In a normal, healthy heart, the electrical conduction pathway begins with the sinoatrial node receiving an electrical signal, according to the National Heart, Lung, and Blood Institute. Next, the signal moves through the heart and reaches the atrioventricular node. Finally, the signal reaches the bundle of His-Purkinje fibers.
Each heartbeat has two basic parts that allow the heart to pump blood into and out of its chambers, states the National Heart, Lung, and Blood Institute. During diastole, the atria and ventricles relax and fill with blood, and during systole, the atria and ventricles contract and shoot blood through the systemic and pulmonary circulatory pathways. To accomplish both diastole and systole, the heart has an electrical conduction pathway that provides it with the electricity it needs to beat continuously.
The electrical signal is first generated in the sinoatrial node in the right atrium. Then, the signal travels through the vena cavae as blood fills the right atrium of the heart. Next, the electrical signal spreads through the heart's right and left atria. As the electrical signal causes the atria to contract, it reaches the atrioventricular node. The signal rejuvenates itself at the atrioventricular node and moves into the bundle of His. From the bundle of His, the signal divides into bundle branches that cover the left and right side of the heart. These branches are part of the Purkinje fibers that spread across the heart. The electrical signal reaches the Purkinje fibers and spreads across the entire heart to synchronize the heartbeat, explains the National Heart, Lung, and Blood Institute.