Heart, Lung and Circulation

Left Atrial Specific Endothelial Dysfunction and Inflammation in Atrial Fibrillation

      Introduction: Atrial fibrillation (AF) is associated with a prothrombotic state, with thrombus formation frequently occurring within the left atria (LA). We have previously shown that platelet reactivity is increased within the left atria in patients with AF. However little is known about endothelial function and inflammation within the LA.
      Methods: Fifteen AF patients and 16 left sided accessory pathway (REF) undergoing radiofrequency ablation were studied. Following transseptal puncture and prior to the administration of heparin a blood sample (20 mL) was collected from the LA. Markers of endothelial dysfunction (von Willebrand factor [vWF]), and inflammation (intracellular adhesion molecule [ICAM-1] and vascular adhesion molecule [VCAM-1]) were measured using enzyme linked immunosorbent assay.
      Results: AF patients had significantly higher levels of vWF within the LA compared to the LA of REF patients, indicating endothelial dysfunction. ICAM-1 and VCAM-1 were raised in the LA of AF patients when compared to REF (see table).
      Conclusion: AF is associated with left atrial specific endothelial dysfunction and inflammation. This data suggests that LA endothelial dysfunction and inflammation are important contributing factors in the prothrombotic risk associated with AF.
      Tabled 1
      REF left atriaAF left atriaP value
      vWF (mU/mL)571 ± 1321669 ± 223<0.0001
      ICAM-1 (ng/mL)121 ± 76200 ± 980.05
      VACM-1 (ng/mL)386 ± 190499 ± 2460.21