Etiology and complications of atrial fibrillation: insights from pathology studies.

Atrial fibrillation (AF) is an arrhythmia associated with a wide variety of cardiac conditions, and it carries a risk of thromboembolism which varies with the underlying disease. The prevalence of AF increases markedly with age, and a review of histopathologic studies reveals that normal aging produces histologic changes in atrial conduction that may lead to the development of atrial arrhythmias. The diverse pathologic causes of AF also result in histologic abnormalities, and an examination of the relation of the etiology of the arrhythmia to pathologic changes suggests a possible reason for the varying risk of thrombus formation. The interaction between the histologic abnormalities and the presence of triggers of AF may also play an important role in the onset and maintenance of this common condition.