Statistical analysis: The SPSS software (version 12) will be used for all statistical analyses. All continuous variables are presented as means ± standard deviation. Analysis of variance and post hoc test (Scheffe F-test) for unpaired data are used to evaluate the significance of differences between groups. A p vale of < 0.05 is considered statistically significant. Comparison of clinical characteristics is performed by chi-square analysis for categorical variables. Bivariate analysis, simple correlation and linear regression are used as appropriate. The relation curve between LA distensibility and LV filling pressure are estimated using SPSS software. ROC curve analysis is also performed to assess the sensitivity and specificity of the cut-off points of echocardiographic parameters when predicting elevated LV filling pressure (> 15 mmHg), and the presence of the above-mentioned events. If LA distensibility is useful for predicting elevated LV filling pressure and major events, Kaplan-Meier curve will be performed to assess the cumulative event-free rate according to the cut-off point of LA distensibility estimated by ROC curve. The hazards ratios of clinical and echocardiographic parameters, including LA distensibility will be assessed by multivariate logistic analysis.