Mechanism of Atrial Fibrillation

Joung, Boyoung

Abstract

Atrial fibrillation (AF) remains the most common adult rhythm disorder, and it associated with a substantial rate of morbidity and economic burden. AF involves a wide spectrum of arrhythmias from lone AF to paroxysmal to chronic AF. It is likely that AF comprises a spectrum of disease with no single mechanism adequate enough to comprehensively explain AF and its variability. Mechanism of fibrillation is explained by multiple wavelets and focal activation theories. Electrical, contractile and mechanical remodeling is involved in AF progression. Atrial remodeling may also increase in atrial fibrosis which can slow conduction velocity and can shorten the refractory period in atria ith long-standing AF. Mechanical remodeling manifests as decreased atrial contractility and increased atrial compliance which leads to a stretch of the atrial myocardium. Abnormal intracellular calcium dynamics is observed in AF. Modulating factors such as genetic factors, age, obesity, sleep apnea, inflammation, autonomic factors and atrial and pulmonary vein stretch only partially account for the increase in AF. It is still unclear whether initiation of AF activates direct inflammatory effects or whether the presence of a pre-existing systemic inflammatory state promotes further persistence of AF. Although significant progress in understanding the mechanism of this arrhythmia has been accomplished, the pathophysiology of AF is complex and likely has many possible mechanisms which may be interrelated.