Normally, electricity runs from the top of the atium (upper heart chamber) through the middle- or septum, of the heart and then through the ventricles (lower heart chamber) causing the heart muscle to contract in a coordinated manner. WPW occurs when an extra electrical connection (an accesory pathway) exists between the atria and ventricles of the heart. This leads to an abnormal heart rhythm (an arrhythmia) which is usually felt by the patient as palpatations and a very rapid heart rate. The most common arrhythmia in WPW is called supraventricular tachycardia (SVT).

image of WPW pathway taken from epmcg.net

Who gets WPW?

WPW is present in appoximately 3 per 2000 people. Less than 1% of people with WPW have a family history of it. The vast majority of people with WPW never know they have it since it is completely silent most of the time with no symptoms expressed. These people will only know they have it when a routine EKG (or electrical heart tracing) is done.

What symptoms should I watch out for?

As explained above, only a small minority of those with WPW will actually express the classic symptoms. These symptoms are palpatations and a racing heart rate over 150 beats per minute. Occasionally, these symptoms will be followed by loss of consicousness due to a brief lack of blood flow to the brain. When the patient has no symptoms there is nothing to find on examination.

How is WPW diagnosed?

The primary test is an EKG. There are two findings on the EKG which are diagnostic of WPW. These are a short PR interval (short conduction from the artia to the ventricle) and a delta "slur" wave (which represents early activation of the ventricles from the accessory pathway.) As mentioned above, WPW is often an incidental finding found on a routine EKG done as part of a general physical.

What is the treatment for WPW?

If the brief episodes of SVT and palpatations become a nuisance, the abnormal rhythm can be controlled with medicines. However, the ideal treatment in patients with symptoms is to simply destroy the extra electrical pathway, a procedure called radio frequency ablation. During this procedure a wire is threaded from the femoral artery in the groin up to the right side of the heart. The extra electrical pathway is then located and destroyed using a high current. The procedure takes about 2 hours and an overnight stay in the hospital is required to ensure normal electrical conduction remains in the heart. The only risks of the procedure are bleeding at the groin, infection, and damage to the structures of the right heart. However the overall rate of complications is low at 1 in 500. The procedure has well over a 90% success rate.

If I have palpatations and a racing heart, do I have WPW?

Only your doctor can determine if you have WPW. However other conditions can lead to palpatations, some of which are benign and others which are more serious. These include other types of arrhythmias, heart attack, inflammation of the heart, and infection of a heart valve. Therefore, if you have these symtoms for the first time tell you doctor.