RESUMO
Enlargement of the left atrium is perceived as a part of athlete's heart syndrome, despite the lack of evidence. So far, left atrial size has not been assessed in the context of exercise capacity. The hypothesis of the present study was that LA enlargement in athletes was physiological and fitness-related condition. In addition, we tried to assess the feasibility and normal values of left atrial strain parameters and their relationship with other signs of athlete's heart. The study group consisted of 114 international-level rowers (17.5 ± 1.5 years old; 46.5% women). All participants underwent a cardio-pulmonary exercise test and resting transthoracic echocardiography. Beside standard echocardiographic measurements, two dimensional speckle tracking echocardiography was used to assess average peak atrial longitudinal strain, peak atrial contraction strain and early left atrial diastolic longitudinal strain. Mild, moderate and severe left atrial enlargement was present in 27.2°%, 11.4% and 4.4% athletes, respectively. There were no significant differences between subgroups with different range of left atrial enlargement in any of echocardiographic parameters of the left ventricle diastolic function, filling pressure or hypertrophy. A significant correlation was found between the left atrial volume index and maximal aerobic capacity (R > 0.3; p < 0.001). Left atrial strain parameters were independent of atrial size, left ventricle hypertrophy and left ventricle filling pressure. Decreased peak atrial longitudinal strain was observed in 4 individuals (3.5%). We concluded that LA enlargement was common in healthy, young athletes participating in endurance sport disciplines with a high level of static exertion and was strictly correlated with exercise capacity, therefore, could be perceived as another sign of athlete's heart.
RESUMO
BACKGROUND: The prevalence and significance of the early repolarisation (ER) pattern in the general population has raised a number of questions. Even less data are available on athletes. AIM: To determine the prevalence and determinants of ER in a group of young high endurance athletes. METHODS: We studied 117 rowers (46% women, mean age 17.5 ± 1.5 years, mean training duration 4.3 ± 1.8 years). On 12-lead electrocardiogram (ECG), we evaluated inferolateral leads for the presence of the ER pattern, defined as at least 0.1 mV elevation of the QRS-ST junction (J point) from the baseline in at least two leads. All subjects underwent detailed echocardiographic study, cardiopulmonary exercise test with evaluation of VO2max (mean 57.1 ± 8.4 mL/kg/min), and evaluation of complete blood count and biometric parameters (fat tissue, body mass index, body surface area). RESULTS: We identified 35 subjects with ER in the inferior and/or lateral leads. The phenomenon was more frequent in males (n = 25, 21.36% of the overall study population) than in females (n = 10, 8.54%, p = 0.01). The training duration in both groups (with or without ER) was similar (4.4 ± 1.5 vs. 4.3 ± 1.8 years, p > 0.05). Athletes with the ER pattern had significantly higher VO2max (58.8 ± 7.8 vs. 55.3 ± 8.2 mL/kg/min, p = 0.03), lower resting heart rate (58.7 ± 11.3 vs. 65.4 ± 11.9 bpm, p < 0.01), higher haemoglobin level (15.2 ± 0.8 vs. 14.6 ± 1.2 g/dL, p < 0.01), higher red blood cell count (5.31 ± 0.3 vs. 4.98 ± 0.4 million/µL, p = 0.04), and lower fat tissue mass (12.1 ± 4.4 vs. 14.9 ± 6.0 kg, p < 0.01). Compared with the others, the ER group was characterised by a higher left atrial area index (12.2 ± 1.3 vs. 11.5 ± 1.6 cm²/m², p = 0.01), right atrial area index (9.9 ± 1.3 vs. 9.0 ± 1.4 cm²/m², p < 0.01), and right ventricular basal diameter index (2.0 ± 0.2 vs. 1.9 ± 0.2 cm/m², p = 0.04). We found no significant differences in any other cardiac size and function parameters. CONCLUSIONS: ER pattern in the inferior and/or lateral leads is a frequent finding in the population of young high endurance rowers. The presence of ER pattern is associated with gender and a number of parameters reflecting the general level of fitness and may be considered an electrophysiological sign of the athlete's heart. The significance of these alterations should be evaluated in prospective follow-up studies.
