Statistical analysis
We analyzed all data using SPSS 19.0 software (SPSS 19.0, Inc., Chicago, IL, USA). All continuous variables conforming to normal distribution were showed as mean values ± standard deviations. Comparisons of the gender among the three groups were made by using χ²-test. Differences of three groups were compared by analysis of one-way ANOVA. LSD-t test was used to compare the differences between two groups. For analyzing the correlations of NT-proBNP and LVEDP with 3D-STE parameters and in three groups, we used Pearson linear correlation analysis. The values of P<0.05 demonstrated that the results were statistically significance.