99 Outcomes of catheter ablation for ventricular arrhythmias in cardiac amyloidosis: a retrospective study

Introduction Patients with cardiac amyloidosis (CA) have an increased risk of developing ventricular arrhythmias (VA) but there remains limited evidence supporting the role of catheter ablation in this cohort. Methods An electronic database that uses natural language processing for data retrieval was used to identify all patients suspected of having CA who underwent catheter ablation for VA at our institution between January 2010 and December 2023. Patients who did not meet the diagnosis of CA and had a negative workup for CA who underwent catheter ablation for ventricular tachycardia (VT) or premature ventricular contractions (PVCs) were used to form a control group matched for age and left ventricular ejection fraction. Results 11 controls and 11 CA patients were identified, including 8 with wild-type transthyretin (TTR)-CA, 2 with hereditary TTR-CA, and 1 with light chain (AL)-CA. Comparing the two groups at baseline (table 1), the mean age at index ablation was 67.8 ± 6.7 and 70.6 ± 6.3 years (p=0.32) and the proportion of males was 100% and 90.9% respectively. A significant majority in the CA group had chronic kidney disease (90.9%). Both groups had a high proportion of atrial fibrillation/flutter (72.7% vs. 100%, p=0.21) as well as a similar distribution of VT/PVCs at presentation (54.5%/45.5% vs. 45.5%/54.5%, p=0.665), use of antiarrhythmics (72.7% vs. 54.5%, p=0.59) and left ventricular ejection fraction (42.6% ± 13.8 vs. 42.6 ± 14.0, p=0.99). Before index ablation mean VA burden was 20.5% ± 15.3 vs. 28.8% ± 13.3 (p=0.266, table 2). Intraprocedural ablation time (61.3 ± 56.1 vs. 110.9 ± 52.8 mins, p=0.073, table 2) and total energy delivery time (1139.6 ± 1674.3 vs. 581.6 ± 527.3 secs, p=0.85, table 2) was comparable in the two groups. No major complications occurred following ablation in either the CA or control group (table 2). 4 patients (36.4%) in the CA group had a recurrence of the same arrhythmia compared to 6 (54.5%) in the control cohort (table 2). Postindex ablation mean VA burden was 4.8% ± 8.0 vs. 12.1% ± 17.1 (p=0.220). Mean follow-up time was 4.4 ± 3.1 and 4.7 ± 2.9 years (p=0.82) and there was no significant difference in the time from index ablation to recurrence between the CA and control group (2.61 ± 3.0 vs. 2.34 ± 2.90 years, p=0.496, Fig 1). However, in the CA group, time to recurrence was significantly shorter in patients with multiple types of VT or PVCs 433.2 ± 672.2 days vs. 1575.2 ± 1278.9 days (p=0.044, Fig 2) in patients with a single type of VT or PVC. Comparing time to recurrence in CA patients with a single type of VT or PVCs with their counterparts in the control cohort trended towards a longer time to recurrence 1575.2 ± 1278.9 vs. 722.6 ± 998.3 days (p=0.095, Fig 2). Conclusions Catheter ablation appears to be safe and effective for VT and PVCs in patients with CA. CA patients with a single type of VT or PVC may respond more favourably compared to their counterparts with multiple types. Conflict of Interest None