In the udenafil group , an echocardiographic surrogate of LV filling pressure was more prominently decreased ( P = 0.006 ) along with a significant reverse remodeling of left atrial volume index ( 57 25mL at baseline to 44 23 at 12th week , P = 0.04 ) and a progressive fall in B-type natriuretic peptide level ( 589 679pg/mL at baseline to 220 225pg/mL at 12th week , P < 0.001 ) , indicating LV diastolic function improvement .