Final answer:
Immediate electrical cardioversion is the treatment of choice for unstable atrial fibrillation in patients with WPW syndrome, as it can restore a normal sinus rhythm quickly and effectively. Avoidance of certain medications is important as they may enhance conduction through the accessory pathway and worsen the condition.
Step-by-step explanation:
The treatment of choice for unstable atrial fibrillation in patients with Wolff-Parkinson-White (WPW) syndrome is immediate electrical cardioversion. WPW syndrome is characterized by the presence of an accessory pathway that can lead to rapid heart rates. In the case of atrial fibrillation, this accessory pathway can cause particularly high ventricular rates that may degenerate into ventricular fibrillation, a life-threatening condition. Therefore, the main goal is to restore a normal sinus rhythm as quickly as possible.
Defibrillation, which delivers a therapeutic dose of electrical energy to the heart, effectively stops the heart temporarily so that the sinoatrial (SA) node can re-establish a normal conduction cycle. In contrast to atrial fibrillation, which can be serious but not immediately life-threatening as long as the ventricles continue to pump blood, ventricular fibrillation requires immediate defibrillation as it is a medical emergency due to ineffective pumping of the ventricles.
Other treatment options, such as medication, are generally avoided in the acute setting because drugs that typically slow conduction through the AV node can actually enhance conduction through the accessory pathway, potentially worsening the situation. Thus, electrical cardioversion is the preferred method to rapidly and effectively treat unstable atrial fibrillation in the setting of WPW syndrome.