ABC | Volume 112, Nº4, April 2019

Original Article Ciuffo et al LA Remodeling and Dyssynchrony Arq Bras Cardiol. 2019; 112(4):441-450 Figure 5 – Intra-reader and inter-reader reproducibility – Bland-Altman plot. A, standard deviation of the time to peak strain (SD-TPS) intra-reader reproducibility. B, standard deviation of the time to peak pre-atrial strain (SD-TPS preA ) intra-reader reproducibility. C, SD-TPS inter-reader reproducibility. D, SD-TPS preA inter-reader reproducibility. R1: first reader; R2: second reader. .5 0 –.5 A B C D –.4 –.2 –.1 0 1 2 –.2 0 .2 .4 –2 –1 0 1 2 1 1.5 2 2.5 3 3 2 4 6 5 1.5 2 2.5 3 3 4 5 6 2 1 Difference SD–TPS (%) Difference (R1 - R2) SD–TPS (%) Difference SD–TPS preA (%) Difference (R1 - R2) SD–TPS preA (%) Mean SD–TPS (%) Mean SD–TPS preA (%) Mean (R1 + R2) SD–TPS (%) Mean (R1 + R2) SD–TPS preA (%) Table 4 – Inter-reader and intra-reader reproducibility of the left atrial measurements. Results are reported as mean ± standard deviation Inter-reader ICC p LA parameter Difference (mean ± SD) SD-TPS, % -0.05 ± 0.21 0.86 < 0.001 SD-TPS preA , % -0.09 ± 0.83 0.74 < 0.001 Intra-reader ICC p LA parameter Difference (mean ± SD) SD-TPS, % 0 ± 0.25 0.86 < 0.001 SD-TPS preA , % -0.03 ± 0.73 0.85 < 0.001 LA: left atrial; SD: standard deviation; ICC: intraclass correlation coefficient; TPS: time to peak strain; TPS preA : time to peak pre-atrial contraction strain. was no significant difference in LA‑LGE between patients with persistent and paroxysmal AF, although there was a trend for a larger extent of LA-LGE with persistent AF. A possible explanation to account for these results is that intra-atrial dyssynchrony likely reflects subtle changes in atrial architecture that could generate AF but is not captured by LGE or other indices of LA function. In fact, mechanical dyssynchrony was a more specific marker of AF recurrence after AF ablation when compared to LA scar and function (8). Technical difficulties associated with LA-LGE acquisition and processing may also account for the finding. For example, the thin wall of the LA (~3 mm) poses a challenge to the spatial resolution of CMR. In addition, only a small fraction of intravenously administered contrast perfuses the LA wall because the vast majority perfuses the ventricles 447