Abstract 1835: Magnetic Resonance Imaging Detects Chronic Left Atrial Wall Injury Post Ablation of Atrial Fibrillation

Abstract

Radiofrequency (RF) based ablation of atrial fibrillation (AF) through pulmonary vein antrum isolation (PVAI) is a promising treatment for this arrhythmia. Success of the procedure relies in part on the transmural extent of the RF lesions delivered to the left atrium (LA). We describe a novel technique using a 3D MRI to assess sites and extent of LA injury resulting from RF lesions after PVAI. Twelve patients (7 men, mean age 56±11 years) undergoing PVAI for AF were imaged pre and three months post procedure to detect LA scarring with delayed contrast-enhanced MRI using a 3D inversion recovery, navigated, gradient echo pulse sequence. LA injury post procedure was seen in all patients on MRI as areas of bright, signal enhancement, which correlated with the RF energy delivery map during PVAI (figure 1 ). Conclusion: This is the first study to show LA wall injury post PVAI using 3D MRI. These findings may prove important for tracking and monitoring outcomes of AF ablation. Figure 1. Posterior views of the left atrial wall in a patient one day pre (left) and three months post (right) ablation by delayed contrast-enhanced, navigated, 3D MRI. Regions of bright signal show injury resulting from RF ablation.