Wolff-Parkinson-White Syndrome

Wolff-Parkinson-White Syndrome, or WPW, is a condition in which there is an extra electrical pathway in the heart. Normally, the electrical signals follow a certain path which helps the heart beat regularly without extra beats. In people with WPW syndrome, some of the heart’s electrical signals travel down an extra pathway which may cause supraventricular tachycardia (rapid heart rate). The extra pathway is present at birth and rarely fatal. Episodes of tachycardia aren't life threatening however, heart problems may occur including an Ebstein anomaly (rare heart defect in which parts of the tricuspid valve are displaced or abnormal) may occur. WPW syndrome can affect all ages but is most commonly diagnosed in children, teens, and young adults. Other than a few rare cases, WPW syndrome is not a hereditary condition There is an average of 3 people affected in a population of 2,000.
            People of all ages can experience symptoms however they most often appear in the late teens to early 20s. Common symptoms include a rapid and pounding heartbeat, dizziness, lightheadedness, SOB (shortness of breath), fainting, fatigue as well as anxiety. Episodes of tachycardia may begin suddenly and last moments or hours. Episodes can occur during exercise or during periods of rest. Symptoms may be triggered by coffee, alcohol, as well as other stimulants. Over time, symptoms may disappear in as many as 25% of the people. In most serious cases, 10-30% of people with WPW syndrome have atrial fibrillation which is an irregular heartbeat. In these people, symptoms may include: chest pain, chest tightness, difficulty breathing, as well as fainting. Symptoms in infants may include an ashen color, restlessness, rapid breathing, as well as poor eating.
For most people, WPW syndrome does not cause significant problems however, complications may occur. If the disorder is untreated and there are other heart problems, patients are at risk of fainting, tachycardia, and rarely, sudden death.
            In order to diagnose this syndrome, doctors will usually perform many heart tests. In an EKG/ECG (electrocardiogram), small sensors are attached to the arms and legs to record electrical signals traveling through the heart. The recorded data will then be evaluated by a health professional in order to determine if there is an extra electrical pathway. A portable ECG can be work to provide information about the heart rate. A Holter monitor record heart activity for 24 hours while an event recorder monitors heart activity during tachycardia. Electrophysiological testing involves thin catheters with electrodes on the ends being threaded through blood vessels to various spots in the heart. These electrodes map electrical impulses throughout the heart and indicate if there is an extra electrical pathway.
            Doctors may prescribe a variety of treatments based on severity and frequency of symptoms. Those who do not have symptoms may not require treatment. However, if treatment is needed, the goal is to lower the rapid heart rate and prevent future episodes of tachycardia. Treatments include vagal maneuvers which are simple physical movements including coughing, bending forward and putting an icepack on the vagus nerve of the face to lower the rapid heart rate. If vagal movements don't work, doctors may deem an injection of an antiarrhythmic medication necessary. Cardioversion may also be used where doctors electrically shock the heart to restore a normal rhythm. This is typically only used when vagal maneuvers and medications are not effective.
Figure 1: Image showing the normal electrical pathways of a heart in comparison to the electrical pathways in a heart affected with WPW syndrome. In the heart with WPW syndrome, there is an irregular electrical pathway as well as tachycardia and other abnormalities in the EKG when compared to a normal sinus rhythm.