The AV node functions as a critical delay in the conduction system. Without this delay, the atria and ventricles would contract at the same time, and blood would n't flow effectively from the atria to the ventricles. The delay in the AV node forms much of the PR segment on the ECG, and part of atrial repolarization can be represented by PR segment.
where is the av nodal delay represented in the ecg
PR segment PR segment