How do electrical signals travel from the sinoatrial node through the heart?

In birds and mammals, the heartbeat is initiated by specialized pacemaker cells in the sinoatrial node, located in the right atrium. These cells generate an electrical impulse that spreads as a wave of depolarization through the heart's conduction system.123

The signal travels from the sinoatrial node through specialized atrial conduction tissue toward the septum between the atria. After reaching the atrioventricular node, the signal undergoes a slight delay before progressing through the bundles of His and Purkinje cells. This pathway ensures the electrical excitation is transmitted rapidly down to the ventricles, followed by a slower dispersion of the signal throughout the ventricular muscle cells. This highly coordinated process ensures the efficient, rhythmic contraction of the atria and ventricles required to pump blood throughout the body.2314