EKG

Wolff-Parkinson-White Syndrome

search

Wolff-Parkinson-White Syndrome, Wolff-Parkinson-White, WPW Syndrome

  • Definition
  1. Arrhythmia associated with AV bypass tract
  2. Subtype of Atrioventricular Reciprocating Tachycardia (AVRT) distinguised by its delta wave
  • Epidemiology
  1. Prevalence: 2 per 1000 general population
  • Pathophysiology
  1. Atrioventricular bypass tract
    1. Circumvents normal PR interval delay (up to 0.2 sec)
    2. Allows for ventricular pre-excitation
  2. Predisposes to arrhythmia
    1. Reentrant Paroxysmal Supraventricular Tachycardia
    2. Paroxysmal Atrial Fibrillation
  • Findings
  • EKG changes
  1. Precautions
    1. WPW EKG Findings may be variably present
    2. Classic findings are more prominent with Valsalva Maneuver (or other increased vagal tone)
  2. Narrow PR interval
    1. Due to pre-excitation of ventricle
    2. Look closely for Delta wave when a narrow PR interval is identified on EKG
  3. Delta wave
    1. Slurred upstroke of QRS (hockey stick appearance)
    2. Wide QRS related to delta wave (to extent that PR interval is narrowed)
  4. Other changes
    1. ST and T Wave deflections that are discordant (opposite) to the QRS deflection
  • Differential Diagnosis
  1. Right or Left Bundle Branch Block (wide complex)
  2. Myocardial Infarction (Q Wave when QRS negative)
  • Precautions
  1. Agents to avoid in WPW (may accelerate arrhythmia via accessory path)
    1. Adenosine
    2. Beta Blockers (e.g. Metoprolol)
    3. Calcium Channel Blockers (e.g. Verapamil, Diltiazem)
    4. Digoxin (Lanoxin)
  2. Have a high index of suspicion in young patients with Syncope
    1. WPW may be present despite an absence of Short PR Interval and a Delta Wave
  3. Sinus Tachycardia can still occur with all of the typical reasons seen in patients without WPW
    1. Consider dehydration, infection, Pulmonary Embolism in the differential in a patient with WPW and Tachycardia
  • Complications
  1. Atrioventricular Re-Entry Tachycardia (AVRT)
    1. Rates are typically very high (200-300 bpm)
  2. Atrial Fibrillation (20% of WPW patients)
  3. Atrial Flutter (7% of WPW patients)
  4. Ventricular Tachycardia or Ventricular Fibrillation
  5. Sudden Cardiac Death
  • References
  1. Braude, Swadron and Orman et. al. in Majoewsky (2012) EM:RAP 12(7): 1-2
  2. Goldberger (1999) Clinical Electrocardiography, p 127-8
  3. Grauer (2001) 12 Lead EKG, p. 27
  4. Joshi and Dermark (2016) Crit Dec Emerg Med 30(8):3-12