Background and Objectives : The resting mean pressure gradients through the aortic valve were commonly observed in the smallest 19 mm prosthetic aortic valve (PAV) even though the valve did not have any dysfunction. Therefore, we sought to evaluate the echocardiographic findings in patients of normal 19-mm PAV with higher mean pressure gradients. Materials and Methods : Tweenty patients (mean age 52 짹 12 years, 16 females) without clinical or hemodynamic evidence of valve dysfunction underwent 19-mm PAV replacement were allocated to two groups based on the mean pressure gradients (group 1: > 25 mmHg, higher gradients, n=9, group 2: < 25 mmHg, lower gradients, n=11). We evaluated the 2-D and Doppler echocardiographic findings including Doppler velocity index (DVI). DVI was defined as peak velocity in left ventricular (LV) outflow tract divided by that of aortic jet. To find out the factors that can affect the pressure gradients through the PAV, we compared the echcardiographic parameters such as LV ejection fraction (EF), LV end diastolic volumes (LVEDV), LV mass index (LVMI), and effective prosthetic valve area (EOA) in two groups. Results : The mean time interval from valve replacement to echocardiographic examination was 37 짹 27 months. DVI ranged between 0.28 to 0.65 (mean, 0.40 짹 0.12). In patients of group 1, LVEDV, LVMI, and DVI were greater than in group 2 (133 짹 16 versus 136 짹 16 ml, p=0.323, 123 짹 14 versus 103 짹 23 g/m2, p=0.037, and 0.42 짹 0.07 versus 0.34 짹 0.05, p=0.035). EOA in patients of group 1 were significantly lower than that in group 2 (0.97 짹 0.15 versus 1.28 짹 0.21, p=0.002). LVEF were similar between two groups. Conclusion : For the evaluation of patients with 19-mm PAV with higher pressure gradients but normal DVI, increased LV mass index and smaller effective prosthetic valve area could be considered.