Table Of Contents

Wolff-Parkinson-White Syndrome (WPW)

General

• Congenital condition characterized by intermittent tachycardias & premature ventricular excitation
• Arise from an accessory pathway known as the bundle of Kent
• Pathophysiology
  • Presence of an accessory electrical pathway (Bundle of Kent) leading to premature ventricular excitation.
  • Tachycardia can be caused by atrial fibrillation/flutter or (Atrioventricular Reentrant Tachycardia - AVRT).

Clinical Presentation

• Often asymptomatic unless an arrhythmia develops.

  <aside> 💡

  WPW Pattern 🆚 WPW syndrome

  • WPW pattern = asymptomatic
  • WPW syndrome = associated with arrhythmias (Ventricular Tachycardia)

  

  </aside>

Wolff-Parkinson-White (WPW) syndrome and pattern

Diagnosis

• ECG Findings

  • WPW
    • Shortened PR interval
    • presence of a delta wave.
  • AVRT (See below)

  ECG patterns in Wolff-Parkinson-White syndrome	Delta wave present	QRS complex width	AV node dependence	Acute treatment
  Sinus rhythm	Yes	Wide	Yes	NA
  AV reentrant tachycardia	No	Usually narrow	Yes	Vagal maneuvers or adenosine*
  Preexcited atrial fibrillation	Intermittently	Wide	No**	Procainamide*

  Immediate synchronized cardioversion is indicated for hemodynamic instability.

  **Absence of AV node dependence creates risk of extremely high ventricular rates.

• Other ECGs

Treatment

1. Unstable Arrhythmia

   • Synchronized Cardioversion

2. Orthodromic AVRT (narrow QRS)

   • Vagal maneuvers
   • Adenosine

   <aside> ⛔ Both C.I. with irregular rhythm [eg, AF] → because AV-node blockers promote more conduction through the accessory pathway → ↑ rapid ventricular response.

   </aside>

3. **Antidromic AVRT or Atrial Fibrillation (wide complex)**

   • Procainamide (First-line)
   • Ibutilide

4. Definitive Therapy

   • Catheter ablation of the accessory pathway
     • First-line for refractory cases

<aside> ❓

What is the recommended temporary management for a hemodynamically stable Wolff-Parkinson-White syndrome patient with atrial fibrillation?

• Answer </aside>

Atrioventricular Re-entrant Tachycardia (AVRT)

• A tachyarrhythmia caused by an accessory pathway that creates a reentrant circuit with the AV node

Wolff-Parkinson-White syndrome is a common cause of AVRT but they are not synonymous WPW is an ECG pattern based on an aberrant pathway, AVRT is a complication in form of arrhythmia.

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ECG findings in AVRT

Orthodromic and antidromic AVRT

• Details

<aside> 💡

During an attack of tachyarrythmia → delta waves and delta waves may not be present!

</aside>

<aside> 🎁

AVRT is caused by an accessory pathway, whereas in AVNRT there are two functional pathways within the AV node.

• Explanation with illustrations </aside>

Brugada Syndrome

General

• Autosomal dominant genetic condition.
• Caused by defective cardiac voltage-gated sodium channels
• Most commonly seen in adults males of southeast Asian descent.
• Associated with an increased risk of ventricular arrhythmias and sudden cardiac death.

Diagnosis

• ECG Findings

Management

• Implantable Cardioverter-Defibrillator (ICD) placement

Congenital Long QT Syndrome (LQTS)