Background: N-Terminal Pro-Brain Natriuretic Peptide(NT-proBNP) was introduced recently for useful predictors for cardiac events in acute coronary syndrome(ACS). But there was no report about specific relations with myocardial viability and left ventricular(LV) diastolc function in early phase of ACS reflecting chamber remodeling. So we studied about association of initial NT-proBNP and Myocardial Viability, LV end diastolic pressure(LVEDP) and noninvasive diastolic parameters by transthoracic echocardiography in in early phase of ACS patients. Methods: Seventeen consecutive patients with ACS was measured NT-proBNP at time of arrival in the emergency room and underwent low-dose dobutamine echocardiography(LD-DSE; upto 10mcg/kg/min) to assess myocardial viability on 5~9 days after event. Myocardial viability was quantitatively evaluated by change of peak systolic strain rate(psSR), percent change of time to onset of regional relaxation(TR) and wall motion score index(WMSI). Various Doppler echocardiographic parameters and left atrial volume was measured on the study. And at the same day just after the study, left heart catheterization with recording of LVEDP was performed. Results: Patients (59% Male; mean age 63짹11 years) showed moderately decreased LV systolic functions(EF=42.3짹13.4%) and elevated LVEDP(25.9짹8.3mmHg). NT-proBNP levels ranged from 51 to 15079 ng/L, with a median of 1382ng/L (interquatile range, 834 to 1869ng/L). NT-proBNP showed significantly correlated with transmitral peak E velocity/mitral annular E��� velocity(E/E���) and systolic fraction of pulmonary venous flow ( r=0.584 and P=0.014 and r=-0.512 and P=0.043, respectively). And also NT-proBNP showed distinct but statistically insignificant linear correlation with LVEDP, left atrial volume, and propagation velocity fron color M mode of transmitral flow(r=-0.332, p=0.210 r=0.407 and P=0.105 and r=0.402 and P=0.110, respectively). But NT-proBNP showed weak and insignificant correlation with percent change of TR , WMSI and psSR. Conclusions; Initial NT-proBNP significantly correlates with LV diastolic parameters in early phase of ACS and may be useful predictors for assessing LV remodelling.