Pulmonary vein stenosis after catheter ablation for atrial fibrillation.

Tree randomized trials (PIAF, AFFIRM, and RACE)1-3 recently showed that rate control was not inferior compared to rhythm control for treatment of patients with atrial fibrillation (AF). However, it should be noted that frequent recurrences of AF and adverse effects of drugs decrease the potential benefits of rhythm control, prompting discontinuation of failed drugs in up to 40% of patients.2 In addition, the beneficial effects of rhythm control may be nullified by life-threatening cardiovascular events. Such events may be related not to the rhythm but rather to severe adverse effects of antiarrhythmic drugs, especially if they are used in the long term. In this case, these trials emphasize the need for safer and more effective methods for maintaining sinus rhythm. The quest for better drugs and techniques to achieve this goal will, and should, continue in the future. The relative ineffectiveness of pharmacologic approaches to AF, the risks of antiarrhythmic treatment, and the growing recognition of deleterious AF health effects4 have helped catalyze the development of curative nonpharmacologic approaches to maintenance of sinus rhythm. The management of AF has become more aggressive, with a shift toward nonpharmacologic therapies, including controlled destruction of the substrate generating and maintaining arrhythmia, so-called ablation therapy.5-8 The important new discovery that some episodes of AF are initiated by rapid repetitive firing of atrial myocytes in muscle sleeves located in the pulmonary veins (PVs) has led to the use of catheter-based approaches to isolate these structures electrically, in some cases curing AF.9-11 Mapping and selective ablation of these rapidly firing arrhythmogenic foci have the potential to cure AF. Although theoretically intriguing, the focal ablation approach is extremely arduous and is associated with prolonged procedure and fluoroscopy times, frequent need for second ablation, insufficient atrial ectopy, and development of a major complication—PV stenosis.9 The incidence of this complication is unclear. PV stenosis has been reported in <2% of patients treated but in >20% of PVs treated with ablation. The risk of PV stenosis during long-term follow-up is not known.12 As a typical complication of techniques delivering radiofrequency (RF) energy within PV tissue, PV stenosis can be partly explained by the anatomic and histologic characteristics of the junction between the pulmonary venous vasculature and the left atrium (LA). Myocardial sleeves are always found in the outer layer of PVs, with myocardial cells embed-