Background: Colchicine is commonly used early after atrial fibrillation (AF) ablation to reduce inflammation and reduce AF recurrence, but there is limited long-term efficacy data. Objective: To evaluate the effect of low dose colchicine use on long-term AF recurrence after AF ablation. Methods: From 2013 to 2021, all AF ablations performed at a single tertiary care medical center were analyzed for colchicine use, clinical and procedural characteristics, and AF recurrence. The colchicine dose was 0.3-0.6 mg once daily for 30 days. The primary outcome was AF recurrence, defined as AF detection for more than 30 seconds after a three-month blanking period. Propensity score matching (PSM, 1:1 match) was performed using covariates that were significant predictors of AF recurrence in prior studies. The minimum duration of follow-up was 6 months. Kaplan-Meier analysis was conducted to assess time to AF recurrence in the entire cohort and the PSM cohort. Results: The study population consisted of 1568 AF ablations in 1412 patients (67% male, age 65 ± 7 years and mean follow up 34 ± 14 months); 78% of the patients received colchicine. Colchicine use was associated with decreased AF recurrence (HR 0.78, CI 0.63-0.96, p=0.022). After PSM there were 275 patients in each group. AF recurrence was lower with colchicine (HR 0.71, CI 0.53-0.96, p=0.026). Conclusions: Low dose colchicine use was associated with lower long-term AF recurrence after AF ablation. A randomized, placebo-controlled trial is warranted to confirm if low dose colchicine should be used routinely after AF ablation.

Background The benefit of implantable cardioverter defibrillator (ICD) therapy in patients who have heart failure with improved left ventricular ejection fraction (LVEF) to >35% after implantation (HFimpEF) is controversial. Methods Databases (Ovid MEDLINE, EMBASE, Web of Science, and Google Scholar) were queried for studies of ICD patients that reported the association between HFimpEF and arrhythmic events (AEs), defined as the combined incidence of ventricular arrhythmias, appropriate ICD intervention and sudden cardiac death (primary composite endpoint). Results A total of 41 studies and 38,572 patients (11,135 with HFimpEF, 27,437 with persistent EF <35%) were included; mean follow up was 43 months. HFimpEF was associated with decreased AEs (OR 0.39, 95% CI 0.32-0.47; annual rate (AR) 4.1% vs. 8%; P<0.01). Super-responders (EF >50%) had a lower risk of AEs than patients with more modest reverse remodeling (EF>35% and <50%, OR 0.25, 95% CI 0.14-0.46; AR 2.7% vs. 6.2%; P<0.01). HFimpEF patients who had an initial primary prevention indication had a lower risk of AEs (OR 0.43, 95% CI 0.3-0.61; AR 5.1% vs. 10.3%; P<0.01). Among primary prevention patients who had never received appropriate ICD therapy at the time of generator change, HFimpEF was associated with decreased subsequent AEs (OR 0.26, 95% CI 0.12-0.59; AR 1.6% vs. 4.8%; P<0.01). Conclusion HFimpEF is associated with reduced, but not eliminated, risk for AEs in patients with ICDs. The decision for replacing an ICD in lower risk subgroups should incorporate shared decision making based on risks for subsequent AEs and procedural complications.