Association of Atrial Fibrosis Quantified Using LGE‐MRI with Atrial Appendage Thrombus and Spontaneous Contrast on Transesophageal Echocardiography in Patients with Atrial Fibrillation

Abstract

Introduction Transesophageal echocardiography (TEE) is used to evaluate for left atrial appendage (LAA) thrombi prior to restoration of sinus rhythm in atrial fibrillation (AF). We examined the relationship of atrial fibrosis quantified using late gadolinium enhancement MRI (LGE-MRI) with TEE findings. Methods and Results We included 178 patients with AF, undergoing TEE and LGE-MRI prior to ablation or cardioversion. LGE-MRI and subsequent image processing was used to quantify atrial fibrosis based on signal intensity analysis. The mean CHADS2 score was 1.24±1.08 and CHA2DS2-VASc was 2.08±1.33. The LAA was classified as normal, spontaneous echo contrast (SEC) present or thrombus present. LAA thrombus was found in 12 patients (6.7%) while SEC was identified in 19 patients (10.7%). Patients with thrombus had higher atrial fibrosis compared to patients without thrombus (26.9±17.4% vs 16.7±10.5%; p<0.01). Atrial fibrosis was also higher in patients with SEC (23.3±13.7%) compared to those without SEC (16.7±10.8%; p=0.01). Patients with high atrial fibrosis (>20%) were more likely to have a LAA thrombus (Odds Ratio 4.6; p=0.02) and SEC (Odds ratio 2.6; p=0.06). Multivariate logistic regression showed high fibrosis (Odds Ratio 3.6; p<0.01) and CHADS2≥2 (Odds Ratio 3.5; p<0.01) were significant predictors of TEE abnormalities (LAA thrombus or SEC). The area under the curve for the model including high fibrosis, AF type and CHADS2≥2 or CHA2DS2-VASc≥2 was 0.73 compared to 0.63 and 0.65 for CHADS2 and CHA2DS2-VASc alone. Conclusions Atrial fibrosis is independently associated with appendage thrombus and spontaneous contrast. It provides additional risk stratification not captured by clinical parameters.

Association between left atrial low-voltage area, serum apoptosis, and fibrosis biomarkers and incidence of silent cerebral events after catheter ablation of atrial fibrillation

“…Thrombogenic tendency in patients with AF may be influenced by LA pathologic substrate [17][18][19]. Although LA remodeling may increase the risk of stroke [17,19], its relationship to SCE after CA of AF has not yet been studied.…”

Fusion of Delayed-enhancement MR Imaging and Contrast-enhanced MR Angiography to Visualize Radiofrequency Ablation Scar on the Pulmonary Vein

“…5 Segmentation of the LA wall required the manual tracing of the endocardial border and the LA-PV blood pool in each slice of the DE-MRI volume. Similarly, Bisbal's group reported manual delineation of the epicardial and endocardial borders on axial-plane slices using selfcustomized software (Tissue Characterization Tool Kit) based on MATLAB (The MathWorks, Natick, MA, USA).…”

“…367-372, 2015 ©2015 Japanese Society for Magnetic Resonance in Medicine TECHNICAL NOTE doi:10.2463/mrms.2014-0136 previous studies. [2][3][4][5][7][8][9] We used a 3D inversion recovery, respiration-navigated, ECG-gated, T 1 -TFE sequence in the transverse plane to acquire DE-MRI 15 min after contrast injection. Typical scanning parameters were: TR/TE, 4.7/1.5 ms; voxel size, 1.25 © 1.26 © 2.60 mm (reconstructed to 0.63 © 0.63 © 1.30 mm); flip angle, 15°; inversion time (TI), 280 to 330 ms; SENSE with a reduction factor of 2; and 80 slices.…”

“…[2][3][4] However, the identification of areas of delayed enhancement is difficult in row MR images because of the thin left atrial wall (LA), so previous studies reported the need for specialized software for that identification. 4,5 Unfortunately, even with the use of specialized software, the image quality of 3-dimensional (3D) DE-MRI visualization was insufficient to recognize the location of areas of delayed enhancement due to poor anatomical information.…”

Left Atrial Appendage Exclusion for Atrial Fibrillation

“…85 Atrial tissue changes which accompany AF include cardiomyocyte hypertrophy, interstitial fibrosis, and molecular changes of oxidative stress. 86 The degree of atrial fibrosis as assessed by late gadolinium enhancement on MRI has been associated with the presence of LAA thrombi and spontaneous contrast, 87 as has left atrial dysfunction identified by strain imaging which identifies abnormalities in myocardial deformation. 88,89 Bipolar voltage mapping of the left atrium in AF has correlated the extent of myopathic low voltage electrograms (≤0.5 mV) with reduced LAA emptying velocity.…”