Wolff-Parkinson-White syndrome is a special type of supraventricular arrhythmias. It's a condition in which the heart's electrical signals travel along an extra pathway between the atria and the ventricles. This pathway may allow electrical current to pass between the atria and the ventricles without passing through the atrioventricular node which disrupts the timing of the heart's electrical signals and can cause the ventricles to beat very fast which can be life threatening.
Attribution: Straight Talk Foundation