A 55-year-old man develops palpitations and pre-syncope. 12-lead ECG shows delta waves, short PR interval (0.10 s), wide QRS, and a rapid irregular wide-complex tachycardia at 200 bpm during a spontaneous episode. He is hemodynamically stable. What is the drug of choice for acute pharmacological management?
- A IV adenosine
- B IV verapamil
- C IV procainamide ✓
- D IV amiodarone
Explanation
Wolff-Parkinson-White (WPW) syndrome with atrial fibrillation (pre-excited AF) is a life-threatening emergency. The irregular wide-complex tachycardia with delta waves indicates conduction down the accessory pathway. AV nodal blocking agents — adenosine, verapamil, diltiazem, digoxin — are absolutely CONTRAINDICATED as they can enhance conduction through the accessory pathway, accelerating ventricular rate to potentially fatal ventricular fibrillation. IV procainamide (IA antiarrhythmic) blocks conduction in both the AV node and accessory pathway and is the drug of choice for hemodynamically stable pre-excited AF. Cardioversion is used if unstable.
Reference: Harrison's Principles of Internal Medicine, 21st ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.