Heart: Wolff-Parkinson-White (WPW) Syndrome
Wolff-Parkinson-White (WPW) syndrome occurs in people who have a second, accessory pathway that conducts electrical signals between the atria and ventricles. WPW is usually hereditary or associated with congenital (present at birth) or acquired heart defects. In WPW, electrical signals bypass the AV node and use the extra pathway. They reach the ventricles too soon and bounce back to the atria. The signals ricochet around the inside of the heart, causing very fast heartbeats.
Although most people with WPW do not have symptoms, in some it can pose a serious risk for sudden death.