Atrial Fibrillation and the Hypercoagulable State: From Basic Science to Clinical Practice

Atrial fibrillation (AF) is the commonest sustained cardiac rhythm disturbance in clinical practice [1]. Its presence increases mortality by two-fold [2], mostly by increasing the risk of stroke and thromboembolism. The reasons for stroke occurring in AF are multiple and complex, but many strokes related to AF represent embolism of thrombus formed within the left atrium (LA), predominantly within the left atrial appendage (LAA). The elucidation of the pathophysiological mechanisms leading to stroke and thromboembolism in AF have therefore gained much interest. Over 150 years ago, Virchow proposed a triad of abnormalities that predisposes to thrombus formation flow abnormalities, abnormalities of the vessel wall and abnormal blood constituents. The pathophysiology of thromboembolism is AF is multi-factorial but increasing evidence points to the fulfillment of Virchow's triad in this arrhythmia, leading to a prothrombotic or hypercoagulable state in AF. Flow Abnormalities