In patients with heart failure, atrial fibrillation may exacerbate ventricular dysfunction and symptoms. In this study, catheter ablation was performed to restore sinus rhythm in patients with heart failure and refractory atrial fibrillation. The results show improvement in the left ventricular ejection fraction, symptoms, exercise capacity, and quality of life. Catheter ablation was performed to restore sinus rhythm in patients with heart failure and refractory atrial fibrillation. There was improvement in the ejection fraction, exercise capacity, and quality of life. Congestive heart failure and atrial fibrillation, the two “epidemics” of cardiovascular disease, 1 are major health problems. They often coexist, and the intersection of the two conditions creates a vicious circle, with congestive heart failure promoting the development of atrial fibrillation and vice versa. 2 , 3 In addition, each increases the morbidity and mortality associated with the other. 4 , 5 Among patients with congestive heart failure, maintaining sinus rhythm with the use of antiarrhythmic drugs is challenging, owing to the limited efficacy and potentially deleterious effects of the drugs. 6 – 10 This finding has led to renewed interest in rate control, stimulated by reports . . .