Fig. 3

Bland-Altman analysis for inter-observer variability (a) and inter-observer variability (b) of left atrial strain and strain ratio indexes measurements. Solid line represents bias and dotted lines represent 95% limits of agreement for measurements performed in 20 patients. The bias was assessed by the mean of 20 differences of two measurements. The 95% confidence interval was calculated as ±1.96 SDs from the mean. Overall, small differences were observed for all left atrial strain and strain ratio indexes measurements because most of the differences were within the range of 95% limits of agreement, which suggesting good repeatability and reproducibility in LA strain and strain ratio indexes. Cond, atrial conduit phase; PALS, peak atrial longitudinal strain; PALSR, peak atrial longitudinal strain rate; pump, atrial booster pump phase; res, atrial reservoir phase; TpS-SD%, the standard deviation of time to peak atrial longitudinal strain corrected by RR interval; TpSR-SD%, the standard deviation of time to peak atrial longitudinal strain rate corrected by RR interval