Which arrhythmia is commonly caused by digoxin toxicity?

• A. Atrial Tachycardia
• B. Atrial Fibrillation
• C. Junctional Tachycardia
• D. Accelerated Junctional Rhythm

Answer: (C)

Digoxin toxicity commonly drives the AV junction to become an ectopic pacemaker, so the rhythm that often appears is a junctional tachycardia. This originates in the AV node region, producing a fast rhythm with narrow QRS complexes and P waves that may be buried in or inverted with respect to the QRS. The toxicity shifts the balance from normal sinus pacing to automaticity at the AV junction due to digitoxin’s effects on calcium handling and autonomic tone, making junctional tachycardia a classic and recognizable manifestation. While other digoxin-related arrhythmias can occur, they are less characteristic as the primary presentation, whereas a junctional tachycardia is the most telling sign of digitoxin toxicity.