To assess left ventricular (LV) diastolic function in patients with LV dysfunction, LV pressures (manometer tip) and biplane angiograms were analyzed for 27 patients with LV systolic dysfunction (EF < or = 0.45) (dilated cardiomyopathy or coronary artery disease) and 18 normal controls. LV volumes were obtained from frame-by-frame analyses of angiograms. LV relaxation was assessed by the time constant (T) of LV pressure decay. LV relaxation was impaired in patients with LV dysfunction, however, early diastolic filling assessed by the peak filling rate (PFR) and mean filling rate (MFR) during the rapid filling phase was maintained. Compared to the control group, early diastolic filling was significantly decreased in patients with LV dysfunction without mitral regurgitation (MR), but not in those with LV dysfunction with MR. In conclusion, although diastolic filling may be modified by MR, LV relaxation and early diastolic filling are essentially impaired in patients with LV dysfunction.