How does cardioversion differ from a normal defibrillation shock?

Cardioversion differs from a standard defibrillation shock primarily in its synchronization with the heart's electrical activity. In cardioversion, the shock is delivered in a way that is timed to coincide with a specific point in the cardiac cycle, particularly the R wave of the QRS complex, to avoid inducing ventricular fibrillation. This synchronization makes cardioversion a preferred approach for treating certain arrhythmias, such as atrial fibrillation, since it can restore normal rhythm safely.

In contrast, defibrillation, which is used in life-threatening situations like ventricular fibrillation or pulseless ventricular tachycardia, delivers an unsynchronized shock intended to reset the heart's electrical activity without regard to the cardiac cycle. Thus, the method and timing of the shock are crucial to the effectiveness and safety of cardioversion in treating arrhythmias.