Final answer:
An electrical shock to restore normal heart rhythm directly affects the electrical function of the heart, resetting its activity and returning it to a regular beat pattern.
Step-by-step explanation:
Delivery of an electrical shock to restore a normal heart rhythm most directly affects the electrical function in the heart. During this procedure, the shock delivered to the heart resets the electrical activity, potentially stopping abnormal rhythms such as ventricular fibrillation or tachycardia, enabling the heart to regain a normal rhythm. The heart's electrical system is responsible for initiating and coordinating muscle contractions that pump blood throughout the body. This is critical since the heart is regulated by the sinoatrial (SA) node, which functions as the heart's natural pacemaker. Interference with this system can lead to arrhythmias, and an electrical shock can act as a restart, much like rebooting a malfunctioning computer.