Which is NOT a manifestation of digoxin toxicity?

The correct choice indicates that rapid atrioventricular (AV) conduction is not a manifestation of digoxin toxicity. In fact, digoxin toxicity characteristically leads to various cardiac rhythm disturbances, but it often causes a decrease in the conduction rate rather than an increase. This is because digoxin increases vagal tone, which can lead to bradycardia and various types of heart block rather than a rapid response in AV conduction.

Manifestations of digoxin toxicity commonly include symptoms such as nausea and vomiting, which are gastrointestinal effects due to the drug's action on the central nervous system. Changes in vision, often referred to as "xanthopsia," involve seeing yellow or green halos, which are also well-documented effects of digoxin toxicity. Bradycardia occurs because digoxin can depress the heart rate, enhancing vagal effects on the heart.

In summary, because digoxin toxicity is more associated with reduced conduction speeds and bradyarrhythmias rather than rapid conduction, the choice that highlights rapid AV conduction as a manifestation is indeed the accurate one in this context.