Predominant atrial remodeling in elite endurance athletes. a rare and un-investigated type of athlete's heart?

Although athlete’s heart is typically characterized by balanced enlargement of all cardiac chambers, previous investigations have placed relatively little focus on specific characteristics of atrial remodeling. The aim of our study is to describe cardiac remodeling in a cohort of elite endurance athletes, with a specific focus on atrial remodeling. Endurance athletes with unremarkable cardiovascular pre-participation screening test results underwent thorough multidisciplinary cardiovascular evaluation, which included transthoracic echocardiography. Atrial remodeling was defined as LAVi > 34 mL/m2, and ventricular eccentric remodeling as LVMi > 115 g/m2 in male or > 95 g/m2 in female and RWT ≤0.42. 396 athletes were enrolled (mean age 26.4±5.1 years, 58.1% males). According to cardiac remodeling, athletes were classified into four groups: those with both left atrio-ventricular (A-V) remodeling (12.9%), athletes with isolated LV remodeling (43.9%), athletes with predominant LA remodeling (4%) and subjects with no cardiac remodeling (39.1%). Mean LAVi of athletes with NO A-V remodeling, ventricular remodeling, atrial remodeling, and A-V remodeling were respectively: 22.7±5.2 ml/m2, 24.1±5 ml/m2, 39.2±4.2 ml/m2, and 39.2±4.3 ml/m2 (p < 0.0001). No differences in atrial functional parameters were found among the four group (LA expansion index, p = 0.0645 and LA strain parameters p > 0.1). No significant differences were found in diastolic and systolic LV function (E/E’, p = 0.191; E/A, p = 0.131; EF%, p = 0.517; LV GLS, p = 0.186) and in SVEB (p = 0.790). In elite endurance athletes a spectrum of cardiac remodeling is broader than usually described, ranging from the absence of evident structural changes to classic remodeling, with some cases exhibiting predominant atrial remodeling. This pattern was not associated with impaired atrial or ventricular function, nor with an increased incidence of atrial arrhythmias. Therefore, it could be considered a non-classical variant of the athlete’s heart.