WPW pattern vs Atrial fibrillation with WPW
How to tell WPW pattern and Atrial fibrillation with WPW apart when a board question makes them look alike.
WPW pattern is baseline delta wave; AF with WPW is irregular wide tachycardia where AV nodal blockers can be dangerous.
Side by side
Baseline preexcitation: short PR interval, delta wave, and widened QRS from an accessory pathway.
Dangerous irregular wide-complex tachycardia in WPW when AF conducts rapidly through the accessory pathway.
Accessory pathway bypasses the AV node and preexcites ventricular myocardium.
AF plus accessory conduction can produce very rapid ventricular rates because the AV node is not the only gatekeeper.
Sinus rhythm with short PR and delta wave points WPW pattern.
Irregular wide-complex tachycardia with varying QRS morphology and WPW history points preexcited AF.
The trap
Do not treat preexcited AF like ordinary AF; blocking the AV node can favor accessory pathway conduction.
Watch it explained
The repair move
For WPW, separate baseline preexcitation from the emergency rhythm it can enable.
Try a free question
CoreA young patient has palpitations. Baseline ECG shows a short PR interval, widened QRS, and slurred upstroke of the QRS complex. Which pattern is most likely?
Show answer and explanation
Answer: A. WPW preexcitation pattern. WPW pattern shows preexcitation through an accessory pathway with short PR interval and delta wave.
Why the other choices are tempting
- B. Atrial fibrillation lacks organized P waves and is irregularly irregular.
- C. Mobitz I has progressive PR prolongation.
- D. Long QT syndrome has prolonged repolarization, not short PR/delta wave.
- E. Complete heart block has AV dissociation.
Flashcards
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What is the fastest separator for WPW pattern vs Atrial fibrillation with WPW?
WPW pattern is baseline delta wave; AF with WPW is irregular wide tachycardia where AV nodal blockers can be dangerous.
What clue should make you choose WPW pattern?
Baseline preexcitation: short PR interval, delta wave, and widened QRS from an accessory pathway.
Quick answers
What is the fastest way to tell WPW pattern from Atrial fibrillation with WPW?
WPW pattern is baseline delta wave; AF with WPW is irregular wide tachycardia where AV nodal blockers can be dangerous.
What is the key clue for WPW pattern?
Baseline preexcitation: short PR interval, delta wave, and widened QRS from an accessory pathway.
What is the key clue for Atrial fibrillation with WPW?
Dangerous irregular wide-complex tachycardia in WPW when AF conducts rapidly through the accessory pathway.
What is the common trap with WPW pattern vs Atrial fibrillation with WPW?
Do not treat preexcited AF like ordinary AF; blocking the AV node can favor accessory pathway conduction.