Twenty one patients with acute inferior myocardial infarction underwent hemodynamic monitoring and coronary angiography study. 16 cases were diagnosed as having right ventricular myocardial infarction (RVMI) by the hemodynamic characteristics of RVMI and 5 cases no RVMI. In the 16 patients with RVMI, 15 (93.8%) had proximal or middle segment occlusion of right coronary artery (RCA) and the remaining one (6.3%) was caused by occlusion of left circumflex with no distal segment occlusion of RCA. According to the ratio of MRAP/PCWP, we divided the hemodynamic abnormality into two subgroups: MRAP/PCWP > or = 0.8 was considered severe and MRAP/PCWP 0.65-< 0.8 mild. In the 16 patients with RVMI, 10 cases were severe and 6 cases mild. The site of coronary artery occlusion in the severe group were 4/10 (40%) at proximal segmet of RCA and 5/10 (50%) at middle segmet of RCA and the remaining one case the site of occlusion was in circumflex, while in the mild group, 3/6 (50%) of the cases had occlusion at the proximal segment of RCA and 3/6 (50%) at middle segment of RCA. The results of this study showed that inferior myocardial infarction caused by proximal or middle segment occlusion of RCA might be accompanied by RVMI, but there was no relationship between the degree of hemodynamic abnormality and the site of RCA occlusion.