The electrical impulse is delayed in the AV node before propagating to the AV bundle (of His). During this delay the __ contract.

During this pause at the AV node, the atria contract, pushing blood into the ventricles. This coordinated timing ensures that the ventricles fill up completely before they receive the electrical signal to contract, optimizing the heart's efficiency. After the delay, the electrical impulse travels down the AV bundle, prompting the ventricles to contract and pump blood throughout the body. This sequential contraction is crucial for maintaining proper blood circulation and ensuring every heartbeat is effective.