What clinical trials of ablation for atrial fibrillation tell us – and what they do not

Atrial fibrillation (AF) is the most prevalent cardiac arrhythmia in clinical practice. Radiofrequency and cryoballoon catheter ablation are therapeutic options in addition to antiarrhythmic drug therapy for the treatment of AF. Ablation is effective at reducing recurrent atrial arrhythmias and also in the reduction of AF burden. Besides arrhythmia control, improvement in quality of life and clinical outcomes are also desirable goals with AF treatment. Randomized clinical trials have evaluated ablation in several patient populations, including symptomatic patients as first-line or second-line therapy, asymptomatic patients, and patients with heart failure. These trials clarify the durability of ablation in arrhythmia control, clarify quality-of-life improvement, and identify patient populations in whom ablation may be expected to improve clinical outcomes. In this review, we summarize the major clinical trials involving ablation; discuss the strengths, weakness, and clinical implications of these trials; and highlight the knowledge gaps in our current understanding of AF ablation for future clinical studies.