Assessment Of Atrial Fibrosis Research Articles

Impact of iNAV and dNAV 3D LGE-CMR on the assessment of atrial fibrosis in atrial fibrillation patients

Abstract Background Late gadolinium enhanced (LGE) cardiac magnetic resonance (CMR) imaging serves as a valuable non-invasive tool for visualizing and quantifying left atrial (LA) fibrosis in atrial fibrillation (AF) patients. The extent of pre-procedural LA-LGE, indicative of native atrial fibrosis, has proven to be a predictor of AF recurrence risk following AF ablation. Consequently, assessing the LA fibrotic burden has emerged as a potential guide for personalized patient management. Currently, most centers engaged in LA-LGE image acquisition apply a scan protocol based on a diaphragmatic navigator-gated 3D image strategy (dNAV). Recently introduced image navigated (iNAV) 3D LGE strategies are proposed to outperform the dNAV strategy. This advancement involves the dynamic tracking of the heart's respiratory position with an image reconstruction algorithm, yielding motion-compensated images in significantly reduced and more consistent scan durations. We performed an evaluation of the novel image navigated (iNAV) 3D LGE-CMR imaging strategy in comparison to the conventional diaphragm navigated (dNAV) 3D LGE-CMR strategy. Methods In twenty-six consecutive AF patients, both imaging techniques (i.e. iNAV and dNAV) were performed subsequently, with equivalent spatial resolution and timing in the cardiac cycle. Patients were randomized in the acquisition order of iNAV and dNAV. LA fibrosis was quantified (percentage of atrial fibrosis using image intensity ratio threshold 1.2) and overlap in atrial fibrosis areas was tested between the two methods. Results Acquisition time of iNAV was significantly lower compared to dNAV (5±1 minutes vs. 12±4 minutes, p<0.001, respectively). There was a significant correlation between the iNAV and dNAV LA fibrotic burden (r=0.69, p<0.001). LA fibrosis scores were lower for iNAV compared to dNAV (12±8% vs. 20±12%, p<0.001, respectively). Spatial correspondence between the atrial fibrosis maps was modest (Dice similarity coefficient 0.43±0.15). Notably, 13/23 (56%) patients underwent a shift in their UTAH fibrosis stage classification, depending on the chosen imaging strategy. Conclusion iNAV acquisition was more than twice as fast as dNAV, and iNAV resulted in a lower atrial fibrosis score as compared to dNAV. More than half of the patients were reclassified into a different UTAH fibrosis stage depending on the employed imaging strategy. This underscores the critical importance of recognizing that the choice of imaging strategy significantly impacts the categorization of patients into their respective fibrosis stages. This distinction carries potential clinical implications when evaluating the utility of UTAH fibrosis stages in the context of AF management and therapeutic decision-making, as patients in lower fibrosis stages are generally regarded as more suitable candidates for ablation, while those categorized in higher fibrosis stages face an increased risk of arrhythmia recurrence following PVI.Figure 1Figure 2

Assessment of Atrial Fibrosis and Its Implications in Atrial Fibrillation and Stroke

Assessment of Atrial Fibrosis and Its Implications in Atrial Fibrillation and Stroke

Searching for the Key to Foreseeing Left Atrial Fibrosis in Atrial Fibrillation: Could This Be Simple and Reliable with MRI?

Searching for the Key to Foreseeing Left Atrial Fibrosis in Atrial Fibrillation: Could This Be Simple and Reliable with MRI?

Atrial fibrillation beyond the arrhythmia: hypercoagulability, adipose tissue, and fibrotic remodelling.

![Graphic][1] Atrial fibrillation is the most common sustained arrhythmia, and its treatment continues to be a challenge. Its managment has recently been reviewed extensively in the 2016 ESC Guidelines on Atrial Fibrillation.1 Current concepts focus on the atrial substrate and triggers from the pulmonary veins as its primary mechanisms. Remodelling of artrial tissue appears to provide the substrate upon which the atrial arrhythmia can develop. In their review article ‘ Magnetic resonance imaging of atrial fibrosis: redefining atrial fibrillation to a syndrome ’,2 Pim Gal and Nassir F. Marrouche from the University of Utah School of Medicine in Salt Lake City, USA remind us that delayed enhancement-magnetic resonamce imaging (DE-MRI) has recently been introduced in the diagnosis and treatment of atrial fibrillation for the assessment of atrial fibrosis, which is considered the hallmark of the arrhythmogenic substrate in atrial fibrillation. Atrial fibrosis is an independent predictor of arrhythmia recurrences. Post-ablation DE-MRI allows for the assessment of the total scar burden, the degree of complete encirclement of pulmonary veins, and the assessment of residual fibrosis, all strong predictors of arrhythmia recurrences post-ablation. Current pathophysiological perspectives for atrial fibrillation are heavily based on the adage ‘AF begets AF’. Potentially, atrial fibrosis as such is a disease process that triggers the initiation and maintenance of atrial fibrillation While anticoagulation with vitamin K antagonists and currently mostly with novel oral anticoagulants (NOACs) prevents the most important complication of atrial fibrillation,3,4 the arrhythmia itself is managed either with drugs or with catheter ablation. Indeed, catheter ablation has become an effective treatment of paroxysmal atrial fibrillation;5 however, its use in patients with persistant atrial fibrillation is less well established. In a second clinical review entitled ‘ Catheter ablation in patients with persistent atrial fibrillation ’, Paulus Kirchhof … [1]: /embed/inline-graphic-1.gif

Magnetic resonance imaging of atrial fibrosis: redefining atrial fibrillation to a syndrome.

Atrial fibrillation (AF) is the most common sustained arrhythmia and its treatment continues to be a challenge. Recently, delayed enhancement (DE)-MRI was introduced in the diagnosis and treatment of AF by the assessment of atrial fibrosis, which is considered the hallmark of the arrhythmogenic substrate in AF. Atrial fibrosis was reported to be an independent predictor of arrhythmia recurrences. Post-ablation DE-MRI allows for assessment of the total scar burden, complete encirclement of pulmonary veins, and the assessment of residual fibrosis, which were all reported to be strong predictors of arrhythmia recurrences post-ablation. Current pathophysiological perspectives for AF are heavily based on the adagium AF begets AF. However, several recent observations, such as atrial fibrosis being present in non-AF patients, do introduce a new pathophysiological perspective for AF. Potentially, atrial fibrosis is a disease process that triggers the initiation and maintenance of the syndrome AF.

Atrial fibrillation and heart failure

Atrial fibrillation and heart failure are two of the most prevalent cardiovascular disease conditions. They often coexist and lead to significant morbidity and mortality. Adequate management strategies for this dual epidemic continue to be the subject of many research studies. Recent clinical trials suggest that a rhythm control strategy for atrial fibrillation does not offer a survival advantage over rate control in heart failure patients with reduced systolic function. Rhythm control in these trials was achieved using antiarrhythmic drugs, with evidence of increased mortality associated with certain agents. Catheter ablation is a more effective and increasingly used approach to maintain sinus rhythm in atrial fibrillation patients, with promising results in the heart failure population. Late-gadolinium-enhancement cardiac MRI (LGE-MRI) assessment of atrial fibrosis helps in selecting the better candidates for atrial fibrillation ablation. AV nodal ablation and bi-ventricular pacing remains another viable option. Atrial fibrillation patients with heart failure and preserved systolic function are another group in whom maintenance of sinus rhythm is thought to be advantageous. Patients with atrial fibrillation and heart failure are a heterogeneous group and require a personalized treatment approach. Catheter ablation to restore and maintain sinus rhythm is a modality that promises to be advantageous beyond rate control.