Cardiovascular diseases account for 40% of all deaths in the Western countries, 
and nearly two thirds of them occur suddenly. Young people (<35 years) are not 
spared from sudden death (SD) with a rate of 1/100,000 per year. Effort is a 
trigger with a threefold risk in athletes vs. nonathletes, and sports 
disqualification is by itself life-saving in people with underlying concealed 
cardiovascular diseases. Several culprits of cardiac SD may be identified at 
postmortem and atherosclerotic coronary artery disease is the leading cause (25% 
of SD cases in the young), mostly consisting of a single obstructive plaque with 
fibrocellular intimal proliferation. However, the spectrum of cardiovascular 
substrates is wide and include also congenital diseases of the coronary arteries 
(mainly anomalous origin), myocardium (arrhythmogenic and hypertrophic 
cardiomyopathies, myocarditis), valves (aortic stenosis and mitral valve 
prolapse), and conduction system (ventricular preexcitation, accelerated 
atrioventricular conduction and block). In up to 20% of cases, the heart is 
grossly and histologically normal at autopsy (unexplained SD or "mors sine 
materia"), and inherited ion channel diseases have been implicated (long and 
short QT syndromes, Brugada syndrome, catecholaminergic polymorphic ventricular 
tachycardia). Targets to treat and prevent SD in the young consist of the 
following: (a) avoid triggers like effort or emotion, (b) inhibit the onset of 
arrhythmias with drugs or ablation, (c) switch off arrhythmias with 
defibrillator, and (d) hinder the recurrence of the disease with genetic 
counseling and/or therapy. In vivo detection of cardiomyopathies is nowadays 
feasible by electrocardiogram and/or echocardiography, which resulted in a sharp 
decline of SD in the athletes in Italy, thanks to obligatory preparticipation 
screening for sport activity. Genetic screening could play a pivotal role in 
early detection of asymptomatic mutation carriers of cardiovascular diseases at 
risk of SD.