Children with SVT are born with an extra electrical pathway, most commonly separate from the normal conduction system. Some children have an extra electrical connection coming from the normal conduction system. Being born with an extra electrical connection cannot be caused or prevented during pregnancy. Sometimes evidence of an extra pathway can be seen on an electrocardiogram (ECG), which is test that shows an electrical tracing of the heart activity. Pathways that can be seen on an ECG are called Wolff-Parkison-White syndrome, though most children with SVT have normal ECGs. SVT does not commonly run in families, though is a common diagnosis so can be seen in multiple family members. Rarely, SVT occurs because the child has another heart issue at birth. A pediatric cardiologist will look for possible causes and any congenital heart defects. Most infants with SVT have an otherwise normal heart.