Objective: To compare the hemodynamic effect of aortic Allcarbon and Bicarbon valves on the regressionof left ventricular mass index after 6 months of aortic valve replacement in patients with isolated aortic stenosis. Design: We studied 47 patients retrospectively who underwent mechanical aortic valve replacement at the Heart Institute of HoChiMinh City between January 1996 and December 1998: 31 patiens in Allcarbon group and 16 patients in Bicarbon group.