What is the primary treatment for a patient with Wolf Parkinson White syndrome?

Treatment for Wolff-Parkinson-White Syndrome

Catheter ablation of the accessory pathway is the definitive treatment for symptomatic Wolff-Parkinson-White syndrome, with success rates exceeding 95% and should be considered first-line therapy for any patient who has experienced arrhythmias. 1, 2

Acute Management of Arrhythmias in WPW

Hemodynamically Unstable Patients

• Immediate direct-current cardioversion is indicated when tachyarrhythmias cause hemodynamic compromise, hypotension, or ventricular fibrillation. 3

Hemodynamically Stable Patients with Pre-excited Tachycardia

For stable antidromic AVRT or atrial fibrillation with pre-excitation:

• Ibutilide, procainamide, or flecainide are the preferred first-line agents as they slow conduction through the accessory pathway rather than the AV node. 1
• Type I antiarrhythmic agents or amiodarone may be administered intravenously in hemodynamically stable patients with preexcitation. 3

Critical Contraindications in Acute WPW with Pre-excitation

The following medications are absolutely contraindicated in WPW patients with tachycardia and ventricular preexcitation:

• Intravenous beta-blockers (metoprolol, propranolol, esmolol) 3
• Digitalis/digoxin 3
• Adenosine 3, 1
• Lidocaine 3
• Nondihydropyridine calcium channel antagonists (diltiazem, verapamil) 3

These AV nodal blocking agents can facilitate antegrade conduction along the accessory pathway during atrial fibrillation, resulting in acceleration of ventricular rate, hypotension, or ventricular fibrillation. 3 The FDA drug label for propranolol specifically warns that beta-blockade in WPW patients with tachycardia has been associated with severe bradycardia requiring pacemaker treatment. 4

Definitive Treatment: Catheter Ablation

Radiofrequency catheter ablation is the first-line definitive therapy for symptomatic WPW syndrome with the following characteristics:

• Success rates of 93-98.5% in experienced centers 1, 5
• Eliminates the risk of life-threatening arrhythmias by removing the anatomic substrate 5
• Should be considered after acute management in any patient who has experienced symptomatic arrhythmias 1, 2
• Recurrence of accessory pathway conduction occurs in only 5-8% of patients 5

Chronic Oral Maintenance Therapy (Bridge to Ablation)

If ablation is delayed or declined, chronic oral therapy may be used:

• Beta-blockers and calcium channel blockers are reasonable for oral chronic maintenance therapy in patients without active pre-excited arrhythmias. 3
• Propafenone is effective for preventing recurrent supraventricular arrhythmias in WPW, as it slows conduction and increases the effective refractory period of the accessory pathway in both directions. 6
• Class IA or IC antiarrhythmic agents can be used to slow accessory pathway conduction, either with or without AV nodal blocking agents for chronic management. 7

Important caveat: When using antiarrhythmic agents like propafenone or flecainide to prevent recurrent paroxysmal atrial fibrillation, AV nodal blocking drugs should be routinely coadministered because these compounds may increase the likelihood of 1:1 AV conduction during atrial flutter, leading to very rapid ventricular response. 3

Management of Asymptomatic WPW Pattern

For asymptomatic individuals with WPW pattern on ECG:

• Invasive electrophysiological study and possible ablation may be offered to well-informed asymptomatic individuals, particularly those in high-risk professions (pilots, commercial drivers, competitive athletes). 2
• Inducibility of arrhythmias during electrophysiological study predicts future symptomatic arrhythmias. 2
• The decision involves trading the very small risk of sudden death for a small immediate procedural risk. 2

Common Pitfalls to Avoid

1. Never administer AV nodal blocking agents during acute pre-excited tachycardia - this is the most dangerous error and can precipitate ventricular fibrillation. 3, 1

2. Do not mistake WPW for inferior myocardial infarction on ECG - the delta wave can create pseudo-infarction patterns. 8

3. Recognize that the short PR interval or broad QRS may not always be present - the delta wave is the most important diagnostic criterion. 8

4. After successful ablation, previous medication restrictions no longer apply as the anatomic substrate has been eliminated. 5