COR LOE Recommendation IIb B-R AF catheter ablation may be reasonable in selected patients with symptomatic AF and HF with reduced left ventricular (LV) ejection fraction (HFrEF) to potentially lower mortality rate and reduce hospitalization for HF.S6.3.4-1,S6.3.4-2 NEW: New evidence, including data on improved mortality rate, has been published for AF catheter ablation compared with medical therapy in patients with HF. Recommendation-Specific Supportive Text (New) 1. In an RCT (CASTLE-AF [Catheter Ablation vs. Standard Conventional Treatment in Patients With LV Dysfunction and AF]), selected patients with HFrEF with paroxysmal or persistent AF and an implanted cardioverter-defibrillator or cardiac resynchronization therapy defibrillator device who did not respond to or could not take antiarrhyth- mic drugs were randomized to receive AF catheter ablation versus medical therapy (rate or rhythm control) in addition to guideline-directed manage- ment and therapy for HFrEF.S6.3.4-1 Patients in the AF catheter ablation group had significantly reduced overall mortality rate, reduced rate of hospitaliza- tion for worsening HF, and improved LV ejection fraction as compared with the medical therapy group, and according to device interrogation, more patients in the AF catheter ablation group were in sinus rhythm. An additional RCT in a population of patients with persistent AF, HFrEF, and an implanted cardioverter-defibrillator or cardiac resynchroniza- tion therapy defibrillator device demonstrated that AF catheter ablation was superior to amiodarone for maintenance of sinus rhythm, with second- ary endpoint analyses suggesting a lower rate of unplanned hospitalization and death.S6.3.4-2 Both studies have limitations, including relatively small and highly selected patient populations. Further, larger studies are needed to validate these findings. 