Wolff-Parkinson-White Syndrome (WPW Syndrome) is a cardiac abnormality caused by abnormal electric pathways in the heart. Normally, electric conduction in the heart travels from the atria to the ventricles through the AV node. However, in WPW Syndrome, an extra abnormal electric pathway, called the Bundle of Kent, appears. This abnormal pathway is unregulated, causing arrhythmia, pre-excitation, and sometimes tachycardia. Supra-ventricular tachycardia may also result, when the electrical activity re-enters the atria through this pathway. Individuals affected with this syndrome may remain asymptomatic, with only their ECG pattern showing an abnormality. On the other hand, other patients may show symptoms ranging from tachycardia, dizziness, light-headedness, palpitations, or fainting, to even heart failure. The condition is one of the most frequent causes of rapid heart beat in young children. About 1 to 3 people in every 1,000 are affected with this condition; about 60-70% of who are males.
WPW Syndrome can be easily diagnosed on the basis of its characteristically abnormal ECG pattern, with a short PR interval and a slurred QRS complex. Individuals, who show no symptoms, need not take the help of medications. Others however need to be put on antiarrhythmics, and other drugs, such as adenosine. Ablation of the Bundle of Kent tissue is a permanent mode of treatment. This ablation may be either through open-heart surgery, or via radio frequency catheter ablation.
Mutations in the PRKAG2 gene have been identified in a few reported cases of WPW Syndrome. This gene codes for one of the regulatory subunits of the AMP-activated protein kinase complex, an enzyme involved in the sensing of and response to energy demands within cells. Mutations in the PRKAG2 gene may result in WPW Syndrome by allowing the build up of glycogen inside cardiac muscle cells, or by dysregulating certain cardiac ion channels.