The objective of the study was to assess the effect of preload alternations on a nongeometric Doppler index of combined systolic and diastolic myocardial performance (MPI). Doppler echocardiography was performed during Valsalva maneuver, passive leg lifting, and after sublingual administration of nitroglycerin in 50 healthy volunteers (group 1) and 25 patients (group 2) with previous myocardial infarction. MPI was significantly lower in group 1 (0.34 +/- 0.04) compared with group 2 (0.52 +/- 0.14), P <.0005. In group 1 MPI was significantly increased during preload manipulations (P =. 001). The largest change in MPI was induced by nitroglycerin (0.034 +/- 0.05). In group 2 no significant changes in MPI were found. In both groups peak E-wave velocity (P <.0005), E/A-ratio (P <.0005), and E-wave deceleration time (P <.0005) were found to change during preload alternations. In conclusion, we found in normal subjects and to a lesser extent in patients with previous myocardial infarction that MPI is influenced by preload.