The conduction system of the heart is a specialized network of cardiac cells responsible for generating and transmitting electrical impulses that regulate the heartbeat. It ensures that the atria and ventricles contract in a coordinated and rhythmic manner. Knowledge of this system is particularly important in critical care nursing because disturbances in cardiac conduction can produce arrhythmias, alter cardiac output, and become life-threatening. The sinoatrial (SA) node is the primary pacemaker of the heart. It is located in the upper wall of the right atrium near the opening of the superior vena cava. The SA node spontaneously generates electrical impulses at a normal rate of approximately 60–100 impulses per minute. These impulses spread through the atrial myocardium, causing both atria to contract and push blood into the ventricles. The SA node is influenced by the autonomic nervous system. Sympathetic stimulation increases heart rate, whereas parasympathetic stimulation through the vagus nerve decreases it. The electrical impulse then reaches the atrioventricular (AV) node, which is situated in the lower part of the right atrium near the interatrial septum. The AV node provides a brief delay in impulse transmission. This delay is essential because it allows the ventricles sufficient time to fill with blood after