When a patient is admitted with an accelerated junctional rhythm, which of the following could be a contributing factor?

• A. Hypertension
• B. Stress
• C. Digoxin toxicity
• D. Arrhythmogenic right ventricular dysplasia

Answer: (C)

An accelerated junctional rhythm occurs when the junctional tissue (the area between the atria and ventricles) becomes more electrically active, leading to increased heart rate originating from the AV junction. Among the factors that can influence this rhythm, digoxin toxicity stands out as particularly relevant.

Digoxin is a medication often used to treat heart conditions, especially heart failure and certain arrhythmias. However, it has a narrow therapeutic index, meaning that the difference between an effective dose and a toxic dose is small. When digoxin levels become too high in the bloodstream, it can lead to various electrophysiologic changes in the heart, one of which can be an accelerated junctional rhythm. This happens because digoxin increases vagal tone and can cause escape rhythms to speed up, affecting the AV junction's impulses.

Other factors, such as hypertension or stress, might contribute to arrhythmias in a broader sense, but they are not specific triggers for an accelerated junctional rhythm. Meanwhile, arrhythmogenic right ventricular dysplasia (ARVD) is a structural abnormality and primarily impacts ventricular rhythms rather than junctional rhythms. Therefore, while all these elements can influence heart rhythms, digoxin toxicity is specifically tied to the mechanisms that can lead to an accelerated