Aim of our study was to assess if the 2D-Echo transverse diameter of the left hepatic vein (LHV) obtained from the subcostal approach is correlated with invasive mean right atrial pressure (RAP). Thirty-two consecutive patients with acute myocardial infarction were studied by simultaneous 2D-Echo and right heart catheterization. LHV could be adequately imaged in 90% of patients. Mean RAP values at catheterization ranged from 0 to 15 mmHg (mean 6 +/- 3.5 mmHg). A correlation was found between mean RAP and LHV diameter calculated after inspiration (r = 0.81, SEE = 1.54 mm, slope = 0.71, p less than 0.001) as well as after expiration (r = 0.82, SEE = 1.32 mm, slope = 0.62, p less than 0.001) or during post-expiratory apnoea (r = 0.85, SEE = 1.3 mm, slope = 0.71, p less than 0.001). Moreover, percent increments of LHV diameter correlated well with percent changes of mean RAP during rapid infusion of 250-500 cc of saline in 4 patients (r = 0.98, p less than 0.001). Thus, the 2D-Echo LHV diameter is a feasible measurement that seems to correlate well with invasive mean RAP over a wide range of mean RAP values in patients with myocardial infarction; the changes in LHV diameter correlate well with the percent increase in central venous pressure obtained with saline infusion. Underestimation of invasive RAP occurs when mean RAP value exceeds 12 mmHg and can be explained by limited venous compliance. However these preliminary results suggest that this method may represent a valid alternative to obtain a non invasive estimate of mean RAP with 2D-Echocardiography.