To assess the left ventricular (LV) global and regional (anterior, apical, inferior) diastolic filling dynamics in compensated dilated cardiomyopathy (DCM), we measured left ventricular pressure and instantaneous volume from angiography in 7 normal controls (CTL) and 6 DCM patients with sinus rhythm. Global and regional peak filling rate (PER), time constant of LV pressure decline (T; Weiss's method) and LV chamber stiffness (k; Gaasch's method) were calculated. In DCM, left ventricular end-diastolic volume (ml/m2) was larger than in CTL (137 +/- 29 vs. 74 +/- 6, p less than 0.001), and stroke index (ml/m2) was not different from CTL (46 +/- 14 vs. 46 +/- 8, NS), indicating a compensated state of LV. Mitral valve opening pressure (mmHg) tended to increase in DCM compared with CTL (12 +/- 6 vs. 8 +/- 4). Global PFR (ml/sec/m2) (CTL = 216 +/- 47 vs. DCM = 201 +/- 36) and k (CTL = 0.044 +/- 0.023 vs. DCM = 0.029 +/- 0.016) were not different between 2 groups. However, T (msec) was markedly prolonged in DCM compared with CTL (61 +/- 10 vs. 35 +/- 5, p less than 0.001). In CTL, regional PFR (1/sec) showed almost the same values in each region, but in DCM, apical region showed higher PFR than in other regions. Thus, early diastolic filling might play an important role in maintaining the total transmitral flow in DCM despite severe impairment of LV relaxation. This compensation could be related mainly to accelerated regional lengthening of the LV apical region.