The heartbeat is a complex, rhythmic process that pumps blood throughout the body. It begins with an electrical signal in the heart’s natural pacemaker, the sinoatrial (SA) node, located in the upper right atrium. This electrical impulse causes the atria (the heart’s two upper chambers) to contract, pushing blood into the ventricles (the two lower chambers). Next, the signal travels to the atrioventricular (AV) node, which briefly delays the impulse to ensure the ventricles have enough time