When exploring predictors of the recurrence of atrial fibrillation (AF) after ablation, it is necessary to understand that risk factors for progression from paroxysmal to chronic AF with treatment other than ablation such as the natural history of the disease or antiarrhythmic drug therapy underlie the predictors of AF recurrence after ablation (Table 1). Among them, the CHADS^₂ score is a predictor of cerebral infarction, and the HATCH score is a predictor of progression from paroxysmal to chronic AF. In addition to these scores, renal failure and valvular heart disease are risk factors for the exacerbation of atherosclerosis, cardiac preload and afterload, and cardiac function. It is considered that paroxysmal AF develops with these coexisting conditions and exacerbates these conditions, resulting in progression from paroxysmal to chronic AF1).