A 50-year-old man presents with palpitations. ECG shows an irregularly irregular wide-complex tachycardia with varying QRS morphology and a rate of 220 bpm. The patient has a known history of WPW syndrome with delta waves on baseline ECG. Which drug is contraindicated in this situation?
- A IV procainamide
- B IV verapamil ✓
- C IV amiodarone
- D IV ibutilide
Correct answer: B. IV verapamil
Explanation
In WPW with AF, the accessory pathway conducts rapidly and unpredictably. Verapamil (and other AV nodal blockers like digoxin and beta-blockers) block the AV node but may paradoxically accelerate conduction down the accessory pathway, increasing ventricular rate and risking VF. Procainamide and ibutilide slow accessory pathway conduction. This differs from the existing WPW question which asks about management choice.
Reference: Zipes and Jalife Cardiac Electrophysiology, 7th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.