Preoperative atrial histological changes are not associated with postoperative atrial fibrillation.
BACKGROUND
Atrial fibrillation (AF) remains the most common complication of cardiac surgery. Prophylactic therapies have been studied, but their utility has been limited by the inability to accurately identify patients who will develop this complication. Recent studies have suggested that atrial myolysis and lipofuscin pigmentation are associated with post-coronary artery bypass grafting (CABG) AF. We sought to determine whether there is an association between preoperative atrial histology and subsequent post-CABG AF.


METHODS
Samples of right atrial appendage were obtained from 94 patients undergoing CABG. Tissue was formalin fixed and paraffin embedded. Sections 4 mum thick were cut, stained with hematoxylin and eosin, and examined for the following parameters: fibrosis, myolysis, inflammation, nuclear size, pericardial exudates, lipofuscin pigment, arteriolar hypertrophy, contraction banding, mesothelial hyperplasia, and atrial diverticula. Results were graded as absent, mild, moderate, or severe by two independent observers who were blinded to the clinical outcomes. Univariate and multivariate analyses were carried out.


RESULTS
Thirty-six (38%) patients developed AF. No correlation was found between the 10 features assessed, including myolysis and lipofuscin pigmentation, and the development of AF.


CONCLUSION
Simple morphology of right atrial appendages does not predict the development of postoperative AF.