Abstract 4146910: Impact of Catheter Ablation on Atrial Fibrillation Outcomes in Various Cardiomyopathies: Findings from LGE-MRI Quantified Atrial Fibrosis Analysis

Background: Atrial fibrillation(AF) is the most prevalent arrhythmia in patients with cardiomyopathies(CMs) with and without left ventricular dysfunction. Catheter ablation is widely performed for rhythm control in these patients. Hypothesis: Patients with cardiomyopathies have an increased risk of AF recurrence after catheter ablation. Aims: Characterize the difference in AF recurrence following ablation in Hypertrophic(HCM), ischemic(ICM), and non-ischemic cardiomyopathy(NICM) patients. Characterize the degree and distribution of left atrial(LA) fibrosis among the various CM groups. Methods: Patients undergoing their first catheter ablation for AF were included, assessed for left atrial fibrosis using pre-ablation late-gadolinium enhancement cardiac magnetic imaging(LGE-MRI), and followed for AF recurrence after pulmonary vein isolation, excluding those with prior ablations. Results: A total of 552 patients: 39(7%) HCM, 39(7%) ICM, 115(21%) NICM, and 359(65%) patients without CM were analyzed. Patients with HCM were younger(63±14 years) than other CM subtypes(76.2±8.7 and 68.4±30.8;p<0.001). There was a male predominance noticed across the different groups of cardiomyopathies, except for HCM patients, who had a higher percentage of females(41%vs15%vs22%;p<0.001). Patients with any CM had more LA fibrosis and a higher left atrial volume index(LAVI) compared to patients with no CM(19.1±7.5%vs16.5±6.9%;p=0.01 and 44.9±12.1vs40.8±8.8;p<0.001)respectively. HCM and ICM had higher LA fibrosis compared to NICM(21.3±8.7% and 21.9±9.1% respectively vs17.5±6.3;p=0.01). There was no significant difference in the regionality of fibrosis among the various groups. Multivariate analysis revealed that individuals with HCM had a three-fold increase in the risk of arrhythmia recurrence compared to individuals with no CM(HR=3.07,95%CI:2.06–4.58,p<0.001). Left atrial fibrosis and LAVI were also independently associated with an increased risk of recurrence(HR=1.03,95% CI:1.01–1.06,p=0.01 and HR=1.02,95% CI:1.01–1.03,p=0.01) respectively. Conclusion: HCM had a higher arrhythmia recurrence risk than other CM types in AF patients undergoing catheter ablation, with overall fibrosis and volume predicting recurrence despite similar fibrosis patterns.