A study was conducted to understand the effect of shear stresses on cell attachment and growth. Human cardiac fibroblasts were cultured on tissue culture slides for flow experiments. In order to monitor cell morphology and determine percentage coverage of surface cells, photographs were taken at time 0h, 4h, 24h, 48h, and 72h and 96h. The results suggest that human leaflet fibroblasts are able to remain adherent and proliferate under shear stresses encountered in cardiac sites in vivo. These data demonstrate the feasibility of developing tissue engineered heart valve leaflets under flow.