Agreement on LVEF and wall motion abnormalities assessed by TTE and HHU:
To measure the agreement level, the concordance correlation coefficient (r) was calculated for both TTE and HHU (Fig 1A). The r-value for LVEF between the standard TTE and HHE was 0.71 (95% confidence interval [CI]: 0.58 to 0.81, p value < 0.0001). Figure 1C shows the Bland-Altman plot for agreement between HHE and TEE for assessing LVEF: the majority of measurements fell within the 95% confidence interval indicating the high agreement between the two methods.
The concordance correlation coefficient for WMSI between the standard TTE and HHE was 0.76 (95% CI: 0.65 to 0.84, p value < 0.0001) (Fig 1B). Similarly, a Bland-Altman graph generated from the WMSI data showed that majority of measurements for wall motion abnormalities were seen within the range of the 95% confidence interval (Fig 1D). The largest difference in WMSI between the HHU and standard TTE occurred in the mid to upper to end of the reported range, between 1.5 and 2.5.
We also calculated the agreement for the presence of segmental regional wall-motion abnormalities between the HHU and standard TTE for each of the 16 segments of left ventricle. Agreement was variable among different LV segments with r-values ranging between 0.48 to 0.80. It was highest for the mid inferoseptal wall (0.80) on apical view and mid inferolateral wall (0.77) on parasternal long axis, and lowest for the basal anterior (0.5) and basal inferior (0.51) walls on parasternal short axis views (Table 2).