Final answer:
The junctional rhythm treated with atropine is bradyarrhythmia related to AV nodal blocks. Atropine increases heart rate by blocking acetylcholine's slowing effect on the heart, and is used when symptomatic or risky bradycardia is present.
Step-by-step explanation:
The junctional rhythm that is commonly treated with atropine is bradyarrhythmia, particularly the type associated with AV nodal blocks. Atropine works by blocking the action of the vagus nerve on the heart, thus increasing the heart rate by preventing acetylcholine from slowing it down.
In scenarios where the heart rate is too slow (bradycardia), leading to significant symptoms or risks, atropine may be used to temporarily speed up the heart rate while other treatments such as the implantation of an artificial pacemaker are considered.