Catheter ablation of atrial fibrillation (AF) in patients with heart failure associated with a reduced EF (HFrEF) was associated with a significantly lower rate of a composite endpoint of death from any cause or hospitalization for worsening heart failure (HF) than medical therapy in the CASTLE-AF trial. In patients with HF and also with a preserved EF (HFpEF), AF is known to be associated with increased mortality. Although the particular benefit in patients with an EF >35% may suggest the need for prospective randomized control trial data in patients with HF to assess the role of ablation as a first-line therapy as Sessions AJ, et al. stated, we believe at present that 1) whether there is structural heart disease detected by cardiac images and 2) whether the left atrial voltage is generally low, should be assessed “before ablation” in each patient with HF to achieve a successful ablation.