Increasing Atrial Base Rate Pacing to Reduce Atrial Fibrillation

Inclusion Criteria: * Sick sinus syndrome patients having dual-chamber pacemaker * Having paroxysmal AF defined as at least 2 episodes of AHR/AMS \>190 b/min lasting \>6 minutes * Having normal atrioventricular conduction Exclusion Criteria: * Other clinical indications for pacing except sick sinus syndrome (bradycardia-tachycardia syndrome) * History of acute coronary syndrome * Significant heart valve disease * Chronic AF before randomization * Overt heart failure * Malignancy * Any reasons for antiarrhythmic medication use * Inability to follow patients every 3 months