Wolf-Parkinson-White (quick review)

19 Oct

WPW = pre-excitation accessory pathway syndrome

Upsloping delta wave on QRS complex causing a shortened PR interval.

85% of SVT with WPW are narrow QRS complexes with AV retrograde conduction and accessory bundle antegrade conduction.

The accessory pathway is called a Kent Bundle and is tissue directly linking atria to the ventricles. 

There are three types of WPW, A, B, C, depending on anatomic location of the pathway.

A wide complex SVT from WPW should be treated like Vtach.

  • The wide complex is caused by a short refractory period of the accessory pathway.
  • Blocking the AV node is these cases can put the patient into Ventricular fibrillation (unopposed transmission through accessory pathway)
  • do NOT give B-blockers, calcium channel blockers or adenosine in wide complex rhythms.
  • Give Procainamine or synchronized cardioversion.
  • Procainamide prolongs the refractory period of the accessory pathway, not just the AV node.

Narrow complex WPW, (orthodromic AV reciprocating tachycardia) can be treated like SVT with AV node blocking agents.

Definitive treatment of WPW is ablation.

Submitted by C. Stokes.

References: Tintinalli’s Emergency Medicine: A Comprehensive Study Guide. 7th Edition; Rosen’s Emergency Medicine. (2010) 1235-1239; picture

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