Wolff–Parkinson–White syndrome: Difference between revisions

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Background

  • Suspect in any pt w/ ventricular rate >300

Orthodromic Type

  • More common type occuring ~95% of the time
  • Accessory pathway (Kent bundles) is used for retrograde reentry conduction
  • QRS narrow (delta wave absent)
  • May see ST depression, TWI
  • Rate 150-250 bpm

Antidromic Type

  • Least common type occuring ~5% of the time
  • Accessory pathway used for anterograde conduction
  • QRS wide, delta wave present

Atrial Fibrillation and Flutter[1]

  • Atrial fibrillation in up to 20% of pts with WPW
    • Irregular rhythym, wide QRS complexes
    • Changing QRS complexes in shape and morphology
    • Axis remains stable as opposed to polymorphic VT
  • Atrial flutter in ~7% of pts with WPW
    • Similar features to atrial fibrillation with WPW
    • Except regular rhythym
    • Easily mistaken for regular rate VT
  • Treatment with AV nodal blocking agents (adenosine, BBs, CCBs, amiodarone, digoxin) may incite ventricular fibrillation or ventricular tachycardia
  • "Manifest WPW" = degeneration into VT or VF

Diagnosis

Although the ECG and an electrophysiology study are diagnostic, the characteristic features are not always seen on ECG

  1. Short PR interval - <0.12sec
    1. Due to loss of normal AV node conduction delay
    2. Differentiate from premature junctional complex
  2. Delta wave / slurred upstroke
    1. Due to early activation of ventricular myocardium
  3. QRS duration > 0.10 sec
    1. Represents a fusion beat
  4. Dominant R wave in V1, Type A WPW
    1. Left sided accessory pathway
  5. Dominant S wave in V1, Type B WPW
    1. Right sided accessory pathway
  6. Tall R waves in V1-V3 with T wave inversion
    1. Mimic RVH
  7. "Negative" delta waves in III and aVF
    1. Appear as pseudo-infarct Q waves
    2. Mimics prior inferior infarct

Treatment

Orthodromic

Treat like paroxysmal SVT'

  • Unstable
    • Cardioversion (synchronized)
    • Adult: 50-100 J
    • Peds: 0.5-2 J/kg
  • Stable
    • CCBs, BBs, procainamide, or adenosine
    • Procainamide safe irrespective of type of pathway conduction

Antidromic

Treat like ventricular tachycardia

  • Synchronized cardioversion
    • Adult: 50-100 J
    • Peds: 0.5-2 J/kg
    • Procainamide: 17mg/kg IV over 30min (up to 50mg/kg or 50% widening of QRS complex)
    • Amiodarone with 'ABCD' drugs ie adenosine, BBs, CCBs, digoxin
  • Wide-complex, irregular (presumed preexcited A-fib)
    • Unsynchronized cardioversion (200J)

Atrial Fibrillation and Atrial Flutter

  • Stable - synchronized cardioversion, 100 - 200 J
  • Unstble - procainamide or ibutilide
  • Avoid AV nodal blocking agents

Disposition

  • Discharge:
    • Consider if dysrhythmia was easily terminated and can arrange outpt EP study with poss RF catheter ablation
    • C/w with cardiologist regarding outpt beta-blockers vs. more potent medications (amiodarone, sotalol, flecainide, etc.)
  • Admit or transfer to center with electrophys[2]:

See Also

WPW with AFIB

Sources

  1. Burns E. Wolff-Parkinson-White Syndromes. Life in the Fast Lane. http://lifeinthefastlane.com/ecg-library/pre-excitation-syndromes/.
  2. Ellis CR et al. Wolff-Parkinson-White Syndrome Treatment & Management. eMedicine. Dec 4, 2015. http://emedicine.medscape.com/article/159222-treatment#showall.