ABC | Volume 112, Nº4, April 2019

Original Article Ciuffo et al LA Remodeling and Dyssynchrony Arq Bras Cardiol. 2019; 112(4):441-450 via the coronary arteries. Our result also showed that the LA intra-atrial dyssynchrony analysis is less time‑consuming (5 ± 9 minutes) than LA-LGE (60 ± 20 minutes). This finding suggests that the implementation of LA intra-atrial dyssynchrony analysis in routine clinical practice would not significantly impede the clinical workflow of preprocedural assessment. The possibility that cardioversion-induced atrial stunning could have confounded our findings is low because: 1) cardioversion was performed in only a minority of patients in both groups and 2) there was no significant difference in the fraction of patients who underwent cardioversion between both groups. LA dyssynchrony reproducibility Our results showed excellent intra-reader reproducibility of LA intra-atrial dyssynchrony, with ICC ranging from 0.74 to 0.86 for SD-TPS, and 0.85 to 0.95 for SD-TPS preA , with the mean difference of 0 and -0.03, respectively (Table 4, Figure 5). The inter-reader reproducibility was also excellent to good, with ICC ranging from 0.86 for SD-TPS and 0.74 for SD-TPS preA , with the mean difference of -0.05 and -0.09, respectively (Table 4, Figure 5). Both intra-reader and inter‑reader reproducibility were similar to the values described in studies using 2D and 3D echocardiography. 17 Limitations This study accounts for a single-center, retrospective, cross-sectional analysis of patients referred for PVI to treat drug-refractory AF in a tertiary center. Therefore, there is a non-negligible chance of selection bias. For the dyssynchrony analysis, we used only two- and four-chamber cine CMR, which was included in a routine image-acquisition protocol. Therefore, it is possible that our analysis underestimated the degree of dyssynchrony by missing regions that were not covered by those two views. Since the strain was 2D and was obtained only in the in-plane direction, the strain values may have been underestimated compared with those in 3D strains. Besides, the CMR temporal resolution may also explain our lower values of dyssynchrony compared to echocardiography. 17 There is a chance of underestimation of dyssynchrony due to spontaneous restoration of sinus rhythm a few weeks before the CMR. However, we believe that this fact would happen more often in individuals with paroxysmal AF; thus, our findings may have underestimated the real difference in dyssynchrony between individuals with paroxysmal and persistent AF by underestimating the dyssynchrony in the paroxysmal group. Finally, we had to exclude subjects who were not in sinus rhythm by the time of the cine image acquisition, which could be a limitation for the application of our method in subjects with persistent AF. Conclusions LA intra-atrial dyssynchrony is significantly associated with LA-LGE independent of traditional cardiovascular risk factors or LA structure and function. Moreover, LA intra‑atrial dyssynchrony was greater in individuals with persistent AF than in those with paroxysmal AF, whereas LA-LGE was not significantly different between the two AF types. LA intra-atrial dyssynchrony is a reproducible index to quantify LA remodeling and is less time-consuming than LA-LGE. Intra-atrial dyssynchrony can be used as a surrogate for the underlying tissue remodeling in patients with AF. Author contributions Conception and design of the research: Ciuffo LA, Lima J, Ashikaga H; Acquisition of data na Statistical analysis: Ciuffo LA; Analysis and interpretation of the data: Ciuffo LA, Tao S; Obtaining financing: Ashikaga H; Writing of the manuscript: Ciuffo LA, Ashikaga H; Critical revision of the manuscript for intellectual content: Lima J, Balouch M, Tao S, Nazarian S, Marine JE, Calkins H, Ashikaga H, Vasconcellos HD, Spragg DD, Berger RD. Potential Conflict of Interest No potential conflict of interest relevant to this article was reported. Sources of Funding There were no external funding sources for this study. Study Association This study is not associatedwith any thesis or dissertationwork. Ethics approval and consent to participate This study was approved by the Ethics Committee of The Johns Hopkins IRB under the protocol number CIR0004531. All the procedures in this study were in accordance with the 1975 Helsinki Declaration, updated in 2013. Informed consent was obtained from all participants included in the study. 448