BACKGROUND Approximately 10% to 30% of patients with atrial fibrillation (AF) have no structural heart disease or have a comorbidity such as hypertension. Atrial fibrillation is the most frequent arrhythmia in daily practice that occurs in different situations and its treatment should be based on different presentation scenarios. Strict population-based studies have found that atrial fibrillation is associated with increased morbidity and mortality and poorer quality of life. It is the leading cause of arrhythmia-related hospitalizations, with a major impact on medical costs. Radiofrequency catheter ablation is steadily advancing as an optional therapy to treat atrial fibrillation. Indications for catheter ablation are increasing due to a greater understanding of pathophysiological mechanisms, technological improvements and improved outcomes. The Spanish registry reported that 1 in 10 catheter ablations were indicated for atrial fibrillation. In the United States, atrial fibrillation is the most common condition subjected to catheter ablation in referral centers. How did we get to this point? THE PROBLEM OF ANTIARRHYTHMIC TREATMENT Drug therapy has proven to be ineffective in maintaining sinus rhythm in patients with atrial fibrillation, with relapse rates ranging between 40% and 80%. Class I antiarrhythmic drugs are ideal for patients without structural heart disease or with mild disease due to lower proarrhythmic risk and better tolerance; however, the efficacy of these agents is <40%. In the AFFIRM and RACE studies, the group of patients without structural heart disease was small, and only 30% to 60% were still in sinus rhythm during follow-up. A meta-analysis comparing the effectiveness of antiarrhythmic agents in maintaining sinus rhythm showed that the proportion of patients in sinus r...... middle of paper ......apy for some patients. Circulation 2005;112:1214-31.15. Cappato R, Calkins H, Chen SA, Davies W, Iesaka Y, Kalman J, et al. Prevalence and causes of fatal outcome in catheter ablation of atrial fibrillation. J Am Coll Cardiol 2009;53:1798-803.16. Garcia-Bolao I, Diaz-Infante E, Gallego AM; Working Group of the Spanish Society of Cardiology on Electrophysiology and Arrhythmias. Spanish Catheter Ablation Registry. Seventh official report of the Working Group on Electrophysiology and Arrhythmias of the Spanish Society of Cardiology (2007). Rev Esp Cardiol 2008;61:1287-97.17. Hindricks G. The Multicentre European Radiofrequency Survey (MERFS): complications of radiofrequency catheter ablation of arrhythmias. This was discovered by researchers from the Multicentre European Radiofrequency Survey (MERFS) of the Arrhythmia Working Group of the European Society of Cardiology. Eur Heart J 1993;14:1644-53.