[The "athlete's heart": structure, function and differential diagnosis].

Long-term, intense sport activity induces morphologic and functional adaptations on cardiovascular system. The magnitude of these changes is determined by various factors, creating a specific condition: the "Athlete's Heart" (AH). It is important to distinguish this entity from other cardiomyopathies, taking into account that the differential diagnosis can be challenging. There has been an increase in the number of people practicing sports, which goes in parallel with the increase in the prevalence of AH. However, the proportion of asymptomatic subjects affected by cardiovascular diseases taking part on competitive sports, is also growing. We revise the main characteristics of AH, as well as the key points to distinguish AH from pathologic conditions. A delicate characterization as AH or cardiomyopathy would help to settle appropriate measures to lower the risk of sports-related sudden cardiac death.