Pediatric Preexcitation Syndrome

Pre-excitation syndrome in children is an additional conduction beam between the atria and ventricles, also known as Wolff-Parkinson-White syndrome, with a pediatric incidence rate of 1/1000. Pre-excitation is a rare type of arrhythmia, and diagnosis is mainly based on electrocardiograms. There are residual non-specific myocardial fibrous muscle bundles across the atrioventricular valve annulus, which connect to the atrial ventricular muscles, called the atrioventricular bypass, which excites some ventricles in advance. This abnormal atrioventricular bypass has atrioventricular conduction, leading to abnormal electrophysiological manifestations and tachyarrhythmias. This remaining conduction bypass is caused by abnormal heart development. In the early stages of embryonic development, the atria and ventricles are a continuous structure. Later, the atrioventricular muscle connection gradually degenerates and disappears, replaced by fibrous rings. The formation of the right bypass is because the fetus does not form an atrioventricular fibrous ring during development, and is still connected by muscle fiber bundles. Most of these muscle structures disappear within the first 6 months of life. If the muscle bundle does not disappear after 6 months, or the atrioventricular fibrous ring is not formed, a bypass is formed. The formation of the left free wall bypass is mainly caused by the undegraded intermuscular connection during embryonic development.