The benefits of catheter ablation in patients with heart failure and atrial fibrillation (AF) were found to be more limited in routine clinical practice compared with those observed in a clinical trial, according to a study published in Heart Rhythm.

Although in the Catheter Ablation for Atrial Fibrillation with Heart Failure (CASTLE-AF;

ClinicalTrials.gov identifier: NCT00643188), catheter ablation in participants with atrial fibrillation (AF) and HF was associated with a 40% reduction in the risk for all-cause mortality and HF hospitalization compared with conventional treatment, the study’s applicability to a wider routine practice population remains largely unknown.


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In this retrospective cohort analysis, 289,831 adult patients with heart failure and AF were identified from a United States administrative database (mean age, 73.2±10.3 years; 47.6% women). In this cohort, patients were treated between January 2008 and August 2018 with catheter ablation (n=7465; mean age, 65.9±10.2 years; 34.5% women) or drug therapy alone (n=282,366; mean age, 73.4±10.2 years; 48.0% women). The cohort was divided according to CASTLE-AF trial eligibility criteria into 3 groups: 7.8% who would have been eligible, 91.0% who would not have met inclusion criteria, and 15.5% who would have met ≥1 exclusion criterion.

The study’s primary outcome was a composite of all-cause mortality and hospitalization for heart failure. Secondary outcomes included all-cause mortality, hospitalization for heart failure, cerebrovascular accident (CVA), and cardiac and all-cause hospitalization. The mean follow-up period was 1.8±1.8 years.

Patients who received ablation vs conventional treatment had a lower risk for the primary outcome  in the entire cohort (hazard ratio [HR], 0.81; 95% CI, 0.76-0.87; P <.001), in the trial-eligible subgroup (HR, 0.82; 95% CI, 0.70-0.96; P =.01), and in the subgroup that would not have met CASTLE-AF inclusion criteria (HR, 0.79; 95% CI, 0.73-0.86; P <.001), but not the group that would have met CASTLE-AF criteria (HR, 0.97; 95% CI, 0.81-1.17; P =.75).

Reductions were observed in the entire cohort for the risk for all-cause mortality (HR, 0.67; 95% CI, 0.62-0.74; P <.001), but not for the risks for heart failure hospitalization (HR, 1.02; 95% CI, 0.94-1.10; P =.67) or CVA (HR, 0.98; 95% CI, 0.82-1.17; P =.81).

The relative risk reduction of ablation vs drug therapy was greater in men, individuals <65 years, and patients without a diagnosis of diabetes mellitus or implanted devices. This relative risk reduction was not affected by the reduced ejection fraction (HFrEF) status.

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Study limitations include possible unmeasured confounding factors, the lack of consistent monitoring for all patients, a lack of information on AF recurrence, and a shorter follow-up than the original trial with substantial drop off after 2 years.

“The benefit associated with ablation appears to be more modest in practice than that reported in the CASTLE-AF trial,” noted the authors. “Future large randomized controlled trials are needed to confirm the benefit of ablation in a broad population of patients with AF and [h]eart failure.”

Reference

Noseworthy PA, Houten HKV, Gersh BJ, et al. Generalizability of the CASTLE-AF trial: catheter ablation for patients with atrial fibrillation and heart failure in routine practice. Heart Rhythm. March 2020. doi:10.1016/j.hrthm.2020.02.030