ABC | Volume 112, Nº4, April 2019

Original Article Intra-Atrial Dyssynchrony Using Cardiac Magnetic Resonance to Quantify Tissue Remodeling in Patients with Atrial Fibrillation Luisa Allen Ciuffo, 1, 2 João Lima, 3 Henrique Doria de Vasconcellos, 2 M uhammad Balouch, 2 Susumu Tao, 2 Saman Nazarian, 2 David D. Spragg, 2 Joseph E. Marine, 2 Ronald D. Berger, 2 Hugh Calkins, 2 Hiroshi Ashikaga 2 University of New Mexico, 1 New Mexico – USA The Johns Hopkins University, 2 Baltimore – USA Johns Hopkins Hospital and Health System, 3 Baltimore – USA Mailing Address: Luisa Allen Ciuffo • University of New Mexico, 2211. 87131-1466, Lomas Blvd NE Albuquerque, Novo México – USA E-mail: iallem@hotmail.com Manuscript received October 21, 2018, revised manuscript January 05, 2019, accepted January 21, 2019 DOI: 10.5935/abc.20190064 Abstract Background: Recent studies suggest that left atrial (LA) late gadolinium enhancement (LGE) can quantify the underlying tissue remodeling that harbors atrial fibrillation (AF). However, quantification of LA-LGE requires labor-intensivemagnetic resonance imaging acquisition and postprocessing at experienced centers. LA intra-atrial dyssynchrony assessment is an emerging imaging technique that predicts AF recurrence after catheter ablation. We hypothesized that 1) LA intra-atrial dyssynchrony is associated with LA-LGE in patients with AF and 2) LA intra-atrial dyssynchrony is greater in patients with persistent AF than in those with paroxysmal AF. Method: We conducted a cross-sectional study comparing LA intra-atrial dyssynchrony and LA-LGE in 146 patients with a history of AF (60.0 ± 10.0 years, 30.1% nonparoxysmal AF) who underwent pre-AF ablation cardiac magnetic resonance (CMR) in sinus rhythm. Using tissue‑tracking CMR, we measured the LA longitudinal strain in two- and four-chamber views. We defined intra-atrial dyssynchrony as the standard deviation (SD) of the time to peak longitudinal strain (SD-TPS, in %) and the SD of the time to the peak pre-atrial contraction strain corrected by the cycle length (SD-TPS preA , in %). We used the image intensity ratio (IIR) to quantify LA-LGE. Results: Intra-atrial dyssynchrony analysis took 5 ± 9 minutes per case. Multivariable analysis showed that LA intra-atrial dyssynchrony was independently associated with LA-LGE. In addition, LA intra-atrial dyssynchrony was significantly greater in patients with persistent AF than those with paroxysmal AF. In contrast, there was no significant difference in LA-LGE between patients with persistent and paroxysmal AF. LA intra-atrial dyssynchrony showed excellent reproducibility and its analysis was less time-consuming (5 ± 9 minutes) than the LA-LGE (60 ± 20 minutes). Conclusion: LA Intra-atrial dyssynchrony is a quick and reproducible index that is independently associated with LA-LGE to reflect the underlying tissue remodeling. (Arq Bras Cardiol. 2019; 112(4):441-450) Keywords: Heart Atria; Atrial Fibrillation; Diagnostic Imaging; Echocardiography/methods; Magnetic Resonance Spectroscopy. Introduction Atrial fibrillation (AF) is the most prevalent arrhythmia 1 and an independent predictor of stroke 2 and dementia. 3 The cornerstone treatment for drug-refractory AF is invasive catheter ablation with pulmonary vein isolation (PVI), but the rate of recurrence after PVI is relatively high. 4 Preprocedural assessment of left atrial (LA) late gadolinium enhancement (LGE) is a predictor of AF recurrence after PVI. 5,6 LA-LGE can be considered as a surrogate for the underlying tissue remodeling represented by fibrotic replacement that promotes AF. Although LA‑LGE has a potential to improve the clinical outcomes of PVI by refining patient selection, its major limitation is the requirement of labor-intensive magnetic resonance imaging (MRI) acquisition and postprocessing, which are not always compatible with clinical workflow. In addition, LA-LGE requires intravenous contrast administration, which is contraindicated in subgroups of PVI candidates, such as individuals with renal failure or allergic reactions to gadolinium-based contrast materials. As a result, LA‑LGE is not part of the standard clinical practice, except at experienced centers. 7 Recently, we demonstrated that preprocedural assessment of LA intra-atrial dyssynchrony predicts AF recurrence after PVI. 8 The assessment utilizes a tissue-tracking technology that can be applied to any routinely acquired cine MRI, which does not require intravenous contrast administration. 9 It is simple and quick, only based on two long-axis views (two-chamber and four-chamber views) of routine cine MRI. Because the LA structure and function reflect the underlying tissue fibrosis, 10 it is possible that LA intra-atrial dyssynchrony serves as a surrogate for LA-LGE. In this study, we hypothesized that LA intra-atrial dyssynchrony is associated with LA-LGE in patients with AF. In addition, we further hypothesized that LA intra-atrial dyssynchrony is greater in patients with persistent AF than 441