How does cardioversion differ from defibrillation in treating arrhythmias?

Cardioversion is a procedure that utilizes synchronized electrical shocks to restore normal heart rhythm, specifically targeting the R-wave of the QRS complex. This timing increases the likelihood of interrupting the arrhythmic circuit without inadvertently inducing ventricular fibrillation, which can occur if the shock is delivered during the vulnerable phase of the cardiac cycle.

In contrast, defibrillation is an emergency procedure used for life-threatening arrhythmias, particularly ventricular fibrillation and pulseless tachycardia, and is delivered in an unsynchronized manner. This means that the shock can occur at any point in the heart's electrical cycle, regardless of the R-wave, to brute-force a reset of the electrical system, allowing the heart to re-establish a normal rhythm.

Understanding this distinction is crucial for the appropriate treatment of various arrhythmias. Cardioversion's synchronization minimizes risks during the procedure, while defibrillation's lack of synchronization is necessary in critical, life-threatening situations.