A client remains in diagnosed atrial fibrillation with rapid ventricular response despite prescribed pharmacological intervention. Synchronous cardioversion is scheduled to convert the rapid rhythm. Which action should the nurse plan to take to ensure safety and prevent complications of this procedure?

Cardioversion is similar to defibrillation with two major exceptions: the countershock is synchronized to occur during ventricular depolarization (QRS complex), and less energy is used for the countershock. The rationale for delivering the shock during the QRS complex is to prevent the shock from being delivered during repolarization (T wave), often termed the 'vulnerable period.' If the shock is delivered during this period, the resulting complication is ventricular fibrillation. It is crucial that the defibrillator is set on the 'synchronous' mode for a successful cardioversion. Cardioversion usually begins with 50 to 100 joules. Options 2 and 3 will not prevent complications.