A 24-year-old woman with recurrent paroxysmal SVT is found to have a delta wave, short PR interval, and wide QRS on resting ECG. She has a history of syncope during episodes. EP study reveals a left lateral accessory pathway with shortest pre-excited RR interval of 210 ms during atrial fibrillation. The MOST appropriate management is:
- A Catheter ablation of the accessory pathway ✓
- B Rate control with verapamil and digoxin
- C Flecainide as long-term antiarrhythmic prophylaxis
- D Observation; no treatment as the pathway is benign given normal echo
Explanation
Wolff-Parkinson-White (WPW) syndrome with pre-excited AF is potentially life-threatening; rapid conduction via the accessory pathway (bypassing the AV node's protective delay) can lead to ventricular fibrillation. A shortest pre-excited RR interval <250 ms during pre-excited AF indicates a high-risk pathway (capable of conducting rapidly enough to cause VF). The presence of syncope further identifies high risk. Catheter radiofrequency ablation of the accessory pathway is the definitive treatment and is recommended in symptomatic patients and those with high-risk pathways. Verapamil and digoxin are contraindicated in pre-excited AF (they slow AV nodal conduction but accelerate accessory pathway conduction). Flecainide may be adjunct but ablation is curative.
Reference: Harrison's Principles of Internal Medicine, 21st ed.
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Written and medically reviewed by the StethoPrep medical team.