Relationship between efficacy of antiarrhythmic drug therapy and structural remodeling in patients with paroxysmal atrial fibrillation

OBJECTIVES: To evaluate whether the response to antiarrhythmic drug therapy in patients with paroxysmal atrial fibrillation affects the development of structural remodeling in the left atrium and ventricle. METHODS: This study included 230 patients (158 men and 72 women, mean age 67 +/- 11 years) in whom antiarrhythmic drug therapy was attempted for > or = 12 months to maintain sinus rhythm (mean follow-up period 45 +/- 27 months). The patients were divided into three groups according to the response to antiarrhythmic drug therapy: group A consisted of 78 patients without recurrence of atrial fibrillation, group B consisted of 87 patients with recurrence of atrial fibrillation and electrical and/or pharmacological cardioversion to restore sinus rhythm, and group C consisted of 65 patients with permanent conversion despite antiarrhythmic drug therapy. RESULTS: In group A, left atrial dimension (LAD), left ventricular end-diastolic dimension (LVDd), and left ventricular ejection fraction (LVEF) did not change after antiarrhythmic drug therapy. In group B, LAD increased significantly after antiarrhythmic drug therapy (from 32.6 +/- 6.4 to 36.0 +/- 6.5 mm, p < 0.01), Whereas either LVDd or LVEF did not change after antiarrhythmic drug therapy. In group C, LAD increased significantly after antiarrhythmic drug therapy (from 37.3 +/- 7.0 to 40.5 +/- 7.9 mm, p < 0.01) and LVEF was significantly reduced after antiarrhythmic drug therapy (from 69.4 +/- 6.2% to 66.5 +/- 8.9%, p < 0.05). LVDd did not change after antiarrhythmic drug therapy. The plasma concentration of human atrial natriuretic peptide during sinus rhythm at the initiation of antiarrhythmic drug therapy in group A (30.5 +/- 26.7 pg/ml) was significantly lower than those in group B (48.0 +/- 49.7 pg/ml) and group C (49.7 +/- 39.5 pg/ml). CONCLUSIONS: The development of structural remodeling in human myocardium can be prevented with antiarrhythmic drug therapy if sinus rhythm is maintained without recurrence of atrial fibrillation in patients with paroxysmal atrial fibrillation.