Statistical Analysis
A Paired T-Test was performed to test for a significant difference in group means of preprocedural LVEF and postprocedural LVEF. This section of analysis was done to determine if the mean ejection fraction was significantly different after the procedure. A Wilcoxon Signed-Rank Test was performed to see if the distribution of the before and after LVEF were symmetric about zero.
We then set out to determine if the location of the Micra had any significance in EF performance. Before performing our two-way ANOVA to test the significance of the group (implantation location) means in each of the EF states (before and after), we had to confirm homoscedasticity (homogeneity of variance), which would confirm that the variance around the mean was roughly equal in all groups. For this purpose, we employed the Bartlett Test, which confirmed that there was roughly equal variance in the before and after LVEF groups. We were then able to perform a two-way ANOVA test, an ANCOVA test, and a Fixed Effects Model to determine if the Micra implantation location had any significant effect on the LVEF.
Basic statistical analysis was also used to evaluate the impact of device implantation on the QRS, TR severity, and occurrence of PICM.