While there are a number of possible causes, there are three common causes. One cause is Hypertrophic Cardiomyopathy (HCM), a congenital heart muscle disease in which the walls of the hearts left ventricle become abnormally thickened. The structural abnormality can lead to obstruction of blood flow from the heart, causing loss of consciousness and an irregular heartbeat, leading to SCA. Another cause, Long QT syndrome, is an often-unrecognized congenital condition that predisposes the child to an abnormality in the hearts electrical system that can lead to SCA. Episodes are most commonly triggered by physical exertion or emotional stress. Finally, commotio cordis is an electrical disturbance caused by a blow to the chest. It occurs most often in baseball, but has been reported in other sports and situations in which there is a blow to the chest.
