Which node electrically connects the atria and ventricles?

The atrioventricular node serves as the key electrical connection between the atria and the ventricles. It is responsible for receiving electrical impulses from the sinoatrial node, which is the heart's natural pacemaker located in the right atrium, and then delaying those impulses slightly before transmitting them to the ventricles. This delay allows the atria to fully contract and pump blood into the ventricles before they contract.

The Atrioventricular (AV) node is strategically located at the junction of the atria and ventricles, ensuring that the timing of the electrical signals is coordinated, which is crucial for the efficient functioning of the heart. If the AV node did not perform this role, it would lead to a lack of sync in the contraction of the atria and ventricles, impairing the heart's ability to pump blood effectively.

In contrast, while the sinoatrial node initiates the heart rhythm, it does not connect the two chambers directly. The Purkinje fibers and the AV bundle relay electrical impulses but do so after the AV node has performed its critical function.