Final answer:
Cardioversion is a procedure that uses an electrical shock delivered in sync with the heart's QRS complex to depolarize the entire heart, allowing the SA node to reestablish a normal heart rhythm.
Step-by-step explanation:
An electrical shock synchronized with the QRS complex or ventricular beat that depolarizes the entire heart to allow the SA node to assume control is known as cardioversion. In the context of an electrocardiogram (ECG), the QRS complex represents the depolarization of the ventricles, which leads to their contraction during a heartbeat. Cardioversion is a medical procedure used to restore a normal heart rhythm when the heart is beating too fast or irregularly.
The procedure is typically performed by delivering a timed electrical shock to the heart, synchronized with the QRS complex on the ECG, to halt the abnormal electrical activity and allow the heart's natural pacemaker, the sinoatrial (SA) node, to regain control and reestablish a regular heartbeat. This is analogous to erasing incorrect electrical patterns on the heart and starting afresh with a normal rhythm.