Your Heart’s Electrical System

The heart has a special system that creates and sends electrical signals. First, signals tell the atria (singular: atrium) to squeeze. This moves blood to the ventricles. Next, signals tell the ventricles to squeeze. This moves blood to the lungs and body.

Electrical Signals

Groups of special cells in the right atrium, called nodes, send the heart’s electrical signals. The signals travel along pathways. In the ventricles, these pathways are called bundle branches.

The SA Node

This sets the pace of the heartbeat. It starts each beat by releasing a signal telling the atria to squeeze.

The AV Node

This receives the signal from the atria. It is the “gateway” between the atria and the ventricles. The AV node channels the signal into the ventricles.

The Bundle Branches

These carry the signal through the ventricle walls. As the signal moves through the ventricles, the ventricles squeeze.