In order to evaluate the effect of handgrip on left ventricular dynamics, cineventriculography was performed in 16 patients with heart disease and 5 normal subjects at 30% of maximal voluntary contraction. No patient had ventriculographic evidence of asynergy or valve regurgitation. During exercise, left-ventricular end-diastolic volume (LVEDV) insignificantly increased, left ventricular end-systolic volume (LVESV) decreased, and hence stroke volume (SV) and ejection fraction (EF) rose in the normal group, while in the patient group a similar change in LVEDV was associated with increased LVESV, resulting in unchanged SV and decreased EF. It is notable that during exercise LVEDV increased in both groups, despite a shortened diastolic filling period. Mean velocity of fiber shortening (mean VCF) increased in the normal group and remained unchanged in the patient group. The changes in mean VCF during exercise were correlated with the alterations in SV and EF (r=0.46, p less than 0.05 and r=0.90, p less than 0.001), respectively). These data signify that an increased afterload induced by handgrip leads to an enhanced left ventricular myocardial contraction in addition to an increase in preload in the normal group, while the Frank-Starling mechanism is mainly utilized in the patient group.