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The aim of this study was to evaluate left atrial (LA) volume and its changes with the phases of atrial filling, and to examine the effect of exercise capacity on these parameters. Using two-dimensional echocardiography, LA volumes were measured in 30 male endurance runners and 30 age-matched sedentary men (controls). Maximal oxygen consumption (VO2max) was measured using a metabolic chart during exercise. LA reservoir, pump, and conduit functions, kinetic energy and force were calculated. We found that athletes had higher LA volume and volume index (except the conduit volume), LA passive emptying fraction, and LA total emptying fraction compared to control subjects. We observed positive correlations between: VO2max and LA passive emptying fraction (r=0.49, p<0.05); VO2max and LA active emptying fraction (r=0.54, p<0.05); VO2max and LA kinetic energy (r=0.61, p<0.05); and VO2max and LA force (r=0.57, p<0.05). These findings suggest that atrial function reflects exercise capacity in athletes.

Aortic elastic properties are important determinants of left ventricular function. The aim of this study was to determine left ventricular diastolic function and aortic distensibility in endurance athletes. Thirty male runners and thirty age-matched healthy male controls took part in the study. All subjects underwent echocardiographic examination and cardiopulmonary exercise testing. Measurements included LV cavity dimension, standard and tissue Doppler parameters, and aortic diameter, 3 cm above aortic valve, at systole and diastole. Maximal oxygen uptake in athletes was higher than in controls. The aortic distensibility index was found to be higher in athletes compared with controls (5.37 +/- 1.50 vs. 3.37 +/- 1.48 cm (2) . dynes (-1) . 10 (-6), p < 0.001). While the aortic stiffness index in athletes was significantly lower than in controls (2.77 +/- 0.28 vs. 3.43 +/- 0.41, p < 0.001). Furthermore, transmitral early peak velocity (E) and late peak velocity (A), peak velocity of myocardial systolic wave (S (m)), early (E (m)) and atrial (A (m)) diastolic waves in athletes were higher than in controls. It seemed that the association of E (m) velocity with aortic distensibility was stronger than that of other LV parameters (coefficient = 0.74, p < 0.001) by using multiple linear regression. Increased aortic distensibility in endurance-trained athletes may cause better diastolic function as a physiological cardiovascular adaptation factor.

Screening for cardiac health should involve relevant parameters or indices that are easy and inexpensive to obtain. Various cardiac adaptation mechanisms develop during regular exercise that are affected by many factors, and these are reflected on a surface electrocardiogram. QT dispersion has been considered a surrogate for heterogeneity of repolarization, leading to ventricular arrhythmias. We compared QT parameters between athletes and sedentary subjects. A total of 225 men were assessed, comprising a group of professional soccer players and sedentaries. Each subject underwent supine 12-lead electrocardiographic examinations and exercise testing by ergospirometry. QT parameters were taken at rest and at peak exercise. Peak oxygen consumption was considerably higher in the athletes than in the controls (59.3 +/- 5.6 vs. 44.3 +/- 2.4 ml/kg/min, mean +/- SD, p < 0.001). QT parameters at rest: There were significant differences in heart-rate-corrected rest maximal QT duration (413.9 +/- 50.5 vs. 445.3 +/- 45.7 ms, p < 0.001) and in heart-rate-corrected rest minimum QT duration (380.5 +/- 51.2 vs. 409.5 +/- 46.7 ms, p < 0.001). QT parameters at peak exercise: maximal QT duration at peak exercise (253.9 +/- 20.8 vs. 261.7 +/- 26.2, p = 0.02), QT dispersion at peak exercise (25.2 +/- 9.1 vs. 29.5 +/- 15.8 ms, p = 0.04), heart-rate-corrected QT dispersion at peak exercise (44.6 +/- 16.4 vs. 52.6 +/- 28.3 ms, p = 0.03) differed significantly between professional soccer players and controls. QT dispersion and corrected QT dispersion at peak exercise are lower in athletes than in controls. Athletes and other subjects identified with a long QT interval should be examined at regular intervals.