The spring stiffness coefficient of mitral inflow for aged B6J, MCP-1KO and B6N hearts. A, Representative images from aged B6J and B6N hearts showing E/A ratio for aged B6J and B6N hearts. N=10 per each group. B, Kovacs analysis of Doppler mitral early flow predicts left ventricular diastolic stiffness. N= 7, 4, 5 for aged B6J, aged MCP-1KO, and aged B6N respectively. 21–24 month-old mice were used. Data are presented as mean ± SEM.