Objective: The aim of this study is to compare the impact of two different loading conditions on myocardial contractility in asymptomatic patients with normal EF by using stain rate imaging (SRI). Methods: A total of 27 patients with severe aortic regurgitation (mean age 50 +/- 11 years) and 25 patients with severe aortic stenosis (mean age 53 +/- 15 years) were prospectively recruited. Fifteen healthy subjects (mean age 50 +/- 6 years) were enrolled as the control group. For the evaluation myocardial contractility, longitudinal LV function was chosen and, midventricular segment shortening was analyzed for the septum, LV lateral wall from apical four-chamber view and for the anterior, inferior wall from apical two-chamber view. Results: Longitudinal peak systolic strain rate values of each segment derived from analysis of a total of 804 segments were significantly decreased in the patients population (P < 0.001). Global longitudinal peak systolic strain rate was also significantly decreased in aortic stenosis and regurgitation compared to the control group (-1 +/- 0.5, -0.9 +/- 0.3, and -1.6 +/- 0.3, P = 0.001). As far as the comparison between patients with aortic stenosis and aortic regurgitation, neither global strain rate nor strain rate for each wall was found to be different. Conclusion: We conclude that longitudinal LV function is reduced in both pressure and volume overload, and both of this overload patterns are equally harmful to the ventricle. (Echocardiography 2010;27:798-802).