Wolff–Parkinson–White syndrome

Background

usually 150- 300 bpm

Diagnosis

1. short PR interval <0.12 sec
2. QRS duration >0.10 sec
3. delta wave/ slurred upstroke
4. short PR interval due to loss of normal AV node conduction delay
5. delta wave due to early activation of vent myocardium

Orthodromic Tachycrd

1. the accessory path used for retrograde reentry conduction and AV node used for anterograde conduction. QRS is narrow, delta wave absent
2. TX with CA channel blockers, beta blockers, procainamide, adenosine.
3. Cardiovert (sync) if unstable with 50- 100J (0.5- 2J/kg for kids)

Antidromic Tachycrd

1. access path used for anterograde conduction and AV node used for retrograde reentry.
2. do not use beta blckrs of ca chnnl blckrs since will block down AV node only and not acc path and will actually speed up arrhythmia.
3. TX with procainamide- 100mg q10 min until arrhrythmia terminated or max dose of 1000mg given. If no success, then cardiovert.
4. Cardiovert (sync) if unstable with 50- 100J (0.5- 2J/kg for kids)

DDX

1. idiopathic
2. hypertrophic cardiomyopathy
3. transposition of great vesses
4. endocardial fibroelastosis
5. mitral valve prolapse
6. tricuspid atresia
7. ebstein disease

Disposition

Admission:

1. admit if cardioverted, chest pain, CHF, electrolyte imbalance.
2. if easily terminated can be discharged with outpt electrophysiological study