[Effects of endurance training on left ventricular filling dynamics: a study using stress Doppler echocardiography]

To evaluate the impact of endurance training on left-ventricular (LV) filling dynamics Doppler mitral flow was derived in 23 amateur endurance-trained athletes (AT) aged 31 (24-39) years with a personal marathon record greater than or equal to 200 min, and in 20 ultra-endurance athletes (UEA) aged 38 (28-42) years with a personal marathon record less than 200 min during bicycle exercise in supine position. Twenty-two untrained healthy volunteers (UT) aged 27 (24-30) years served as control. In particular, atrial filling fraction (AFF) as the relative share of atrial contribution to LV filling was measured. At rest AFF was significantly higher in UT (29%) as compared to AT (25%) and UEA (25%). During exercise (150 watt) atrial fraction increased significantly more in UT (37%) as compared to AT (34%) and UEA (29%) (p less than 0.01). At this point of measurement UEA had significantly lower values for AFF than AT (p less than 0.001). Two min post exercise atrial filling fraction already reached baseline values in UEA (24%) and AT (26%), while it remained significantly elevated in UT as compared to baseline values (38%, p less than 0.001). Ten min post exercise atrial filling fraction showed still elevated values in UT (32%), but decreased under baseline values in UEA (23%). No differences in heart rate between the two athlete groups at all times of measurement were observed. Thus, while atrial filling fraction rose in all study groups during exercise, it returned earlier to baseline values in athletes than in untrained subjects. This indicates a better cardiac adaptation to physical stress and a better diastolic performance during exercise in endurance-trained athletes, being even more pronounced in ultra-endurance athletes.