Management of accessory pathway tachycardia and pre-excited atrial fibrillation
THE CONTEXT
In Wolff–Parkinson–White syndrome, an accessory pathway supports tachycardia and can permit dangerously rapid ventricular activation during atrial fibrillation.
Acute tachycardia and pre-excited atrial fibrillation
•
Carotid sinus pressure or intravenous adenosine can terminate the tachycardia.
•
During atrial fibrillation, an accessory pathway capable of rapid antegrade conduction can produce a dangerously rapid ventricular rate because it lacks the rate-limiting properties of the atrioventricular node.
•
Pre-excited atrial fibrillation can cause collapse, syncope or death and requires emergency treatment, usually DC cardioversion.
Definitive treatment and drug precautions
•
Catheter ablation is first-line treatment for symptomatic patients and is nearly always curative.
•
Flecainide or propafenone may be used prophylactically to slow accessory pathway conduction and prolong its refractory period.
•
Long-term drug therapy is not preferred for most patients. Amiodarone should not be used because of its side-effect profile; ablation is safer and more effective.
•
Digoxin and verapamil shorten the accessory pathway refractory period and should not be used.