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Review
. 2020 Mar 2;10(3):137.
doi: 10.3390/diagnostics10030137.

Left Atrial Structural Remodelling in Non-Valvular Atrial Fibrillation: What Have We Learnt from CMR?

Mariana Floria  1   2 , Smaranda Radu  2   3 , Evelina Maria Gosav  2   4 , Dragos Cozma  5 , Ovidiu Mitu  2   6 , Anca Ouatu  2   4 , Daniela Maria Tanase  2   4 , Viorel Scripcariu  2   7 , Lacramioara Ionela Serban  2   8
Affiliations
Review

Left Atrial Structural Remodelling in Non-Valvular Atrial Fibrillation: What Have We Learnt from CMR?

Mariana Floria et al. Diagnostics (Basel). .

Abstract

Left atrial structural, functional and electrical remodelling are linked to atrial fibrillation (AF) pathophysiology and mirror the phrase "AF begets AF". A structurally remodelled left atrium (LA) is fibrotic, dysfunctional and enlarged. Fibrosis is the hallmark of LA structural remodelling and is associated with increased risk of stroke, heart failure development and/or progression and poorer catheter ablation outcomes with increased recurrence rates. Moreover, increased atrial fibrosis has been associated with higher rates of stroke even in sinus-rhythm individuals. As such, properly assessing the fibrotic atrial cardiomyopathy in AF patients becomes necessary. In this respect, late-gadolinium enhancement cardiac magnetic resonance (LGE-CMR) imaging is the gold standard in imaging myocardial fibrosis. LA structural remodelling extension offers both diagnostic and prognostic information and influences therapeutic choices. LGE-CMR scans can be used before the procedure to better select candidates and to aid in choosing the ablation technique, during the procedure (full CMR-guided ablations) and after the ablation (to assess the ablation scar). This review focuses on imaging several LA structural remodelling CMR parameters, including size, shape and fibrosis (both extension and architecture) and their impact on procedure outcomes, recurrence risk, as well as their utility in relation to the index procedure timing.

Keywords: atrial fibrillation; atrial fibrosis; cardiac magnetic resonance; structural remodeling.

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Conflict of interest statement

The authors declare no conflict of interest.

Figures

Figure 1
Figure 1
The bidirectional relationship between LA remodeling, atrial cardiomyopathy and atrial failure.
Figure 2
Figure 2
LGE-LA of 35.4% (Utah IV) in a persistent AF patient with repetitive ablations. Increased fibrosis at the posterior wall and pulmonary veins. Red demonstrates the presence of fibrosis. AF: atrial fibrillation; LGE-LA- late gadolinium enhancement in the left atrium.
Figure 3
Figure 3
Pre-ablation roles of LGE-CMR.* in terms of immediate sinus rhythm restoration and post-procedural arrhythmia recurrences. LA: left atrium; LGE-CMR: late-gadolinium enhancement cardiac magnetic resonance, Utah classes of fibrosis: Utah I: <10%, Utah II: 10%–20%, Utah III: 20%–30%, Utah IV: >30%.
Figure 4
Figure 4
The use of CMR imaging in relation to the timing of the index procedure (up, center- pre-ablation, down-left- peri-procedural and down-right- post-ablation). Preablation, the degree of structural remodeling can be assessed through LA volume, sphericity and fibrosis extension and disposition. New techniques are being explored to allow performing full CMR-guided ablation. Post-ablation, CMR is used immediately after the procedure to scan for possible complications and assess early scar formation. Later, CMR can be used to assess the degree of both reverse remodeling and residual fibrosis and describe the ablation lesions gaps. CMR: cardiac magnetic resonance; LA: left atrium; LAA: left atrial appendage; NE: non-enhancing.
See this image and copyright information in PMC

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