Normally, electrical signals in the heart go through the atrioventricular (AV) node, the pathway connecting the two top chambers of the heart (atria) to the two bottom chambers (ventricles). In people with Wolff-Parkinson-White syndrome, there is an extra, or accessory, AV pathway. This leads to "re-entry supraventricular tachycardia," a rapid heart rate initiated above the ventricles. The location of the extra electrical pathway in Wolff-Parkinson-White can often be precisely identified.Wolff-Parkinson-White occurs is one of the most common causes of fast heart rate disorders (tachyarrhymthmias) in infants and children. How often the rapid heart rate occurs depends on the patient. Some people with Wolff-Parkinson-White may have just a few episodes of rapid heart rate, others may experience the rapid heart rate once or twice a week. In some cases, the patient has no symptoms. In this case, the extra pathway is often found when a doctor has requested an ECG for some other purpose.
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