Atrial Fibrillation Burden and Clinical Outcomes in Heart Failure: The CASTLE-AF Trial

Abstract

Objectives: This subanalysis of the CASTLE-AF (Catheter Ablation vs. Standard Conventional Treatment in Patients With LV Dysfunction and AF) trial aimed to address the association between atrial fibrillation (AF) recurrence, AF burden, and hard clinical outcomes in heart failure (HF) patients with AF.

Background: The CASTLE-AF trial demonstrated the benefit of CA compared to pharmacological treatment in decreasing mortality and CV hospitalizations in patients with AF and HFrEF. However, the impact of AF recurrence and AF burden after ablation on long-term treatment benefit remains unknown.

Methods: The CASTLE-AF protocol randomized 363 patients with coexisting HF and AF in a multicenter prospective controlled fashion to catheter ablation (n = 179) versus pharmacological therapy (n = 184). Two hundred eighty patients were included in this subanalysis (as-treated), 128 of them underwent ablation and 152 received pharmacological treatment. All patients had implanted dual chamber or biventricular implantable defibrillators with activated home monitoring capabilities. The individual AF burden was calculated as the percentage of the atrial arrhythmia time per day.

Results: AF burden at baseline was not predictive of the primary endpoint (p = 0.473) or all-cause mortality (p = 0.446). AF recurrence (defined as any episode >30 s) did not show any relationship with the primary endpoints of mortality and occurrence of HF, irrespective of the treatment arm. An AF burden below 50% after 6 months of catheter ablation, was associated with a significant decrease in primary composite outcome (hazard ratio [HR]: 0.33; 95% confidence interval [CI]: 0.15 to 0.71; p = 0.014) and all-cause mortality (HR: 0.23; 95% CI: 0.07 to 0.71; p = 0.031). The risk of the primary endpoint or mortality was directly related to a low (<50%) or high (≥50%) AF burden at 6 months post-ablation.

Conclusions: AF burden at 6 months was predictive of hard clinical outcomes in HF patients with AF. The first recurrent atrial tachyarrhythmia episode >30 s after ablation was not associated with improvement in mortality and hospitalization for HF. (Catheter Ablation vs. Standard Conventional Treatment in Patients With LV Dysfunction and AF [CASTLE-AF]; NCT00643188).

Keywords: atrial fibrillation; atrial fibrillation burden; heart failure.

Conflict of interest statement

Funding Support and Author Disclosures This study was funded by Biotronik. Dr. Brachmann has received consulting fees from Abbott, St. Jude Medical, Medtronic, Bayer, LivaNova, Pfizer, Boston Scientific, Boehringer Ingelheim, and Biotronik. Dr. Sohns has received modest lecture honoraria and congress sponsoring from Abbott, Biosense Webster, and Medtronic. Dr. Boersma has received consulting fees, paid to his institution, from Medtronic and Boston Scientific. Dr. Merkely has received grant support from Boston Scientific; and has received lecture fees from Medtronic, Biotronik, St. Jude Medical, and Terumo. Dr. Sanders has received grant support from St. Jude Medical, Boston Scientific, Biosense Webster, Biotronik, LivaNova, and Medtronic; has served on advisory boards for St. Jude Medical, Boston Scientific, Biosense Webster, CathRx, Biotronik, LivaNova, and Medtronic; and has received consulting fees from St. Jude Medical, Boston Scientific, and Medtronic. Dr. Bänsch has received consulting fees from Biotronik. Dr. Marrouche has received grant support and consulting fees from Abbott, Wavelet Health, Medtronic, Vytronus, Biosense Webster, Boston Scientific, GE Health Care, and Siemens; has received consulting fees from Preventice; and holds equity in Marrek and Cardiac Design. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose.

Copyright © 2021 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.