Background: E/Em is a well known echocardiographic parameter of increased left ventricular filling pressure and associated with cardiac hemodynamic burdens and prognosis in various clinical settings. NT-proBNP is also a well known biomarker of hemodynamic burdens and prognosis in various cardiac diseases including heart failure and acute myocardial infarction (AMI). Because the wall motion of basal inferior septum is frequently abnormal in patients with AMI of right coronary artery (RCA), it is expected that septal Em on tissue Doppler imaging might be more affected in RCA territory AMI than in non-RCA territory AMI. The aim of the present study was to investigate the impact of infarct related artery on the hemodynamic burdens as measured by E/Em in patients with AMI as compared with NT-proBNP. Methods: A total of 881 patients with AMI were divided into 2 groups; the patients with AMI of RCA territory (group I, n=257, 177 males, 59.7짹13.6 years) versus the patients with non-RCA territory AMI (group II, n=624, 415 males, 60.2짹15.1 years). The correlation between E/Em and NT-proBNP was compared between the groups. Results: E/Em (13.4짹10.8 in group I vs 12.5짹6.1 in group II, p=0.180) and the level of NT-proBNP (2954.0짹5777.5 pg/mL in group I vs 3567.1짹7283.2 pg/mL in group II, p=0.127) were not different between the groups. Overall, E/Em showed significant correlation with NT-proBNP (r=0.24, p<0.01). E/Em, however, did not show significant correlation with NT-proBNP in group I (r=0.087, p=ns). E/Em showed better significant correlation with NT-proBNP in group II (r=0.412, p<0.01). Conclusion: E/Em showed significant correlation with NT-proBNP in patients with AMI. However, E/Em could not reflect hemodynamic burdens as measured by NT-proBNP in patients with RCA territory AMI. Therefore, the significance of E/Em should be interpreted cautiously in AMI patients with RCA territory.