The authors study retrospectively some preoperative echocardiographic findings and their importance as predictors of reversible myocardial dysfunction. The functional status of 57 survivors after isolated aortic valve replacement was evaluated with exercise testing and on this ground the patients, were divided into three groups: A (28 pts) greater than 60%; C (10 pts) less than 40%; B (19 pts) from 40% to 60%. The authors conclude that the postoperative improvement in functional status is strictly correlated with some preoperative echocardiographic indexes (end-diastolic dimension, end-systolic dimension, shortening fraction, mean end-systolic radius/thickness ratio, end-systolic wall stress, myocardial mass, ejection fraction) with are also predictive of operative mortality. The authors consider the principal values of beginning left ventricular impairment: a) end-systolic dimension greater than or equal to 5.5 cm; b) shortening fraction less than 27%; c) mean end-systolic radius/thickness ratio greater than 2.5; d) end-systolic wall stress greater than 240 mmHg.