Sudden death in the young is rare. About 25% of cases occur during sports. Most 
young people with sudden cardiac death (SCD) have underlying heart disease, with 
hypertrophic cardiomyopathy and coronary artery anomalies being commonest in 
most series. Arrhythmogenic right ventricular dysplasia and long QT syndrome are 
the most common primary arrhythmic causes of SCD. It is estimated that early 
cardiopulmonary resuscitation and widespread availability of automatic external 
defibrillators could prevent about a quarter of pediatric sudden deaths.