The new concept of systolic myocardial stiffness was applied to the study of ejection mechanics in aortic valve disease. Frame-by-frame analysis of stress (a) and volume (V) was performed for two differently loaded beats in 26 patients who underwent simultaneous cineangiography and micromanometry: nine normal subjects, eight with isolated aortic regurgitation (AR), and nine with aortic stenosis (AS). Maximum myocardial stiffness (maxEaJ) was defined as the slope of the endsystolic (es) stress-strain relationship. End-systole was defined as the frame where stiffness was maximal, and strain was defined as E = loge (Dm/Dom)