Aim of the study was to examine the role of echocardiography to classify patients with heart failure. Fifty-seven subjects (32 dilated cardiomyopathy (DCM), 9 aortic regurgitation (AR), 16 hypertensives (HT)--4 in Class (CI) NYHA I, 24 II, 15 III, 14 IV--were studied by M-2D echo. Eighty-seven normals (N) were the control group; 11 were controlled after clinical improvement (3.4 +/- 3.8 months); 11 after worsening (12 +/- 17). We have evaluated: left ventricular diastolic dimension (LVIDd), wall thickness/radius ratio (H/R), diastolic (D) and systolic volume (S Vol), ejection fraction (EF), systolic arterial pressure/end-systolic volume ratio (P/V), and stress. LVIDd and stress were increased in all groups; H/R reduced, except in HT and in Cl I; EF and P/V reduced except in Cl I. Between I and II LVIDd was different; between II and III all parameters were different, between III and IV only EF and P/V. According to regression S-D Vol, EF-P/V and EF-stress we identify the reduction of EF and the related mechanisms, ie reduced contractility or increased afterload. Thus, according to P/V and stress, we classify the patients in 4 pathopysiologic classes: 1 and 2 with P/V within 2 SD N: 1 with stress within 2SD N, EF and H/R normal; 2 with stress greater than +2SD, H/R normal and EF reduced; 3 and 4 with P/C less than -2 SD N: 3 with normal, 4 with stress greater than +2 SD. In the 1 and 2, 1 out 14 is in III Cl NYHA, none in IV; in 3,6 out 8 are in II, in 4, 9 out 35 are in Cl less than III. In the follow-up, in 8 of the improved patients, EF and P/V were increased and stress reduced; in 3, EF was reduced. In 8 of the worsened, EF and P/V were reduced, LVIDd and stress increased; in 3 EF and LVIDd were increased, P/V reduced. This study demonstrates discordance between Cl NYHA and echo, and how classification of NYHA does not give information about the several components of heart failure. However LVID and EF are not sufficient. By a correlation of echo-parameters of contractility, afterload and pump performance, we may suggest a classification of heart failure in pathophysiologic classes.