Frequency of symptomatic atrial fibrillation in patients enrolled in the Atrial Fibrillation Follow-up Investigation of Rhythm Management (AFFIRM) study

Introduction: The frequency of symptomatic paroxysmal atrial fibrillation (AF) may identify subsets with different characteristics. Because the approach to AF now is so varied, ranging from drug therapy to surgery and catheter ablation, the frequency of AF may have important therapeutic implications if the frequency identifies subsets with distinguishing features. Methods and Results: The Atrial Fibrillation Follow-up Investigation of Rhythm Management (AFFIRM) Study is evaluating patients with AF who are at high risk for stroke. We evaluated the clinical characteristics of the patients in the AFFIRM Study in an attempt to identify features that might distinguish patients with infrequent and frequent AF occurrences. Patients were divided into five groups, based upon the historic frequency of occurrence of AF at the time the patients were enrolled in the study. Although statistically significant differences were present among the groups, no important differences were noted in clinical or echocardiographic characteristics that could differentiate patients with frequent episodes of AF from other patients in the AFFIRM population. Conclusion: In a large population of patients with AF at high risk for stroke, individual historic and echocardiographic characteristics failed to distinguish patients based on the frequency of AF. Those with frequent and infrequent AF were similar. Although AF frequency has been suggested as a marker of a focal etiology in young populations with little overt heart disease, it does not seem to be a distinguishing characteristic in older populations at high risk for stroke.