What is the internal pacemaker of the heart?

The internal pacemaker of the heart is the sinoatrial (SA) node. This structure is located in the right atrium and is primarily responsible for initiating and regulating the heartbeat. The SA node generates electrical impulses that spread through the atria, causing them to contract and push blood into the ventricles. This electrical activity sets the pace for the entire heart rhythm, which is why it is often referred to as the primary pacemaker.

The SA node's position and its intrinsic ability to create impulses at a regular frequency enable it to effectively maintain the heart’s rate under normal physiological conditions. In a healthy heart, the SA node generates impulses at a rate of about 60 to 100 beats per minute, which aligns with the typical resting heart rate for adults.

Other structures within the heart, such as the atrioventricular (AV) node and the Purkinje fibers, play important roles in the conduction system but do not serve as the primary pacemaker. The AV node acts as a gatekeeper, slowing down the impulse before it enters the ventricles, while the Purkinje fibers are responsible for conducting the impulse rapidly throughout the ventricles to ensure they contract efficiently. The coronary sinus, on the other hand, is a large vein