Abstract Body (Do not enter title and authors here): 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.