Atrial Enlargement in the Athlete's Heart: Assessment of Atrial Function May Help Distinguish Adaptive from Pathologic Remodeling

Intensive training is associated with hemodynamic changes that typically induce an enlargement of cardiac chambers, involving not only the ventricles but also the atria. The hearts of competitive athletes are characterized by increases in left and right atrial dimensions that have been interpreted as a physiologic adaptation to training. Conversely, some authors have hypothesized maladaptive remodeling; furthermore, the extent of left atrial dimensional remodeling may overlap atrial dilation observed in patients with cardiac disease, representing a challenge for clinicians. However, studies investigating left and right atrial function in athletes have demonstrated that atrial size is insufficient to provide mechanistic information about the atrium itself, and an increase in atrial size is not intrinsically an expression of atrial dysfunction. The authors critically analyze training-induced atrial remodeling, taking into account not only the assessment of atrial size but also the evaluation of atrial function, suggesting that the characterization of atrial function plays a fundamental role in the evaluation of athlete's heart, being useful to differentiate physiologic remodeling induced by exercise from pathologic changes occurring in cardiac disorders.