Durable lesion formation while avoiding esophageal injury during ablation of atrial fibrillation: Lessons learned from late gadolinium MR imaging

Introduction: Adequate catheter/atrial tissue contact is critical for lesion formation during radiofrequency (RF) ablation of atrial fibrillation (AF). Late gadolinium enhancement magnetic resonance imaging (LGE-MRI) is a unique tool for the evaluation of lesion formation and detection of acute esophageal injury. Methods: LGE-MRIs were obtained prior, within 24 hours of, and at 115 +/- 62 days after first AF ablation in 36 patients. The Visitag module of CARTO3 was used to collect contact force (CF) and duration from a CF sensing ablation catheter for each registered ablation point. The minimum CF resulting in permanent lesions was determined. Esophageal enhancement detected by acute LGE-MRI was classified as mild, moderate, and severe. The CF resulting in esophageal enhancement was determined. Results: A total of 4,642 registered ablation tags at 50 W power were analyzed. The mean RF duration (5.9 +/- 3.7 vs. 5.6 +/- 3.2 seconds, P < 0.05), CF (11.5 +/- 5.6 vs. 10.9 +/- 5.4 g, P < 0.001), and force time integral (FTI) (67.3 +/- 54.5 vs. 62.2 +/- 52.7 gs, P<0.01) were significantly higher between ablation tagswith and without associated LGE-MRI detected scar. The mean CF(15.7 +/- 6.1 vs. 12.6 +/- 5.9 g, P < 0.05, n = 17 patients) in areas of esophageal enhancement was greater than areas without. Conclusion: Left atrial short duration ablation lesions with a CF greater than 12 g are more likely to be associated with permanent lesion formation. Ablating on top of the esophagus, CF less than 15 g would help minimize esophageal wall injury.