Abstract 714: Left Atrial Enlargement in 515 Either Endurance or Strength Competitive Athletes
Background. Increase of left atrial (LA) diameter in trained athletes has been regarded as another component of the “athlete’s heart. However, the prevalence of LA volume enlargement in competitive athletes is still unresolved.
Aim of the study. To evaluate the possible impact of competitive training on LA volume and to define reference values of LA volume index in athletes.
Methods. The study population included 320 endurance-trained athletes (ATE) and 195 strength-trained athletes (ATS) (380 males; mean age 24.3 ±15.6 years; range: 18–40). Left atrial maximal volume was measured at the point of mitral valve opening using the biplane area-length method, and corrected for body surface area. LA mild dilatation was defined as a LA volume index ≥ than 29 ml/m2, while a moderate dilatation was identified by a LA volume index ≥ than 34 ml/m2.
Results. Left ventricular (LV) mass index and ejection fraction did not significantly differ between the 2 groups. However, ATS showed increased sum of wall thickness, LV circumferential end-systolic stress (ESSc) and relative wall thickness, while LV stroke volume and LV end-diastolic diameter were greater in ATE. The range of LA volume index was 25 to 36 ml/m2 (mean: 27.5±9.2) in men and 23 to 33 ml/m2 (mean: 26.5±7.2) in women. LA volume index was mildly enlarged in 101 athletes (19.5 %), and moderately enlarged only in 14 (2.6%). Mild mitral regurgitation was observed in 47 athletes (9.5 %). LA volume index was significantly greater in ATE. By multiple linear regression analyses, in the overall population of athletes duration of training (p<0.001) and left ventricular diameter (p<0.001) were the only independent predictors of LA volume index.
Conclusions. In a large population of highly trained athletes, a mild enlargement of LA volume was relatively common and may be regarded as a physiologic adaptation to exercise conditioning, with the upper limits of 33 ml/m2 in women and 36 ml/m2 in men distinguishing physiologic cardiac remodelling.