Abstract 17597: The Effect of Acute Onset Atrial Fibrillation on Left Atrial Thrombogenesis
Introduction: Atrial fibrillation (AF) is associated with increased risk of stroke. While this has partially been attributed to atrial mechanical function, the mechanisms of thrombogenesis in this setting are poorly characterized.
Methods: Twenty patients with AF presenting in sinus rhythm undergoing catheter ablation were studied. Ten patients had atrial pacing at 150beats/min (Pacing group) and ten patients were induced into AF (AF group). Blood samples were obtained from the left atrium (LA) and femoral vein (FV) after transseptal puncture, and 15 minutes after pacing or AF induction. Platelet activation (P-selectin) was measured using flow cytometry. Markers of thrombin generation [thrombin antithrombin (TAT) complex], endothelial dysfunction [Von WilleBrand Factor (vWF)] and platelet-derived inflammation [soluble CD40 ligand (sCD40L)] were measured using enzyme-linked immunosorbent assays.
Results: Platelet activation significantly increased in both groups in the LA compared to FV (p<0.05), and was more marked in the AF group (p<0.01). Thrombin generation was significantly elevated in both groups in the LA compared to FV (p<0.01). There was no significant difference in endothelial dysfunction and platelet-derived inflammation.
Conclusions: Acute onset AF results in increased platelet activation and thrombin generation in the LA compared to the systemic circulation. This prothrombotic activation occurs to a greater extent as a result of AF than rapid atrial rates. These findings implicate a role for rhythm and rate in the milieu for thrombogenesis in atrial arrhythmias.
- © 2010 by American Heart Association, Inc.