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

Diagnostics ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 137 ◽  
Author(s):  
Mariana Floria ◽  
Smaranda Radu ◽  
Evelina Maria Gosav ◽  
Dragos Cozma ◽  
Ovidiu Mitu ◽  
...  

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.

2019 ◽  
Vol 40 (Supplement_1) ◽  
Author(s):  
T A Agbaedeng ◽  
M Emami ◽  
D A Munawar ◽  
T Rattanakosit ◽  
K I Khadim ◽  
...  

Abstract Background Fibrosis is a hallmark of atrial fibrillation (AF) substrate. Recent data suggests that fibrosis detected by late-gadolinium enhancement (LGE) cardiac MRI (CMR) can predict AF. However, this relationship is not well described. Objective To delineate the association of cardiac fibrosis detected by LGE CMR with AF prevalence, AF recurrence after catheter ablation. Methods PubMed, Embase, Web of Science and Ovid MEDLINE were searched through November 2018, using the keywords: LGE AND Fibrosis AND CMR AND AF. Inclusion criteria: 1. LGE CMR of left atrial (LA LGE), ventricular wall (LV LGE) or right ventricular wall (RV LGE); 2. Studies reporting AF or recurrent arrhythmia after ablation; 3. Patient ≥18 years; and 4. ≥50 participants. Included studies were pooled in a random effects meta-analysis and reported as: mean difference (MD); unadjusted risk ratios (RR); adjusted hazard ratios (HR); and 95% confidence intervals (95% CI). Results After exclusions, we identified 9 studies (2,307 patients [65.9% males, 34.1% females]) conducted between 2003 and 2015 for LGE and AF. Fibrosis was present in 666 (35.1%) and detected by LV LGE in 7 (78%) and RV LGE in 2 (22%). The presence of AF was higher in patients positive for ventricular LGE than those negative, trending towards significance (RR: 1.51, 95% CI: 0.94–2.45, p=0.09). Pooled LV fibrosis associated with AF progression (RR [NPAF vs. PAF]: 2.2, 95% CI: 1.22–3.94, p=0.009). We identified 8 studies (2,041 patients [65.8% males, 34.2% females]) conducted between 2006 and 2016 reporting LGE and AF recurrence after catheter ablation, with fibrosis detected in 644 (31.6%) by LA LGE in 8 (88.9%, biased towards one centre). After 17.8±14.2 follow-up years, atrial fibrosis was significantly greater in recurrent AF than controls (MD: 4.97%, 95% CI: 1.23–8.7, p<0.01), and predicted 16% increased risk of AF recurrence (RR: 1.16, 95% CI: 1.07–1.26, p<0.05). Conclusion Myocardial fibrosis detected by LGE associates with prevalence and progress of AF and is predictive of AF recurrence post ablation. This further supports the proarrhythmic role of fibrosis and selection of patients for ablation therapy based on LGE.


EP Europace ◽  
2020 ◽  
Vol 22 (Supplement_1) ◽  
Author(s):  
M Eichenlaub ◽  
H Lehrmann ◽  
B Mueller-Edenborn ◽  
J Allgeier ◽  
R Weber ◽  
...  

Abstract Background/Introduction Left atrial (LA) fibrosis is associated with increased arrhythmia recurrence rates after pulmonary vein isolation (PVI) and increased stroke risk in patients with atrial fibrillation (AF). So far, detection and quantification of LA fibrosis is only feasible by invasive electrophysiological mapping of low-voltage-substrate (LVS) or delayed enhancement areas in MRI. Purpose The aim of this study was to assess the distribution and extent of atrial fibrosis by non-invasive ECG-Imaging (ECGI) in patients with persistent AF prior to PVI. Methods Thirty-seven consecutive patients (66 ± 9 years, 84% male) presenting for their first PVI were included. Patients with AF were cardioverted into sinus rhythm (SR). One day prior to AF ablation procedure, patients underwent ECGI in SR using the 252-electrode-array (CardioInsight) and a low-X-ray-dose, non-injected cardiac CT-scan to assess the relationship between ECGI-electrodes and cardiac epicardial structures. Prior to PVI, high-density biatrial voltage and activation maps were acquired in SR (CARTO-3). Localization and extent of atrial LVS (relevant fibrosis: LA-LVS: ≥5cm2 at &lt;0.5mV threshold) and biatrial activation times depicted by CARTO were compared with atrial activation/conduction times assessed by non-invasive ECGI.  Presence of LA-LVS was classified according to its extent into 3 stages and compared to the inter- and intraatrial conduction delay in ECGI. Results Relevant atrial fibrosis was found in 17/37(46%) patients. Presence of biatrial LVS resulted in a linear increase of the biatrial activation time in CARTO-SR-maps (146 ± 18ms in patients without LVS vs 184 ± 27ms in patients with LVS, p &lt; 0.001) and in non-invasive ECGI (133 ± 11ms vs 170 ± 20ms, p &lt; 0.001). Both the extent of biatrial LVS and invasively measured total activation time correlated well with non-invasive total atrial conduction time (TACT) in ECGI (r = 0.91 and r = 0.82, respectively, figure). Moreover, the extent of LA-LVS showed an excellent correlation to TACT in ECGI (r = 0.89). A combination of inter-atrial (RA-LA) conduction delay and TACT in ECGI allowed to quantify the extent of LA-LVS and to distinguish between three stages of LA-LVS: Stage 1 (minimal LA-LVS: 1 ± 2cm2): ECGI revealed rapid RA&LA activation with short TACT 132 ± 9ms; Stage 2 (moderate LA-LVS: 14 ± 8cm2 involving the anteroseptal LA) was associated with delayed LA activation and prolonged TACT measuring 161 ± 7ms; Stage 3 (extensive LA-LVS involving the anteroseptal and posterior LA: 26 ± 17cm2) was characterized by a significantly delayed LA activation with a TACT of 178 ± 24ms in ECGI. Conclusion Analysis of interatrial conduction delay and total atrial conduction time (TACT) in non-invasive ECGI allows accurate staging of patients with arrhythmogenic atrial LVS who present an increased risk for arrhythmia recurrences and stroke. Abstract Figure.


Circulation ◽  
2008 ◽  
Vol 118 (suppl_18) ◽  
Author(s):  
Jeongjoo Woo ◽  
Dana C Peters ◽  
John V Wylie ◽  
Reza Nezafat ◽  
Thomas H Hauser ◽  
...  

Introduction: There is increasing evidence for and interest in detecting electrically silent left atrial (LA) myocardium which may be the substrate of atrial fibrillation (AF). Late gadolinium enhancement (LGE) cardiovascular magnetic resonance (CMR) might detect these areas of pre-existent scar as high signal in the LA wall. We sought to correlate the extent low-voltage areas in AF patients with clinical parameters of LA volume and type of AF, and to correlate areas of low voltage with areas of high signal on LGE CMR, indicating areas of scarred tissue. Methods: Twenty-two patients with AF underwent high resolution atrial LGE CMR on a 1.5 T CMR scanner and bipolar voltage electroanatomic mapping (Carto, Biosense Webster). The number of the LA mapping points with low (< 0.1mV) voltage was calculated for each patient. LA systolic volume was measured, indexed to BSA. Using the voltage maps, blood-LA contrast to noise ratio (CNR) was measured on the LGE CMR images in two areas, low and high voltage areas (N=10). Hypothesis testing used t-tests and p<0.05. Results: The average extent of LA low voltage was 8 % of the LA. Four (18%) patients had no low voltage regions. The extent of low voltage for patients with non-paroxysmal vs. paroxysmal AF was 11 ± 13% vs. 4 % ± 5 % (p=0.08). The extent of low voltage for patients with larger than median LA volumes vs. smaller LA volumes was 12 ± 13% vs. 1 ± 1 % (p=0.027). In 10 patients in which LGE was measured in low and high voltage regions, the CNR was 10 vs. 6 (p=0.016). Conclusions: Patients with extensive low voltage regions in the LA have larger LA volumes. The CNR is higher in low-voltage regions, suggesting that such regions of possible scar can be identified by LGE CMR. This research has received full or partial funding support from the American Heart Association, AHA National Center.


BMJ Open ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. e044695
Author(s):  
Mu Chen ◽  
Qunshan Wang ◽  
Jian Sun ◽  
Peng-Pai Zhang ◽  
Wei Li ◽  
...  

IntroductionIt is the common clinical practice to prescribe indefinite aspirin for patients with non-valvular atrial fibrillation (NVAF) post left atrial appendage occlusion (LAAO). However, aspirin as a primary prevention strategy for cardiovascular diseases has recently been challenged due to increased risk of bleeding. Therefore, aspirin discontinuation after LAAO in atrial fibrillation (ASPIRIN LAAO) trial is designed to assess the uncertainty about the risks and benefits of discontinuing aspirin therapy at 6 months postimplantation with a Watchman LAAO device in NVAF patients.Methods and analysisThe ASPIRIN LAAO study is a prospective, multicentre, randomised, double-blinded, placebo-controlled non-inferiority trial. Patients implanted with a Watchman device within 6 months prior to enrollment and without pre-existing conditions requiring long-term aspirin therapy according to current guidelines are eligible for participating the trial. Subjects will be randomised in a 1:1 allocation ratio to either the Aspirin group (aspirin 100 mg/day) or the control group (placebo) at 6 months postimplantation. A total of 1120 subjects will be enrolled from 12 investigational sites in China. The primary composite endpoint is stroke, systemic embolism, cardiovascular/unexplained death, major bleeding, acute coronary syndrome and coronary or periphery artery disease requiring revascularisation at 24 months. Follow-up visits are scheduled at 6 and 12 months and then every 12 months until 24 months after the last patient recruitment.Ethics and disseminationEthics approval was obtained from the Ethics Committee of Xinhua Hospital, Shanghai, China (reference number XHEC-C-2018-065-5). The protocol is also submitted and approved by the institutional Ethics Committee at each participating centre. Results are expected in 2024 and will be disseminated through peer-reviewed journals and presentations at national and international conferences.Trial registration numberNCT03821883.


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