Study on the spatial distribution pattern of Cx40 gap junctions in the atria of patients with coronary heart disease.

Background: The aim of this study was to evaluate the association between atrial fibrillation and atrial dilation and the spatial distribution pattern of connexin 40 in the atria of patients with coronary heart disease.

Methods: Twenty-six patients with coronary heart disease undergoing cardiac surgery for coronary artery bypass graft were investigated and were divided into three groups according to the left atrial size and rhythm, atrial fibrillation and left atrial dilatation (AF+AD), sinus rhythm and left atrial dilation (SR+AD) and sinus rhythm as control group SR. The spatial distribution patterns of Cx40 were evaluated using confocal laser scanning microscopy assay.

Results: No significant differences were observed in the size and density of Cx40 gap junction in the right atrium among all three groups (p > 0.05). Compared with the control group, the size of Cx40 disk area in termination links and in lateral abutment in left atrium was markedly larger in AF+AD group and SR+AD group than those of the controls (p < 0.01). A comparison of size and density of Cx40 gap junction in the left atrium in the AF+AD group and SR+AD group did not show significant differences.

Conclusions: The present study has shown altered gap junction distribution in coronary heart disease resulting from atrial dilation and atrial fibrillation. A decrease in the size and density of Cx40 gap junction was observed in patients with atrial dilation, which could be an important factor in the initiation and maintenance of atrial fibrillation.