This article is the report of an International Symposium endorsed by the European Society of Cardiology, held within the Venice Arrhythmias 2007: 10 International Workshop on Cardiac Arrhythmias (Venice, October 2007). The topics of the Symposium are the following: how to stratify the risk of sudden death in athletes; the role of different diagnostic examinations in the risk stratification of sudden death in athletes; controversies on arrhythmias and sport; and exercise prescription in patients with arrhythmias.