Clinical subtypes of lone atrial fibrillation

AIMS: In the face of increasing evidence of underlying genetic heterogeneity for lone atrial fibrillation (LAF), we undertook a clinical analysis of subjects to identify the phenotypic subsets of this arrhythmia. METHODS AND RESULTS: We evaluated serial patients who presented with LAF between July 5, 2001 and December 19, 2003. Subjects underwent a standardized interview to elicit a detailed medical history, prior therapies, and precipitants of atrial fibrillation. The results of a physical exam, electrocardiogram and echocardiogram were reviewed. One hundred and eighty subjects with a mean age of 45 years (15-67 years) at the time of diagnosis were enrolled. The majority of patients originally presented with paroxysmal fibrillation (94%), and 7.8% progressed to permanent AF. Reported triggers for AF included sleeping (44%), exercise (36%), alcohol use (36%), and eating (34%). Women with LAF had distinct symptoms, triggers for episodic AF, and over one-fourth had an underlying rheumatologic condition. Several subsets of AF including familial AF (39%), exercise-induced AF (32%), and conduction system disease requiring pacemaker implantation (7%), were identified. CONCLUSIONS: Family history, exercise as a trigger of AF, and a history of a pacemaker identified subtypes of LAF.