Comprehensive 2 D/Doppler examination of 98 patients (mean age 56), implanted between September 1984 and February 1991, with normally functioning aortic (n = 49) and mitral (n = 49) Omnicarbon valves (OC) were analyzed in order to characterize the normal hemodynamic profiles of the OC valves. The mean time from implantation was 36.4 months (range 6 to 78). The following parameters were assessed (average of 5 measurements): peak transvalvular velocity (peak V), peak instantaneous gradient (peak G), mean transvalvular gradient (mean G), effective aortic valve area (ef Va), modified aortic valve area (m Va), aortic permeability index (PI), mitral valve area (Mit Va). Doppler data were correlated to prosthetic sizes (ranging from 21-29 mm for aortic OC and from 23-31 mm for mitral OC). The study establishes normal Doppler hemodynamics for each size (especially in aortic position) of OC valves and shows excellent performance. Significant correlations between peak G, mean G, Pl, and prosthetic aortic valve size (AS) were moderate. By contrast there were strong relationships between AS and ef Va (r = 0.56, p < 0.001) or mVa (r = 0.55, p < 0.001). These data should be helpful to identify OC prosthetic dysfunction.