Which scenario requires the use of synchronized cardioversion?

Synchronized cardioversion is a procedure used to treat certain abnormal heart rhythms, particularly those that are occurring in a patient who is unstable but still has some level of cardiac output. This involves delivering a shock to the heart that is timed to coincide with a specific point in the cardiac cycle, ensuring that the shock is applied when the heart is ready to respond and thereby restoring a normal rhythm.

In the case of stable atrial fibrillation, this rhythm can sometimes be effectively treated by synchronized cardioversion, particularly if the patient is experiencing symptoms or if there's a need to convert the rhythm for clinical reasons. Atrial fibrillation can lead to rapid ventricular rates and can cause hemodynamic instability, which may warrant intervention. However, this treatment is typically considered more in the context of symptoms being present; in stable scenarios, other methods like rate control or anticoagulation might be preferred, but the ability to use synchronized cardioversion when necessary is a key point.

Unstable bradycardia would typically require different measures, such as administration of atropine or pacing, rather than synchronized cardioversion. Asystole and pulseless electrical activity are not shockable rhythms and would necessitate different resuscitation protocols, hence they don't apply in