We discussed a case about a previously healthy young man who presented with acute dizziness, SOB, and palpitations due to tachyarrhythmia from Wolff-Parkinson-White Syndrome.

WPW pattern: preexcitation and absence of symptomatic arrhythmia-

WPW syndrome: preexcitation + symptomatic arrhythmia involving the accessory pathway 

The accessory pathway can conduct bidirectionally (anterograde or retrograde)

EKG: delta wave (slurred and broad upstroking of the QRS complex)

Several tachyarrhythmias can be related to WPW (e.g. afib, AVRT)

• Orthodromic: anterograde via AV node; retrograde via accessory pathway
  • Treatment: synchronized cardioversion (if unstable); start w/ vagal maneuvers & adenosine (if stable)

• Antidromic: anterograde via accessory pathway; retrograde via AV node
  • Treatment: synchronized cardioversion (if unstable); start w/ vagal maneuvers & consider procainamide (if stable)
  • Unmitigated conduction via anterograde accessory pathway can cause unstable rhythm that degenerates to vtach

If chronic and stable: 1st line therapy is ablation