Evaluation of Pulmonary Vein Fibrosis Following Cryoballoon Ablation of Atrial Fibrillation: A Semi-Automatic MRI Analysis

Abstract

Current guidelines recommend the use of cardiac magnetic resonance imaging (MRI) for the management of atrial fibrillation (AF). However, the widespread use of cardiac MRI in clinical practice is difficult to achieve. The aim of the present study is to assess whether cardiac MRI can be adopted to identify ablation-induced fibrosis, and its relationship with AF recurrences. Fifty patients undergoing AF cryoballoon ablation were prospectively enrolled. Cardiac MRI was performed before and 30 days after the index ablation. Commercially available software and a specifically designed image processing workflow were used to quantify left atrium (LA) fibroses. Thirty-six patients were finally included in the analysis; twenty-eight were analyzed with the dedicated workflow. Acute electrical isolation was achieved in 98% of the treated pulmonary veins (PVs). After a median follow-up of 16 months, AF recurrences occurred in 12 patients (33%). In both analyses, no differences were found between the subgroups of patients with and without recurrence in the variation of either LA fibrosis or fibrosis at the ostium of the PV, before and after ablation. The ability to predict arrhythmic recurrences evaluated via the ROC curve of the variations in both LA fibrosis (AUC 0.566) and PV fibrosis (AUC 0.600) was low. Cardiac MRI holds the potential to provide clinically significant information on LA disease and AF progression; however, LA fibrosis cannot be easily identified, either by currently available commercial programs or custom tools.

Epicardial Atrial Fat at Cardiac Magnetic Resonance Imaging and AF Recurrence after Transcatheter Ablation

“…The sequences acquired during the exam were: Angio-MRI (non ECG-gated, 4D time resolved with keyhole 4D-TRAK); LGE-MRI (free breathing navigator and ECG gated inversion recovery gradient-echo sequence). The ablation protocol adopted has been previously detailed elsewhere [Ballatore 2023]. Briefly, through venous femoral accesses a diagnostic decapolar electrophysiological catheter was placed in the coronary sinus (CS), subsequently access to the LA was achieved through a patent foramen ovale or by single transseptal puncture and a 28-mm cryoballoon ablation catheter (Arctic Front Advance, Medtronic) and an inner lumen mapping catheter (Achieve, Medtronic) via a steerable 15Fr sheath (FlexCath Advance, Medtronic) were advanced in each pulmonary vein (PV) ostium.…”