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Wolff-Parkinson-White (WPW) Syndrome

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Wolff-Parkinson-White (WPW) Syndrome
Tricia Beatty
Basics
Alert
  • Supplemental oxygen
  • Monitor
  • Synchronized cardioversion if signs of instability (1)
  • Controversies:
    • Prehospital use of adenosine:
      • Stable patients should be treated with adenosine.
      • Unstable patients should undergo cardioversion.
    • Catheter radiofrequency ablation:
      • Use in asymptomatic children and adults is controversial.
      • Risks and benefits of treating or not treating should be weighed carefully.
Description
The presence of paroxysmal arrhythmias in a patient with ventricular preexcitation caused by one or more accessory pathways (2).
Epidemiology
Incidence
New cases are diagnosed in the general population at a rate of 0.004% per year.
Prevalence
  • 0.1–0.3% of general population affected
  • No difference in the athletic population
  • Predominant gender: Male > Female (3)
Risk Factors
Genetics
  • 3–4% of the cases are familial.
  • Inheritance pattern is autosomal dominant (2).
Etiology
  • Type A (orthodromic) is the most common (95%).
    • Antegrade limb is the atrioventricular (AV) nodal conduction system, and the retrograde limb is the accessory pathway.
    • A circuit is created that potentiates reentrant tachycardia.
  • Type B (antidromic):
    • Less common than type A
    • The circuit operates in the opposite direction.
  • Risks associated with reentrant tachycardia:
    • Development of atrial fibrillation in 20–25% of cases
    • Degeneration into ventricular fibrillation
    • Sudden cardiac death (4)
Commonly Associated Conditions
  • Ebstein anomaly
  • Ventricular septal defect
  • Mitral valve prolapse
  • Hypertrophic cardiomyopathy
  • Atrial septal defect
  • Anomalous pulmonary venous return
  • Corrected transposition of the great arteries
  • Aortic regurgitation
  • Tetralogy of Fallot
  • Tricuspid atresia
  • Neoplasm (rhabdomyosarcoma)
  • Polycystic kidney disease
  • Rheumatic heart disease
  • Genetic abnormality (PRKAG2 gene) (4)
Diagnosis
  • Wolff-Parkinson-White (WPW) syndrome should be considered as the underlying etiology in all cases of tachydysrhythmias.
  • The diagnosis should be based on the characteristic ECG findings once the patient has converted to a sinus rhythm.
  • Electrophysiology studies to assess for reentrant tachydysrhythmia inducibility (2)
History
  • Asymptomatic
  • Palpitations
  • Chest pain
  • Dyspnea
  • Dizziness
  • Weakness
  • Fatigue
  • Nausea
  • Light-headedness
  • Syncope
Physical Exam
  • Abnormal heart rate:
    • Narrow QRS complex:
      • Rapid and regular [supraventricular tachycardia (SVT)]
      • Irregular (atrial fibrillation)
    • Wide QRS complex:
      • Ventricular fibrillation
      • Ventricular tachycardia
  • Signs of instability:
    • Chest pain
    • Hypotension
    • Change in mental status
    • Rales
Diagnostic Tests & Interpretation
Lab
  • CBC
  • Thyroid function test
  • Basic metabolic panel
Diagnostic Procedures/Surgery
  • ECG (2):
    • PR interval <120 ms during sinus rhythm in adults and <90 ms in children
    • Delta wave: Slurring of initial portion of the QRS complex
    • QRS duration >120 ms in adults and >90 ms in children
    • Secondary ST- and T-wave changes
  • Echocardiogram: Structural heart disease
  • Holter monitor or external event monitor: Useful in documenting paroxysmal tachydysrhythmia
  • Electrophysiology study:
    • Elucidate the accessory pathway(s)
    • Determine inducibility of AV reciprocating tachycardia (AVRT).
    • Indications:
      • All competitive athletes or high-risk recreation athletes
      • Patients with high-risk professions (pilot, truck or bus driver, etc.)
      • All children >10 yrs of age
Differential Diagnosis
  • AV nodal reentry SVT
  • Atrial fibrillation
  • Ventricular fibrillation
  • Ventricular tachycardia (4)

P.627


Treatment
ED Treatment
  • Stable patients with narrow complex, regular tachycardia (2):
    • Vagal maneuvers such as a Valsalva
    • Right carotid artery massage for no more than 10 s: Auscultate the artery 1st for a bruit, which would be a contraindication to right carotid artery massage.
    • Fluid replacement and Trendelenburg position if the patient has mild hypotension
    • Pharmacologic conversion if carotid massage fails: Adenosine; monitor for development of atrial fibrillation.
  • Stable patients with irregular wide-complex tachycardia:
    • Procainamide is the drug of choice.
    • Never use calcium channel blockers, β-blockers, or digoxin. These medications block the AV node and lead to conduction occurring exclusively down the faster accessory pathway, resulting in fatal ventricular dysrhythmias.
Medication
  • Adenosine: 6-mg rapid IV push; if ineffective, repeat with 12 mg; children: 0.1 mg/kg rapid IV push
  • Procainamide: 6–13 mg/kg IV at 0.2–0.5 mg/kg/min until arrhythmia controlled, up to a total dose of 1,000 mg, then 2–6 mg/min (2)
Additional Treatment
Cather radiofrequency ablation (1):
  • Indications:
    • Symptomatic patients
    • All competitive athletes
    • Patients engaged in high-risk professions or recreational activities
  • Efficacy:
    • 95%
    • Recurrent accessory pathway conduction is usually successfully ablated during a 2nd session.
  • Complications (2–4%):
    • Complete heart block
    • Cardiac tamponade
    • Vascular access
    • Catheter manipulation
In-Patient Considerations
Initial Stabilization
Unstable patients:
  • Synchronized cardioversion starting with 50 J/min
  • Increase incrementally until sinus rhythm is restored
Admission Criteria
  • Patients with signs of instability require admission to a monitored bed.
  • Failure of outpatient therapy for continuous pharmacologic control or ablation
Discharge Criteria
  • Most patients will be stable and can be discharged once converted to sinus rhythm.
  • Follow-up should be arranged with a cardiologist.
Ongoing Care
Return-to-play guidelines:
  • 3–6 mos after catheter ablation
  • Asymptomatic
  • Negative EPS(no inducible accessory pathway)
References
1. Tischenko A, Fox D, Yee R, et al. When should we recommend catheter ablation for patients with the Wolff-Parkinson-White syndrome? Current Opinion in Cardiology. 2008;23:32–37.
2. Sethi KK, Dhall A, Chadha DS, et al. WPW and Preexcitation Syndromes. Supplement of JAPI. 2007;55:10–15.
3. Heidbuchel H, Panhuyzen-Goedkoop N, Corrado D, et al. Recommendations for participation in leisure-time physical activity and competitive sports in patients with arrhythmias and potentially arrhythmogenic conditions, Part I: Supraventricular arrhythmias and pacemakers. European Journal of Cardiovascular Prevention and Rehabilitation. 2006;13:475–484.
4. Lee KW, Badhwar N, Scheinman MM. Supraven-tricular tachycardia–part I. Curr Probl Cardiol. 2008;33:467–546.
Additional Reading
Brembilla-Perrot, Beatrice. When and how to assess an asymptomatic ventricular pre-excitation syndrome? Archives of Cardiovascular Disease. 2008;101:407–411.
Lee KW, Badhwar N, Scheinman MM. Supraven-tricular Tachycardia-Part II: History, Presentation, Mechanism, and Treatment. Curr Probl Cardiol. 2008;33:557–622.
Saxena A, Chang C, Wang S. Wolff-Parkinson-White Syndrome in Athletes. Current Sports Medicine Reports. 2006;5:254–257.
Shah CP, Thakur RK, Xie B, et al. Clinical approach to wide QRS complex tachycardias. Emerg Med Clin North Am. 1998;16:331–360.
Surawicz B, Childers R, Deal B, et al. AHA/ACCF/HRS Recommendations for the Standardization and Interpretation of the Electrocardiogram, Part III: Intraventricular Conduction Disturbances. JACC. 2009;53:976–981.
Wolf-Parkinson-White (WPW) Syndrome, Atrioventricular Reentrant Tachycardia. Current Problems in Cardiology. September 2008:504–522.
Xie B, Thakur RK, Shah C, et al. Emergency management of cardiac arrhythmias. Clinical differentiation of narrow QRS complex tachycardias. Emerg Clin North Am 1998;16:295–330.
Codes
ICD9
426.7 Anomalous atrioventricular excitation


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