What condition involves the AV node delaying impulses from the atria to the ventricles?

The condition that involves the AV node delaying impulses from the atria to the ventricles is first-degree heart block. In this situation, there is a consistent but prolonged delay in the conduction through the AV node. This can be identified on an electrocardiogram (ECG) by a prolonged PR interval, which is the time it takes for impulses to travel from the atria to the ventricles.

It’s important to note that in first-degree heart block, all atrial impulses do reach the ventricles, but the delay is evident. In contrast, second-degree heart block involves intermittent failure of conduction, meaning some impulses do not reach the ventricles, and third-degree heart block indicates a complete block where the atria and ventricles are functioning independently of one another. Atrial fibrillation, while it involves irregular atrial activity, is not characterized by a delay at the AV node but rather an erratic transmission of impulses. This understanding clarifies why first-degree heart block represents the condition with the described characteristics accurately.