Thirty-five patients with previous myocardial infarction and 25 normal subjects underwent subcostal view two-dimensional echocardiography at rest and at peak up-right bicycle exercise. The purpose was to assess changes in left ventricular volume with maximal upright bicycle exercise and to compare the utility of the peak systolic pressure/end-systolic volume index ratio and ejection fraction as indicators of left ventricular function. With exercise, normal subjects had a decrease in end-systolic volume index (22 +/- 8 to 11 +/- 3 ml/m2) (p less than 0.001); the normal ejection fraction (59 +/- 9 to 72 +/- 8%, p less than 0.001) and the pressure/volume ratio (6 +/- 3 to 18 +/- 6, p less than 0.001) increased. In patients with prior myocardial infarction there was no change in end-systolic volume index, ejection fraction or pressure/volume ratio with exercise. Although at peak exercise significant differences between normal subjects and patients with prior infarction were demonstrated in end-systolic volume index (p less than 0.001), ejection fraction (p less than 0.001) and pressure/volume ratio (p less than 0.001), the pressure/volume ratio provided sharper delineation between the two groups than did ejection fraction. The exponential relation of the pressure/volume ratio and ejection fraction at peak exercise demonstrates that the pressure/volume ratio is more sensitive as an indicator of normal or borderline left ventricular function and that ejection fraction is more sensitive in quantifying the degree of left ventricular dysfunction.(ABSTRACT TRUNCATED AT 250 WORDS)