Effect of changes in left ventricular diastolic function during exercise on exercise tolerance assessed by...

Cardiac function during exercise is assumed to be important in determining exercise tolerance. The aims of this study were to evaluate changes in left ventricular diastolic function (LVDF) during exercise and its effect on exercise tolerance assessed by a noninvasive method, exercise-stress tissue Doppler echocardiography. Twenty-six men with sinus rhythm (controls, hypertension, and cardiomyopathy) underwent cardiopulmonary exercise testing. To assess LVDF during exercise, exercise-stress Doppler echocardiography was performed with a constant workload at rest, and at 50%, 100%, and 120% of anaerobic threshold (AT). Doppler variables related to LVDF increased significantly as the workload increased (P < 0.05). Resting E'correlated significantly with AT (r = 0.424, P = 0.0308) and peak VO(2) (r = 0.471, P = 0.0152). However, the difference in E'between rest and 120% AT (DeltaE') was closely correlated with AT (r = 0.744, P < 0.0001) and peak VO(2) (r = 0.748, P < 0.0001). Moreover, DeltaE'was correlated independently with AT (P = 0.0321) and peak VO(2) (P = 0.0192) by multiple regression analysis. These results suggest that the ability to increase LVDF during exercise is an important factor in determining exercise tolerance.