Merck Manual

Please confirm that you are a health care professional

honeypot link

Atrial Fibrillation and Wolff-Parkinson-White Syndrome (WPW)

By

L. Brent Mitchell

, MD, Libin Cardiovascular Institute of Alberta, University of Calgary

Last full review/revision Jan 2021| Content last modified Jan 2021
Click here for Patient Education
Topic Resources

In Wolff-Parkinson-White syndrome, antegrade conduction occurs over an accessory pathway. If atrial fibrillation, develops this is a medical emergency as very rapid ventricular rates can develop.

In manifest Wolff-Parkinson-White (WPW) syndrome, antegrade conduction occurs over the accessory pathway. If atrial fibrillation develops, the normal rate-limiting effects of the atrioventricular (AV) node are bypassed, and the resultant excessive ventricular rates (sometimes 200 to 300 beats/minutes) may lead to ventricular fibrillation (see figure Atrial fibrillation in Wolff-Parkinson-White syndrome) and sudden death. Patients with concealed WPW syndrome are not at risk because in them, antegrade conduction does not occur over the accessory connection.

Atrial fibrillation in Wolff-Parkinson-White syndrome

Ventricular response is very fast (RR intervals minimum of 160 msec). Shortly thereafter, ventricular fibrillation develops (lead II continuous rhythm strip at bottom).

Atrial fibrillation in Wolff-Parkinson-White syndrome

Treatment of Atrial Fibrillation and WPW Syndrome

  • Direct-current cardioversion

The treatment of choice for Wolff-Parkinson-White syndrome is direct-current cardioversion. The usual rate-slowing drugs used in atrial fibrillation are not effective, and digoxin and the nondihydropyridine calcium channel blockers (eg, verapamil, diltiazem) are contraindicated because they may increase the ventricular rate and cause ventricular fibrillation. If cardioversion is impossible, drugs that prolong the refractory period of the accessory connection should be used. IV procainamide or amiodarone is preferred, but any class Ia, class Ic, or class III antiarrhythmic drug can be used.

Pearls & Pitfalls

  • Do not give digoxin or nondihydropyridine calcium channel blockers (eg, verapamil, diltiazem) to patients with atrial fibrillation and Wolff-Parkinson-White syndrome because these drugs may trigger ventricular fibrillation.

Click here for Patient Education
NOTE: This is the Professional Version. CONSUMERS: Click here for the Consumer Version
Professionals also read

Also of Interest

Download the Manuals App iOS ANDROID
Download the Manuals App iOS ANDROID
Download the Manuals App iOS ANDROID
TOP