The prediction and prevention of sudden cardiac death is the philosopher’s stone of clinical cardiac electrophysiology. Sports can act as triggers of fatal arrhythmias and therefore it is essential to promptly frame the athlete at risk and to carefully evaluate the suitability for both competitive and recreational sports activity. A history of syncope or palpitations, the presence of premature ventricular complexes or more complex arrhythmias, a reduced left ventricular systolic function, or the presence of known or familiar heart disease should prompt a thorough evaluation with second level examinations. In this regard, cardiac magnetic resonance and electrophysiological study play important roles in the diagnostic work-up. The role of genetics is increasing both in cardiomyopathies and in channelopathies, and a careful evaluation must be focused on genotype positive/phenotype negative subjects. In addition to being a trigger for fatal arrhythmias in certain cardiomyopathies, sports also play a role in the progression of the disease itself, especially in the case arrhythmogenic right ventricular cardiomyopathy. In this paper, we review the latest European guidelines on sport cardiology in patients with cardiovascular diseases, focusing on arrhythmic risk stratification and the management of cardiomyopathies and channelopathies.