Wolff–Parkinson–White syndrome
Revision as of 13:53, 22 March 2016 by Ostermayer (talk | contribs) (Text replacement - "Category:Cards" to "Category:Cardiology")
Background
- Suspect in any pt w/ ventricular rate >300
Types
- Orthodromic (~95%)
- Accessory pathway (Kent bundles) is used for retrograde reentry conduction
- QRS narrow (delta wave absent)
- May see ST depression, TWI
- Rate 150-250 bpm
- Accessory pathway (Kent bundles) is used for retrograde reentry conduction
- Antidromic (~5%)
- Accessory pathway used for anterograde conduction
- QRS wide, delta wave present
- Accessory pathway used for anterograde conduction
Diagnosis
- Characteristic features not always seen on ECG
- Short PR interval - <0.12sec
- Due to loss of normal AV node conduction delay
- Differentiate from premature junctional complex
- Delta wave / slurred upstroke
- Due to early activation of ventricular myocardium
- QRS duration > 0.10 sec
- Represents a fusion beat
Treatment
- Orthodromic
- Treat like paroxysmal SVT:
- Unstable
- Cardioversion (synchronized)
- Adult: 50-100 J
- Peds: 0.5-2 J/kg
- Cardioversion (synchronized)
- Stable
- CCBs, BBs, procainamide, or adenosine
- Procainamide safe irrespective of type of pathway conduction
- CCBs, BBs, procainamide, or adenosine
- Unstable
- Treat like paroxysmal SVT:
- 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
- Contraindicated: 'ABCD' drugs ie adenosine, BBs, CCBs, digoxin
- Synchronized cardioversion
- Treat like ventricular tachycardia:
- Wide-complex, irregular (presumed preexcited A-fib)
- Unsynchronized cardioversion (200J)
Disposition
- Admit:
- Pts with chest pain, CHF, electrolyte imbalance, or required cardioversion
- Discharge:
- Consider if dysrhythmia was easily terminated and can arrange outpt EP study