Atrial Fibrosis and Atrial Fibrillation: A Computer Simulation in the Posterior Left Atrium

2013 ◽  
pp. 400-408 ◽  
Author(s):  
Jichao Zhao ◽  
Robert S. Stephenson ◽  
Greg B. Sands ◽  
Ian J. LeGrice ◽  
Henggui Zhang ◽  
...  
Keyword(s):  
Atrial Fibrillation ◽  
Computer Simulation ◽  
Left Atrium ◽  
Atrial Fibrosis

scholarly journals Increased serum lysyl oxidase-like 2 levels correlate with the degree of left atrial fibrosis in patients with atrial fibrillation

2017 ◽  
Vol 37 (6) ◽  
Author(s):  
Yingming Zhao ◽  
Kangting Tang ◽  
Xu Tianbao ◽  
Junhong Wang ◽  
Jin Yang ◽  
...  
Keyword(s):  
Atrial Fibrillation ◽  
Left Atrium ◽  
Left Atrial ◽  
Cardiac Fibrosis ◽  
Lysyl Oxidase ◽  
Multivariate Regression Analysis ◽  
Enzyme Linked Immunosorbent Assay ◽  
Control Group ◽  
Atrial Fibrosis ◽  
Left Atrial Fibrosis

Atrial fibrillation (AF) progression is generally accompanied by increased atrial fibrosis and atrial structural remodeling. Lysyl oxidase-like 2 (LOXL2) is known to play an important role in many fibrotic conditions, including cardiac fibrosis. The present study aimed to explore the relationship between serum LOXL2 levels and AF. Fifty-four AF patients and 32 control subjects were enrolled in the study. High-density three-dimensional electroanatomic mapping was performed, and mean bipolar voltage was assessed in AF patients. LOXL2 levels were measured by enzyme-linked immunosorbent assay. All patients underwent echocardiography to assess left atrium size and left ventricle function. Serum LOXL2 levels were significantly elevated in AF patients compared with the control group (526.81 ± 316.82 vs 240.94 ± 92.51 pg/ml, P<0.01). In addition, serum LOXL2 level was significantly correlated with the size of the left atrium (LAD) (r2 = 0.38, P<0.01). Furthermore, the serum LOXL2 levels were significantly higher in AF patients with LAD ≥ 40 mm compared with those with LAD < 40 mm (664.34 ± 346.50 vs 354.90 ± 156.23 pg/ml, P<0.01). And the Spearman’s correlation analysis further revealed that the mean bipolar left atrial voltage was inversely correlated with the LOXL2 (r2 = −0.49, P<0.01) in AF patients. Multivariate regression analysis further demonstrated that serum LOXL2 [odds ratio (OR) 1.013, 95% confidence interval (CI) 1.002–1.024, P<0.05] and LAD (OR 1.704, 95% CI 1.131–2.568, P<0.01) were independent predictors of AF. In conclusion, serum LOXL2 levels were significantly elevated and were correlated with the degree of left atrial fibrosis in AF patients.

Fibrosis, atrial fibrillation and stroke: clinical updates and emerging mechanistic models

Heart ◽  
2020 ◽  
Vol 107 (2) ◽  
pp. 99-105 ◽  
Author(s):  
Patrick M Boyle ◽  
Juan Carlos del Álamo ◽  
Nazem Akoum
Keyword(s):  
Risk Factors ◽  
Atrial Fibrillation ◽  
Blood Flow ◽  
Left Atrium ◽  
Computational Models ◽  
Thrombus Formation ◽  
Computational Modelling ◽  
Clinical Risk Factors ◽  
Atrial Fibrosis ◽  
Clinical Risk

The current paradigm of stroke risk assessment and mitigation in patients with atrial fibrillation (AF) is centred around clinical risk factors which, in the presence of AF, lead to thrombus formation. The mechanisms by which these clinical risk factors lead to thromboembolism, including any role played by atrial fibrosis, are not understood. In patients who had embolic stroke of undetermined source (ESUS), the problem is compounded by the absence of AF in a majority of patients despite long-term monitoring. Atrial fibrosis has emerged as a unifying mechanism that independently provides a substrate for arrhythmia and thrombus formation. Fibrosis-based computational models of AF initiation and maintenance promise to identify therapeutic targets in catheter ablation. In ESUS, fibrosis is also increasingly recognised as a major risk factor, but the underlying mechanism of this correlation is unclear. Simulations have uncovered potential vulnerability to arrhythmia induction in patients who had ESUS. Likewise, computational models of fluid dynamics representing blood flow in the left atrium and left atrium appendage have improved our understanding of thrombus formation, in particular left atrium appendage shapes and blood flow changes influenced by atrial remodelling. Multiscale modelling of blood flow dynamics based on structural fibrotic and morphological changes with associated cellular and tissue electrical remodelling leading to electromechanical abnormalities holds tremendous promise in providing a mechanistic understanding of the clinical problem of thromboembolisation. We present a review of clinical knowledge alongside computational modelling frameworks and conclude with a vision of a future paradigm integrating simulations in formulating personalised treatment plans for each patient.

scholarly journals Associations Between Cardiac Fibrosis and Permanent Atrial Fibrillation in Advanced Heart Failure

2013 ◽  
pp. 247-255 ◽  
Author(s):  
B. ALDHOON ◽  
T. KUČERA ◽  
N. SMORODINOVÁ ◽  
J. MARTÍNEK ◽  
V. MELENOVSKÝ ◽  
...  
Keyword(s):  
Heart Failure ◽  
Atrial Fibrillation ◽  
Growth Factor ◽  
Heart Transplantation ◽  
Left Atrium ◽  
Wall Stress ◽  
Advanced Heart Failure ◽  
Right Atrial ◽  
Atrial Fibrosis ◽  
The Right

Atrial fibrosis is considered as the basis in the development of long-standing atrial fibrillation (AF). However, in advanced heart failure (HF), the independent role of fibrosis for AF development is less clear since HF itself leads to atrial scarring. Our study aimed to differentiate patients with AF from patients without AF in a population consisting of patients with advanced HF. Myocardial samples from the right atrial and the left ventricular wall were obtained during heart transplantation from the explanted hearts of 21 male patients with advanced HF. Long-standing AF was present in 10 of them and the remaining 11 patients served as sinus rhythm controls. Echocardiographic and hemodynamic measurements were recorded prior to heart transplantation. Collagen volume fraction (CVF), transforming growth factor-beta (TGF-β), and connective tissue growth factor (CTGF) expression in myocardial specimens were assessed histologically and immunohistochemically. The groups were well matched according to age (51.9±8.8 vs. 51.3±9.3 y) and co-morbidities. The AF group had higher blood pressure in the right atrium (13.6±7.7 vs. 6.0±5.0 mmHg; p=0.02), larger left atrium diameter (56.1±7.7 vs. 50±5.1 mm; p=0.043), higher left atrium wall stress (18.1±2.1 vs. 16.1±1.7 kdynes/m2; p=0.04), and longer duration of HF (5.0±2.9 vs. 2.0±1.6 y, p=0.008). There were no significant differences in CVF (p=0.12), in CTGF (p=0.60), and in TGF-β expression (p=0.66) in the atrial myocardium between the two study groups. In conclusions, in advanced HF, atrial fibrosis expressed by CVF is invariably present regardless of occurrence of AF. In addition to atrial wall fibrosis, increased wall stress might contribute to AF development in long-standing AF.

P1010Association between left atrial fibrosis detected by cardiac magnetic resonance and endocardial electroanatomic mapping in the evaluation of the electrophysiological substrate in atrial fibrillation

EP Europace ◽  
2020 ◽  
Vol 22 (Supplement_1) ◽  
Author(s):  
G Caixal ◽  
F Alarcon ◽  
M Nunez ◽  
P Garre ◽  
D Soto ◽  
...  
Keyword(s):  
Atrial Fibrillation ◽  
Magnetic Resonance ◽  
Left Atrium ◽  
Conduction Velocity ◽  
Left Atrial ◽  
Inverse Correlation ◽  
High Density ◽  
Atrial Fibrosis ◽  
Reproducible Method ◽  
Left Atrial Fibrosis

Abstract Background Atrial fibrillation (AF) is related to left atrial fibrosis, but its identification by late magnetic resonance imaging (LGE) with gadolinium (LGE) persists in controversy due to heterogeneous results in its correlation with the electroatomic map (EAM) and the difficulty of perform histological studies in humans. Purpose We try to examine the point-by-point association between high density EAM and LGE-MRI using an automatic and reproducible method. Methods A LGE-MRI was performed in 16 patients prior to ablation. Three different areas were established depending on the intensity of normalized enhancement for each patient according to their blood group with the image intensity ratio (IIR) (healthy &lt;1.20, border area (BZ) ≥1.20 &lt;1.32 and scar ≥1.32). The high density electroanatomic maps of the left atrium (LA) were projected onto the MRI, obtaining an automatic correlation point by point. Results The study obtained significant differences (p &lt; 0.001) between voltage (mV) and CV (mm/ms) among healthy, BZ and scar areas, as well a significant inverse correlation (p &lt; 0.001) between voltage and IIR (R=-0.39). It obtained too a significant correlation between CV and IIR (R=-0.24), but this showed a greater correlation in those patients who have the least dilated LA (p = 0.02). Conclusions LGE-MRI and EAM showed good correlation in delineating potential pathologic substrate in AF, but left atrium dilation could reduce the performance of the CMR in this task. Conduction velocity could be more sensitive than voltage and LGE-MRI to detect incipient substrate in AF. Voltage and conduction velocity values Area /IIR Velocity (mm/ms) Voltage (mV) I / &lt;.20 1.036(0.913-1.158) 1.593(1.489-1.696) 2 / ≥1.20 and &lt;1.32 0.722(0.590-0.850) 0.792 (0.649-0,935) 3 / ≥1.32 0.623(0.473-0,733) 0.444(0.245-0.642) Voltage and conduction velocity values in the three areas of the LGE-RMN. Abstract Figure. Correlation among voltage, VC and LA

Abstract 17049: Computer Simulation to Study the Effect of Structural Remodeling on Atrial Fibrillation Using Clinically-obtained Cardiac MRIs

Circulation ◽  
2015 ◽  
Vol 132 (suppl_3) ◽  
Author(s):  
Jason Ng ◽  
Justin K Ng ◽  
Paras Parikh ◽  
Jeffrey J Goldberger ◽  
Michael Markl ◽  
...  
Keyword(s):  
Atrial Fibrillation ◽  
Computer Simulation ◽  
Magnetic Resonance ◽  
Left Atrium ◽  
Computer Model ◽  
Potential Model ◽  
Diffuse Fibrosis ◽  
Structural Remodeling ◽  
Simulation Based ◽  
Anchor Points

Introduction: Structural remodeling of the atria in the form of fibrosis is known to be a contributing factor for the initiation and maintenance of atrial fibrillation (AF). Hypothesis: Using computer simulation based on clinically-obtained MRIs, we tested the hypothesis that both dense and diffuse fibrosis play significant roles in the inducibility of AF and the effectiveness of pulmonary vein (PV) ablation. Methods: Magnetic resonance angiograms and delayed enhancement MRIs (DEMRIs) of the left atrium from 34 AF patients were used to construct the models for the computer simulations. Using the Fenton-Karma action potential model, three conditions were tested for AF inducibility: 1) no fibrosis, 2) diffuse fibrosis, and 3) diffuse and dense fibrosis. AF induction was attempted at each of the four PVs and episodes lasting >30 s were considered sustained. Wide area PV ablation was simulated on all sustained episodes. Results: With no fibrosis, sustained AF was achieved in 55.9±32.0% of induction attempts. This percentage was significantly increased to 92.6±15.7% and 93.4±12.8% with diffuse fibrosis and combined dense and diffuse fibrosis, respectively (p<0.0001 for both). PV ablation terminated 75% of episodes induced with no fibrosis, 62% with diffuse fibrosis and 60% with combined dense and diffuse fibrosis. Organized reentry usually formed after ablation with dense scar providing an anchor for reentry in episodes where dense scar is present. Conclusions: Both diffuse and dense fibrosis significantly increases the likelihood for AF induction and maintenance in the computer model with dense fibrosis providing additional anchor points in the left atrium for reentrant circuits.

Surgical treatment of atrial fibrillation: technique of thoracoscopic radiofrequency fragmentation of the left atrium

2019 ◽  
Vol 25 (4) ◽  
pp. 146
Author(s):  
S. A. Vachev ◽  
A. V. Bogachev-Prokof'ev ◽  
A. S. Zotov ◽  
D. A. Elesin ◽  
S. V. Voronin ◽  
...  
Keyword(s):  
Atrial Fibrillation ◽  
Surgical Treatment ◽  
Left Atrium

The Role of Atrial Fibrosis Detected by Delayed - Enhancement MRI in Atrial Fibrillation Ablation

2020 ◽  
Vol 16 (2) ◽  
pp. 135-144 ◽  
Author(s):  
Zsuzsanna Kis ◽  
Astrid Amanda Hendriks ◽  
Taulant Muka ◽  
Wichor M. Bramer ◽  
Istvan Kovacs ◽  
...  
Keyword(s):  
Atrial Fibrillation ◽  
Imaging Modality ◽  
Final Analysis ◽  
Atrial Fibrosis ◽  
Atrial Wall ◽  
Af Ablation ◽  
Left Atrial Wall ◽  
Cmr Imaging

Introduction: Atrial Fibrillation (AF) is associated with remodeling of the atrial tissue, which leads to fibrosis that can contribute to the initiation and maintenance of AF. Delayed- Enhanced Cardiac Magnetic Resonance (DE-CMR) imaging for atrial wall fibrosis detection was used in several studies to guide AF ablation. The aim of present study was to systematically review the literature on the role of atrial fibrosis detected by DE-CMR imaging on AF ablation outcome. Methods: Eight bibliographic electronic databases were searched to identify all published relevant studies until 21st of March, 2016. Search of the scientific literature was performed for studies describing DE-CMR imaging on atrial fibrosis in AF patients underwent Pulmonary Vein Isolation (PVI). Results: Of the 763 citations reviewed for eligibility, 5 articles (enrolling a total of 1040 patients) were included into the final analysis. The overall recurrence of AF ranged from 24.4 - 40.9% with median follow-up of 324 to 540 days after PVI. With less than 5-10% fibrosis in the atrial wall there was a maximum of 10% recurrence of AF after ablation. With more than 35% fibrosis in the atrial wall there was 86% recurrence of AF after ablation. Conclusion: Our analysis suggests that more extensive left atrial wall fibrosis prior ablation predicts the higher arrhythmia recurrence rate after PVI. The DE-CMR imaging modality seems to be a useful method for identifying the ideal candidate for catheter ablation. Our findings encourage wider usage of DE-CMR in distinct AF patients in a pre-ablation setting.

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