OBJECTIVES: N-terminal pro B-type natriuretic peptide (NT-proBNP) levels early after STEMI are known to be correlated with infarct size. During follow-up (FU), NT-proBNP levels are elevated in patients even in the absence of overt heart failure. We investigated correlation of the clinical and cardiac MRI predictor of NT-proBNP levels at 6 month follow-up in stable patients after STEMI treated with PCI. METHODS: 25 patients who had STEMI and underwent successful primary PCI in our institute were investigated. We performed dobutamine and adenosine stress gadolinium-enhanced cardiac magnetic resonance imaging (MR) from 3 to 4 days after STEMI. At 6 month after MI, all patients were admitted and underwent follow-up coronary angiography (CAG) and dobutamine stress cardiac MR and NT-proBNP levels were obtained. RESULTS: NT-proBNP levels at follow-up were significantly correlated with age (r=0,558 p<0.01), pain to door time and pain to balloon time (r=0.349, p<.05 vs. r=0.402, p=0.20), peak levels of troponin during MI period (0.724 p<0.001). Patients with culprit lesion on LAD , low TMP grade at follow-up had significant higher levels of NT-proBNP levels. MRI parameters of index for myocardial damage and LV remodeling, such as LV EF at follow-up (r=-0.726, p<0.001), wall motion score (r=0.745, p<0.01), infarct volume at follow-up (r=0.690, p<0.01) and LV dimension (LVEDV, r=0.767, p<0.001) were significantly correlated with follow-up NT-proBNP levels. The transmural extent of myocardial infartion and severity of microvascular obstruction at baseline cardiac MR were also significantly correlated with FU NT-proBNP levels (p<0.01). Conclusion: This study shows that in asymptomatic patients with STEMI treated with primary PCI, high NT-proBNP levels during follow-up are suggest large infarct size, progressed LV remodeling and transmurality of infarction , which suggest poor prognosis. So these findings explain that NT-proBNP may be exellent useful markers for long-term prognosis.