Magnetic Resonance Imaging-Guided Fibrosis Ablation for the Treatment of Atrial Fibrillation

Introduction Success rates of catheter ablation in persistent atrial fibrillation (AF) remain suboptimal. A better and more targeted ablation strategy is urgently needed to optimize outcomes of AF treatment. We sought to assess the safety and efficacy of targeting atrial fibrosis during ablation of persistent AF patients in improving procedural outcomes. Methods The DECAAF II trial (ClinicalTrials. gov identifier number NCT02529319) is a prospective, randomized, multicenter trial of patients with persistent AF. Patients with persistent AF undergoing a first‐time ablation procedure were randomized in a 1:1 fashion to receive conventional pulmonary vein isolation (PVI) ablation (Group 1) or PVI + fibrosis‐guided ablation (Group 2). Left atrial fibrosis and ablation induced scarring were defined by late gadolinium enhancement magnetic resonance imaging at baseline and at 3–12 months postablation, respectively. The primary endpoint is the recurrence of atrial arrhythmia postablation, including atrial fibrillation, atrial flutter, or atrial tachycardia after the 90‐day postablation blanking period. Patients were followed for a period of 12–18 months with a smartphone ECG Device (ECG Check Device, Cardiac Designs Inc.). With an anticipated enrollment of 900 patients, this study has an 80% power to detect a 26% reduction in the hazard ratio of the primary endpoint. Results and Conclusion The DECAAF II trial is the first prospective, randomized, multicenter trial of patients with persistent AF using imaging defined atrial fibrosis as a treatment target. The trial will help define an optimal approach to catheter ablation of persistent AF, further our understanding of influencers of ablation lesion formation, and refine selection criteria for ablation based on atrial myopathy burden.

Section: Resultsmentioning

confidence: 99%

Efficacy of LGE‐MRI‐guided fibrosis ablation versus conventional catheter ablation of atrial fibrillation: The DECAAF II trial: Study design

Marrouche

Greene

Dean

et al. 2021

“…The ALICIA trial has recently demonstrated there is no benefit of an MRI‐guided ablation. This might be due to the ablation targets 33 . In the ALICA trial, the RF applications seemed to be delivered to strong fibrotic areas but not weak fibrotic areas.…”

Section: Discussionmentioning

confidence: 99%

Late‐gadolinium enhancement properties associated with atrial fibrillation rotors in patients with persistent atrial fibrillation

Nakamura

Kiuchi

Fukuzawa

et al. 2021

Background A computational model demonstrated that atrial fibrillation (AF) rotors could be distributed in patchy late‐gadolinium enhancement (LGE) areas and play an important role in AF drivers. However, this was not validated in humans. Objective The purpose of this study was to evaluate the LGE properties of AF rotors in patients with persistent AF. Methods A total of 287 segments in 15 patients with persistent AF (long‐standing persistent AF in 9 patients) that underwent AF ablation were assessed. Non‐passively activated areas (NPAs), where rotational activation (AF rotor) was frequently observed, were detected by the novel real‐time phase mapping (ExTRa Mapping). The properties of the LGE areas were assessed using the LGE heterogeneity and the density which was evaluated by the entropy (LGE‐entropy) and the volume ratio of the enhancement voxel (LGE‐volume ratio), respectively. Results NPAs were found in 61 (21%) of 287 segments and were mostly found around the pulmonary vein antrum. A receiver operating characteristic curve analysis yielded an optimal cutoff value of 5.7% and 10% for the LGE‐entropy and LGE‐volume ratio, respectively. The incidence of NPAs was significantly higher at segments with an LGE‐entropy of >5.7 and LGE‐volume ratio of >10% than at the other segments (38 [30%] of 126 vs. 23 [14%] of 161 segments; p = .001). No NPAs were found at segments with an LGE‐volume ratio of >50% regardless of the LGE‐entropy. Of five patients with AF recurrence, NPAs outside the PV antrum were not ablated in three patients and the remaining NPAs were ablated, but their LGE‐entropy and LGE‐volume ratio were low. Conclusion AF rotors are mostly distributed in relatively weak and much more heterogenous LGE areas.

“…Recently, the ALICIA (the isolation of pulmonary veins with the aid of magnetic resonance imaging) trial demonstrated that an ablation approach targeting cardiac magnetic resonance detected atrial fibrosis plus a PVI is not more effective than a PVI alone in an unselected population undergoing AF ablation with a low fibrosis burden 23 . However, an LGE‐MRI‐based computer simulation model demonstrated that meandering reentrant AF drivers are located at boundary zones between fibrotic and non‐fibrotic tissue characterized by a high entropy where the lower local conduction velocity is documented 21,24 .…”

Section: Discussionmentioning

confidence: 99%

Feasibility of catheter ablation in patients with persistent atrial fibrillation guided by fragmented late‐gadolinium enhancement areas

Kiuchi

Fukuzawa

Takami

et al. 2021

Background A computer simulation model has demonstrated that atrial fibrillation (AF) driver can be attached to heterogeneous fibrosis assessed by late gadolinium enhancement magnetic resonance imaging (LGE‐MRI). However, it has not been well elucidated in patients with persistent AF. The aim of this study was to investigate whether radiofrequency (RF) applications in the fragmented LGE area (FLA) could terminate AF or convert it to atrial tachycardia (AT) and improve the rhythm outcome. Methods A total of 31 consecutive persistent AF patients with FLAs were enrolled (FLA ablation group, mean age: 69 ± 8 years, mean left atrial diameter: 42 ± 6 mm). A favorable response was defined as direct AF termination or AT conversion during RF applications at the FLA. The rhythm outcome was compared between the FLA ablation group and FLA burden‐matched pulmonary vein isolation (PVI) group. Results Favorable responses were found in 15 (48%) of 31 patients in the FLA group (AF termination in seven, AT conversion in eight patients), but not in the PVI group. AF recurrence at 12 months follow‐up was significantly less in the FLA ablation group than in the PVI group (4 [13%] vs. 12 [39%] of 31 patients, log‐rank p = .023). In patients with a favorable response, AT recurred in 1 (7%) of 15 patients, but AF did not. Conclusions FLA ablation could terminate AF or convert it to AT in half of the patients. No AF recurrence was documented in patients with a favorable response.