Wolff–Parkinson–White syndrome
Background
- Orthodromic (~95%)
- Accessory pathway used for retrograde reentry conduction
- QRS narrow, delta wave absent
- May see ST depression, TWI
- Rate 150-250 bpm
- Accessory pathway used for retrograde reentry conduction
- Antidromic (~5%)
- Accessory pathway used for anterograde conduction
- QRS wide, delta wave present
- Accessory pathway used for anterograde conduction
- Atrial fibrillation seen in 10-30%
Diagnosis
- Characteristic features not always seen on ECG
- Short PR interval - <0.12sec
- Due to loss of normal AV node conduction delay
- Delta wave / slurred upstroke
- Due to early activation of vent myocardium
- QRS duration > 0.10 sec
- Due to delta wave
DDX
- idiopathic
- hypertrophic cardiomyopathy
- transposition of great vesses
- endocardial fibroelastosis
- mitral valve prolapse
- tricuspid atresia
- ebstein disease
Treatment
- Orthodromic
- Treat like paroxysmal SVT
- CCBs, BBs, procainamide, or adenosine
- Procainamide safe irrespective of type of pathway conduction
- Cardiovert (sync) if unstable
- Adult: 50-100 J
- Peds: 0.5- 2 J/kg
- Treat like paroxysmal SVT
- Antidromic
- Procainamide 100mg q10min until disrhythmia terminated or max dose (1000mg)
- Amiodarone
- Cardioversion
- Adult: 50-100 J
- Peds: 0.5- 2 J/kg
- Contraindicated: CCBs, BBs, digoxin, adenosine
- Irregular tachycardia
- Treat like antidromic
Disposition
- Admission:
- Cardioverted, chest pain, CHF, or electrolyte imbalance
- Discharge
- If easily terminated d/c w/ outpt EP study