Use of ADAS software to quantify myocardial fibrosis on Late-Gadolinium Enhancement MR imaging to guide atrial and ventricular ablations

Introduction: MRI is cornerstone in ventricular cardiomyopathy diagnosis but its role in atrial-myopathy is unknown. ADAS MR analysis was suggested to localize `channels` guiding VT ablations and recently suggested to guide atrial arrhythmia ablations as well.

Objective: Describe our experience with LGE-MRI ADAS analysis by comparison to electro-anatomic mapping (EAM) and evaluate its ability to guide ablations.

Methods: ADAS software analysis of LGE-CMRI to quantify and localize myocardial fibrosis. Pre and post-ablation ADAS performed to assess baseline and ablation-induced fibrosis, respectively. ADAS analysis compared to EAM during ablations.

Results: 98 ADAS-assisted ablations done during 2018-2021, including 80/98 atrial and 18/98 VPC/VT ablations. Pre-ablation ADAS on naïve AF patients showed minimal atrial fibrosis in 45/50 cases, confirmed by EAM in 41/45 cases (91%). Post-ablation ADAS performed in 32/80 AF patients including 130 PVs, revealed complete circumferential fibrosis in 60/130, minimal gaps in 39/130, major gaps in 23/130, and no fibrosis in 7/130 PVs. Among 18 re-do atrial ablations, ADAS matched re-do EAM in 12/18 cases (67%). Increased matching found when post-ablation ADAS performed within 4 months compared with > 4 months from ablation (9/12 vs. 3/6). Selecting 5 HCM and 2 rheumatic heart disease (RHD) patients with minimal atrial fibrosis on ADAS for AF ablation, resulted in 12 months arrhythmia-free period in all.

Of 18 VT-related ADAS, 9 patients had ICD/CRTD. Good quality ADAS obtained in 14/18, while ICD artifacts precluded scar analysis in 4. Good ADAS-EAM match found in 7/11 scar-related VT ablations, where ADAS predicted site of successful ablation.

Conclusion: Baseline ADAS in naïve AF cases was reliable. Post-AF ablation ADAS matches re-do ablation EAM better when done early. Pre-AF-ablation ADAS enabled successful selection of challenging HCM and RHD candidates. High-quality ventricular ADAS was obtained in most cases, including some with ICDs, predicting ablation area in some cases.