Wolff-Parkinson-White syndrome (WPW) is a pre-excitation syndrome caused by the presence of at least one abnormal accessory electrical conduction pathway (bundle of Kent)) between the atria and the ventricles.
In sinus rhythm the electrocardiogram shows a short PR interval of less than 120 milliseconds, with a delta wave (slurred upstroke in the QRS complex which characteristically widens the QRS complex to more than 120milliseconds.
Patients can exhibit atrial fibrillation or ventricular arrhythmias. Treatment of these is usually by electrical cardioversion or amiodarone, although some other drugs are safe. Importantly adenosine, and drugs that slow A-V conduction such as verapamil, diltiazem and beta blockers can be dangerous.
There is an increased risk of sudden cardiac death but in practice risk stratification should be applied. For example the disappearance of delta waves as the heart rate increases (say with exercise) indicates lower risk. Best stratification requires full electrophysiological studies as well as patient history and sometimes genetics.
- Radiofrequency catheter ablation.
This article is a work in progress. Please feel free to contribute to it.