Current Doppler methods have been unreliable in estimating filling pressures in heart transplants. Tissue Doppler imaging is a technique that permits evaluation of myocardial relaxation; combined with transvalvular E velocity, it could improve estimation of these pressures. To investigate this possibility, we evaluated 50 patients by right-sided cardiac catheterization and Doppler echocardiography simultaneously. Their mean +/-SD age was 53+/-15 years and the mean age of donor hearts was 30+/-12.5 years. The mitral E velocity was combined with the early myocardial relaxation (Ea) velocity by tissue Doppler at the lateral border of the mitral annulus. Likewise, the tricuspid E velocity was combined with Ea at the lateral corner of the tricuspid annulus. Mean wedge pressure related weakly to mitral inflow variables but strongly to E/Ea [r=0.8; wedge pressure=2.6+1.46(E/Ea)]. In 25 repeat right-sided cardiac catheterizations, changes in mean wedge pressure were well detected by Doppler, with a mean difference of -0.7+/-3 mm Hg. Mean right atrial pressure related weakly to routine tricuspid inflow variables but strongly to tricuspid E/Ea [r=0.79; n=38; right atrial pressure=1.76(E/Ea) - 3.7]. In 18 repeat right-sided cardiac catheterizations, changes in mean right atrial pressure were well detected by Doppler, with a mean difference of 0+/-3.45 mm Hg. Mean wedge pressure and mean right atrial pressure can be estimated in heart transplants with reasonable accuracy using the ratio of E/Ea. Furthermore, this method can accurately track changes in filling pressures.