Wolff–Parkinson–White syndrome: Difference between revisions
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==Diagnosis== | ==Diagnosis== | ||
''Although the ECG and an | ''Although the ECG and an electrophysiology study are diagnostic, the characteristic features are not always seen on ECG'' | ||
#Short PR interval - <0.12sec | #Short PR interval - <0.12sec | ||
##Due to loss of normal AV node conduction delay | ##Due to loss of normal AV node conduction delay | ||
Revision as of 00:33, 27 March 2016
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
Diagnosis
Although the ECG and an electrophysiology study are diagnostic, the characteristic features are 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
- Dominant R wave in V1, Type A WPW
- Left sided accessory pathway
- Dominant S wave in V1, Type B WPW
- Right sided accessory pathway
- Tall R waves in V1-V3 with T wave inversion
- Mimic RVH
- "Negative" delta waves in III and aVF
- Appear as pseudo-infarct Q waves
- Mimics prior inferior infarct
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
- 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[1]:
- Pts with chest pain, CHF, electrolyte imbalance, or required cardioversion
- Syncope
- Uncertain dx (wide-complex tachycardia)
- Significant associated structural heart disease (MVP, cardiomyopathy)
- Family hx of Sudden cardiac death
- Atrial flutter or atrial fibrillation
See Also
Sources
- Burns E. Pre-excitation Syndromes. Life in the Fast Lane. http://lifeinthefastlane.com/ecg-library/pre-excitation-syndromes/.
- ↑ Ellis CR et al. Wolff-Parkinson-White Syndrome Treatment & Management. eMedicine. Dec 4, 2015. http://emedicine.medscape.com/article/159222-treatment#showall.