Echocardiographic Doppler assessments of left ventricular filling and ejection during upright exercise in endurance...

Doppler echocardiography was used to describe left ventricular filling and ejection during upright bicycle exercise in 24 healthy male endurance athletes. The transmitral pressure gradient was estimated and isovolumetric relaxation, filling and ejection time and transmitral and aortic flow velocities were measured at rest and during exercise. From rest to peak exercise (at a heart rate of 160 bpm), the mean left ventricular filling time was shortened by 73%, the ejection time by 31%, while the isovolumetric relaxation time was shortened by 62%. At peak exercise, the maximum aortic flow velocity almost doubled and the maximum transmitral flow velocity more than doubled, with a tenfold increase in the mean transmitral pressure gradient. The increase was significant (P<0.001) at each level of exercise. The left ventricular filling rate measured as volume per time was 185 +/- 62 ml s(-1) at rest and it increased to 986 +/- 192 ml s(-1) at peak exercise. This study demonstrates large changes in diastolic filling indices during upright exercise and it shows that the heart is able to increase its filling rate five times from rest to peak exercise.