Statistical analysis
The Kolmogorov-Smirnov test was used to verify the normal distribution of continuous variables. Variables with normal distribution were described by means and standard deviations and compared by paired Student’s t-test. For comparison of the mean LVEF after 6 months between the groups, the unpaired t test was performed. Non-parametric variables were described as medians and interquartile range and compared with the the Wilcoxon test. Categorical data were presented as the number of patients and percentage of the total sample and were compared by the Fisher’s exact test. The overall survival was calculated by the Kaplan-Meier method and the log-rank test was used to compare the survival curves. A value of P <0.05 was considered as statistically significant. To identify the variables that are independently predictive of overall mortality, a subsequent stepwise multivariate analysis using Cox’s regression model was performed, including variables that had a predictive value of P-value < 0.10 in the univariate analysis of overall survival (log-rank test). The Statistical Package for the Social Sciences (SPSS) version 20.0 was used for the analysis of all data.