In WPW with acute arrhythmia, which is NOT recommended due to risk of ventricular arrhythmias?

• A. Nodal blockers (adenosine, CCB)
• B. Procainamide
• C. Amiodarone
• D. Synchronized cardioversion

Answer: (A)

In WPW, an accessory conduction pathway can directly connect the atria to the ventricles, bypassing the AV node. During atrial fibrillation or other acute tachyarrhythmias, the ventricles may be driven very rapidly through that pathway. Drugs that slow the AV node (such as adenosine and calcium channel blockers) don’t affect the accessory pathway and can actually remove the AV node’s limiting effect, allowing even more impulses to reach the ventricles through the accessory pathway. This can push the ventricular rate to dangerously high levels and increase the risk of degeneration into ventricular fibrillation.

Therefore, blocking the AV node is not recommended in this scenario. Preferable acute management includes using a drug that prolongs the accessory pathway’s refractory period (like procainamide) or, if the patient is unstable, performing synchronized cardioversion. Amiodarone can be considered in some stable cases, but AV-nodal blockers are avoided.