Multimodality Imaging for Atrial Fibrosis Detection in the Era of Precision Medicine

Abstract

In recent years, atrial fibrillation (AF) has increasingly become a focus of attention because it represents the most encountered arrhythmia in clinical practice and a major cause of morbidity and mortality. Issues underlying AF have long been debated; nevertheless, electrical, contractile, and structural remodeling is demonstrated to be the pivotal contributor to arrhythmic substrate. Fibrosis is a hallmark of arrhythmogenic structural remodeling, resulting from an accumulation of fibrillar collagen deposits, as a reparative process to replace degenerating myocardium with concomitant reactive fibrosis, which causes interstitial expansion. Although the precise role of fibrosis in AF initiation and maintenance remains to be fully elucidated, a better definition of its extent and distribution may assist in designing individually tailored ablation approaches and improving procedure outcomes by targeting the fibrotic substrates with an organized strategy employing imaging resources. A deep comprehension of the mechanisms underlying atrial fibrosis could be crucial to setting up improved strategies for preventing AF-promoting structural remodeling. Imaging modalities such as echocardiography, cardiac computed tomography, and cardiac magnetic resonance, combined sometimes with invasive electroanatomical mapping, could provide valuable information for the optimal patients’ management if their use is not limited to cardiac anatomy study but extended to characterize abnormal left atrial substrate. Although pulmonary vein isolation is usually efficacious in treating paroxysmal AF, it is not sufficient for many patients with nonparoxysmal arrhythmias, particularly those with longstanding persistent AF. Noninvasive imaging techniques play a pivotal role in the planning of arrhythmic substrates ablation and show a strong correlation with electro-anatomic mapping, whose novel multipolar mapping catheters allow nowadays a more precise comprehension of atrial substrate. This review aims to explore the impact of the various imaging modalities for the detection of atrial fibrosis and their role in the management of AF.

Assessing the impact of blocking distal coronary sinus-left atrial muscular connection on inducible rate of atrial fibrillation and follow-up recurrence in persistent atrial fibrillation patients with different fibrotic degrees of left atrial: A retrospective study

“…In the present study, we found a significant difference between the patients that successfully blocked the CSD-LA musculature (Group A) and those who did not (Group B) in the acute AF induction rate (53.2% vs. 83.3%, p = 0.013) and atrial arrhythmia recurrences of follow-up (25.5% vs. 50.0%, p = 0.039). These results might add further clinical evidences for the associations of the CS distal musculature with acute AF induction and its role in improving the outcomes of PersAF during follow up, which were coincident with previous studies conducted by Barletta et al and Huang et al ( 6 , 8 ). Among the patients of Group A, the results of ROC curve analysis suggested that under the premise of blocking CSD-LA, LVA of LA below 19% was paralleled with lower acute AF induction (sensitivity and specificity of 92.3 and 90.5%) and LVA of LA below 19.6% accounted for a lower rate of atrial arrhythmia recurrences (sensitivity and specificity of 100 and 65.7%).…”

“…This approach has also presented a similar result in the DECAAF study. Additionally, the Bipolar mapping is a convenient, efficient, and alternative way to quantify the fibrotic area of the LA (6). Besides, the CS Abbreviations: PersAF, Persistent atrial fibrillation; CS, coronary sinus; AFL, atrial flutter; AF, fibrillation; CSD, distal coronary sinus; LA, left atrial; LVA, low voltage area; CPVI, circumferential pulmonary vein isolation; SR, sinus rhythm; PVs, pulmonary veins; PAF, paroxysmal atrial fibrillation; AT, atrial tachycardia; EC, electrical cardioversion; AI, ablation index; TPI, tissue proximity indication.…”

“…This approach has also presented a similar result in the DECAAF study. Additionally, the Bipolar mapping is a convenient, efficient, and alternative way to quantify the fibrotic area of the LA ( 6 ). Besides, the CS musculature can be served as an anatomical substrate for AF and atrial flutter (AFL) ( 7 ).…”

Early Echocardiographic Predictors for Atrial Fibrillation Propensity: The Left Atrium Oracle

“…Two-dimensional transesophageal echocardiography (TOE). LA diameter, area and volume help quantify LA anatomical remodeling, and are used as predictors of AF onset and recurrence [ 19 ]. The LA is also a marker of diastolic dysfunction and increased LA pressures, both associated with the development of AF [ 20 , 21 ].…”

Plasma miR-486-5p Expression Is Upregulated in Atrial Fibrillation Patients with Broader Low-Voltage Areas

“…Nevertheless, AF recurrence after ablation is highly correlated with previous atrial remodeling [5]. Atrial fibrosis can possibly be estimated via an electroanatomic mapping (EAM) system [6], combining electrophysiological data with anatomical information for the construction of 3D endocardial maps [7,8], thereby becoming an essential tool to assess the underlying substrate for the presence of low-voltage areas (LVAs) at the time of the ablation [9]. LVAs have been described both in paroxysmal and persistent AF, hypothesizing that LVAs are not necessarily related to AF duration [10].…”