are classic indicators of TCA toxicity, making this combination critical for clinicians to recognize when assessing a patient with suspected overdose. By understanding these dysrhythmias, emergency medicine practitioners can initiate appropriate interventions to manage the patient's condition effectively.