Magnetic resonance detection of advanced atrial cardiomyopathy increases the risk for atypical atrial flutter occurrence following atrial fibrillation ablation

Abstract

Aims: Recurrence of arrhythmia after catheter ablation of atrial fibrillation (AF) in the form of atypical atrial flutter (AFL) is common among a significant number of patients and often requires redo ablation with limited success rates. Identifying patients at high risk of AFL after AF ablation could aid in patient selection and personalized ablation approach. The study aims to assess the relationship between pre-existing atrial cardiomyopathy and the occurrence of AFL following AF ablation.

Methods and results: We analysed a cohort of 1007 consecutive AF patients who underwent catheter ablation and were included in a prospective registry. Patients who did not have baseline cardiac magnetic resonance imaging and late gadolinium enhancement (LGE-CMR) or did not experience any recurrences were excluded. A total of 166 patients were included gathering 56 patients who underwent re-ablation due to AFL recurrences and 110 patients who underwent re-ablation due to AF recurrences (P = 0.11). A multiparametric assessment of atrial cardiomyopathy was based on basal LGE-CMR, including left atrial (LA) volume, LA sphericity, and global and segmental LA fibrosis using semiautomated post-processing software. Out of the initial cohort of 1007 patients, AFL and AF occurred in 56 and 110 patients, respectively. An age higher than 65 [odds ratio (OR) = 5.6, 95% confidence interval (CI): 2.2-14.4], the number of previous ablations (OR = 3.0, 95% CI: 1.2-7.8), and the management of ablation lines in the index procedure (OR = 2.5, 95% CI: 1.0-6.3) were independently associated with AFL occurrence. Furthermore, several characteristics assessed by LGE-CMR were identified as independent predictors of AFL recurrence after the index ablation for AF, such as enhanced LA sphericity (OR = 1.3, 95% CI: 1.1-1.6), LA global fibrosis (OR = 1.03, 95% CI: 1.01-1.07), and increased fibrosis in the lateral wall (OR = 1.03, 95% CI: 1.01-1.04).

Conclusion: Advanced atrial cardiomyopathy assessed by LGE-CMR, such as increased LA sphericity, global LA fibrosis, and fibrosis in the lateral wall, is independently associated with arrhythmia recurrence in the form of AFL following AF ablation.

Keywords: Atrial cardiomyopathy; Atrial fibrillation; Atrial remodelling; Atypical atrial flutter; Fibrosis.

Graphical Abstract

Advanced atrial cardiomyopathy assessed by LGE-CMR as a predictor of atypical atrial flutter occurrence following atrial fibrillation ablation. Two aspects of atrial cardiomyopathy, specifically increased LA sphericity and LA global fibrosis, are independent predictors of atypical atrial flutter onset compared to atrial fibrillation recurrence following catheter ablation. aOR, adjusted odds ratio; CI, confidence interval; LA, left atrium; LGE-CMR, late gadolinium enhancement cardiac magnetic resonance.

Figure 1

Flow chart of the observational retrospective cohort study. Consecutive patients from 2011 to 2021 were screened and pre-selected based on the presence of baseline LGE-CMR and a redo procedure. Fifty-six patients who developed AFL following AF ablation were included in the study. After a 2:1 randomization, 110 patients were included from the pre-selection list of 215 patients with AF recurrence. AF, atrial fibrillation; AFL, atypical atrial flutter; LGE-CMR, late gadolinium enhancement cardiac magnetic resonance.

Figure 2

Graphical examples of the differential level of atrial cardiomyopathy between patients with onset of atypical atrial flutter following ablation of atrial fibrillation and patients with AF recurrence. Based on post-processing LGE-CMR data, different parameters of morphological and structural left atrial remodelling predict the arrhythmia recurrence in the form of atypical atrial flutter compared with atrial fibrillation. (A) Overlay of the T₁-weighted image with the LGE colour coding based on signal intensity ratios applying thresholds for fibrotic tissue (yellow ≥ 1.2; red > 1.32) using ADAS 3D software (Adas3D Medical, Barcelona, Spain). (B) 3D reconstruction of the left atrium with the automatized regionalization: anterior and posterior wall, floor, septum, lateral wall, and right and left carinas. (C) Assessment of LA volume and LA sphericity using ADAS 3D software (Adas3D Medical, Barcelona, Spain). AF, atrial fibrillation; AFL, atypical atrial flutter; LAA, left atrial appendage; LGE-CMR, late gadolinium enhancement cardiac magnetic resonance; LIPV, left inferior pulmonary vein; LSPV, left superior pulmonary vein; MV, mitral valve; RIPV, right inferior pulmonary vein; RSPV, right superior pulmonary vein.

Figure 3

Graphical representation of the main predictors of atypical atrial flutter occurrence using a univariate logistic regression model. These graphs represent the probability of atrial flutter onset compared with the recurrence of atrial flutter following catheter ablation for atrial fibrillation concerning three main components of atrial cardiomyopathy assessed by LGE-CMR: left atrial sphericity, global fibrosis, and fibrosis among the lateral wall. CI, confidence interval; LA, left atrium; LGE-CMR, late gadolinium enhancement cardiac magnetic resonance; OR, odds ratio.

Figure 4

Receiver operating characteristic curve of left atrial sphericity for prediction of post-atrial fibrillation ablation atypical atrial flutter. AUC, area under the curve; LA, left atrium.