Magnetic resonance imaging guided cryoballoon ablation for left atrial substrate modification in patients with atrial fibrillation.

Background Cryoballoon ablation (CBA) for pulmonary vein isolation (PVI) is an established modality for the treatment of atrial fibrillation (AF). We report feasibility of left atrial (LA) substrate modification in addition to PVI both using the cryoballoon. Methods LA substrates and CBA-induced scar were assessed at baseline and 3 months after ablation using late gadolinium enhancement magnetic resonance imaging (LGE-MRI). Common periprocedural data including postablation LGE-MRI for evaluation of esophageal thermal injury, and CBA-associated complications were collected. Freedom from AF recurrence at 12 months was assessed using Holter and 30-day rhythm monitors. Results In 26 patients (64 +/- 11 years, 69% male; 27% persistent AF, CHADSVASC score: 2.3 +/- 1.5; left ventricular ejection fraction: 56 +/- 10%, oral anticoagulation with warfarin/direct oral anticoagulants: n = 11/15), referred for first-time AF ablation, CBA of the pulmonary veins and extrapulmonary LA substrates was performed (median: 12 [interquartile range {IQR}: 7-14] freezes over 1675 seconds [IQR: 1168-2160]). On LGE-MRI, significant postablation cryoballoon-induced LA scar (median: 19.4% [IQR: 13.4-24.7] in comparison to baseline preablation LA-LGE (median: 10.6% [IQR 3.1-13.1]; P = .01) was found. Freedom from AF recurrence at 12 months was 74.5% with median time-to-recurrence of 242 days (IQR: 172-298). In 15 of 26 (58%) patients, esophageal enhancement on the postablation MRI was present with full recovery after 3 months. No major periprocedural complications were observed. Conclusion LA substrate modification in addition to PVI using LGE-MRI-guided CBA is feasible but still experimental. The efficacy and safety have to be investigated in a prospective randomized trial.