Assessment of left ventricular dimensions and functions in athletes and sedentary subjects at rest and during exercise using echocardiography, Doppler sonography and radionuclide ventriculography.

During recent years the echocardiographic procedure has been extended regarding the evaluation of left ventricular myocardial function during exertion. During exercise echocardiography, body position is important for the correct assessment of cardiac dimensions and function, particularly for the measurement of the cross-sectional diameters of the left ventricle and diastolic myocardial function. Reliable parameters of left ventricular function during exercise are left ventricular ejection fraction and endsystolic left ventricular volume, but not enddiastolic left ventricular volume. The increase of left ventricular ejection fraction during exercise up to submaximal exertion primarily results in a reduction of endsystolic left ventricular volume and partially in a simultaneous increase of enddiastolic left ventricular volume. In several cross-sectional studies comparing untrained and endurance trained hearts a higher diastolic filling rate, a higher maximal blood flow velocity of early diastolic passive left ventricular filling and a higher early diastolic filling fraction at rest and during exercise could be proved in endurance trained hearts. These training-induced adaptations of diastolic left ventricular function have been confirmed by a longitudinal study with primarily untrained young and older healthy subjects performing a heart rate controlled endurance training programme. Stress echocardiographic and simultaneous spiroergometric investigations indicated a correlation between the diastolic left ventricular function and the maximal oxygen uptake. The currently available data on the sensitivity, the intraobserver and interobserver variability of Doppler echocardiography have shown that this non-invasive procedure is valid for the evaluation of the systolic and the diastolic myocardial function at rest and during exercise. However, the procedure is limited to patients where the ultrasonographic assessment of cardiac structures is not considerably restricted. Furthermore, the reliability of stress Doppler echocardiography is dependent considerably on the practical skills of the observer.