A comprehensive multi‐index cardiac magnetic resonance‐guided assessment of atrial fibrillation substrate prior to ablation: Prediction of long‐term outcomes

Abstract

Introduction Multiple cardiac magnetic resonance (CMR)‐derived indices of atrial fibrillation (AF) substrate have been shown in isolation to predict long‐term outcome following catheter ablation. Left atrial (LA) fibrosis, LA volume, LA ejection fraction (EF), left ventricular ejection fraction (LVEF), LA shape (sphericity) and pulmonary vein anatomy have all been shown to correlate with late AF recurrence. This study aimed to validate and assess the relative contribution of multiple indices in a long‐term single‐center study. Methods and Results Eighty‐nine patients (53% paroxysmal AF, 73% male) underwent comprehensive CMR study before first‐time AF ablation (median follow‐up 726 days [IQR: 418‐1010 days]). The 3D late gadolinium‐enhanced acquisition (1.5T, 1.3 × 1.3 × 2 mm) was quantified for fibrosis; LA volume and sphericity were assessed on manual segmentation at atrial diastole; LAEF and LVEF were quantified on multislice cine imaging. AF recurred in 43 patients (48%) overall (31 at 1 year). In the recurrence group, LA fibrosis was higher (42% vs 29%; hazard ratio [HR]: 1.032; P = .002), left atrial ejection fraction (LAEF) lower (25% vs 34%; HR: 0.063; P = .016) and LVEF lower (57% vs 63%; HR: 0.011; P = .008). LA volume (135 vs 124 mL) and sphericity (0.819 vs 0.822) were similar. Multivariate Cox regression analysis was adjusted for age and sex (Model 1), additionally AF type (Model 2) and combined (Model 3). In Models 1 and 2, LA fibrosis, LAEF, and LVEF were independently associated with outcome, but only LA fibrosis was independent in Model 3 (HR: 1.021; P = .022). Conclusions LAEF, LVEF, and LA fibrosis differed significantly in the AF recurrence cohort. However, on combined multivariate analysis only LA fibrosis remained independently associated with outcome.

Identifying locations of re-entrant drivers from patient-specific distribution of fibrosis in the left atrium

“…Two persistent AF (PsAF) and four paroxysmal AF (PAF) patients (see Table 1) were imaged under ethical approval and following written informed consent as a part of the study by Chubb et al [26]. All imaging was performed on a 1.5T Phillips MRI scanner and included a LGE MRI sequence: a 3D inversion recovery spoiled gradient echo, acquired 20-30 min after the administration of the extra-cellular gadolinium-based contrast agent Gadovist (Bayer Healthcare Pharmaceuticals).…”

“…These images were acquired using cardiac and respiratory gating, with a spatial resolution of 1.3 x 1.3 x 4 mm 3 . Further information about the used LGE sequence can be found in [26].…”

Effect of family history of atrial fibrillation on recurrence after atrial fibrillation ablation: A report from the Chinese Atrial Fibrillation Registry Study

“…Some rare titin‐truncating variants were found to be associated with atrial fibrosis in the animal models and familial and early‐onset lone AF 29 . Therefore, high risk of AT recurrence is biologically explainable in this genetic background 30 . When age‐related atrial fibrosis developed, 31 effect of genetic background will be diluted and it is not surprise that FAF is no longer a risk factor for AT recurrence in older patients.…”

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

“…In a recent multivariate analysis comparing the impact of different CMR-derived remodelling parameters (including LA volume, sphericity index, LA ejection fraction and fibrosis degree) on CA outcomes, only LA fibrosis emerged as a predictor of late AF recurrences (a median follow up of nearly seven years) [28]. On the other hand, LA volume and fibrosis do not always correlate, emphasizing the idea that a normally-sized LA could be extensively fibrotic [29,30].…”