A 24-year-old athlete collapses during a marathon. ECG on recovery shows delta waves, short PR interval, and a wide QRS complex. He is asymptomatic between episodes. Electrophysiology study reveals an accessory pathway with anterograde effective refractory period (AERP) of 220 ms. This finding indicates:
- A High risk of sudden cardiac death; catheter ablation is recommended ✓
- B Low risk; reassure and allow unrestricted sport
- C High risk only if AERP is >250 ms
- D Medical management with flecainide is sufficient
Explanation
In Wolff-Parkinson-White (WPW) syndrome, the anterograde AERP of the accessory pathway (AP) during EPS is a critical risk stratification tool. An AERP ≤250 ms indicates a rapidly conducting AP capable of conducting AF impulses at high rates to the ventricle, potentially degenerating into ventricular fibrillation. An AERP ≤240 ms (some guidelines use 250 ms) represents high risk. This patient's AERP of 220 ms places him at high risk for SCD. Catheter ablation of the AP is curative and strongly recommended in symptomatic high-risk patients, particularly athletes. Long AERP (>250 ms) confers lower risk. Flecainide does not ablate the pathway.
Reference: Harrison's Principles of Internal Medicine, 21st ed.
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Written and medically reviewed by the StethoPrep medical team.