Department of Cardiac Surgery, Hospital General Universitario de Alicante, Alicante, Spain.
Ann Thorac Surg. 2010 Jan;89(1):38-43. doi: 10.1016/j.athoracsur.2009.10.008.
Atrial ischemia, and sinus node ischemia in particular, may be involved in the pathogenesis of atrial fibrillation. In this study we compared the sinus node blood capillary content in normal hearts in sinus rhythm and in pathologic hearts with chronic atrial fibrillation and we analyzed the ultrastructural features of such capillaries.
Sinus node biopsy specimens were obtained from 16 patients in chronic atrial fibrillation undergoing open heart surgery. Control sinus node specimens of normal hearts were obtained at autopsy from 7 subjects. Specimens were processed for immunohistochemical, light microscopy and transmission electron microscopy analysis and compared grossly and with morphometric techniques.
The proportion of sinus node tissue corresponding to capillaries, defined as blood vessel density (or BVD), was estimated as 1.06 +/- 1.47% for the atrial fibrillation group versus 2.12 +/- 2.0% for controls (p < 0001). Internal capillary diameter averaged 21.6 microm in the atrial fibrillation group and 24.2 microm in controls (p = 0.175), whereas external diameter averaged 32.2 microm in the atrial fibrillation group and 38.9 microm in controls (p = 0.052). Ultrastructural analysis demonstrated scarce and interrupted myoendocardial bridges and abnormal deposits of elastic fibers under the endothelial basal membrane at the level of precapillary sphincters and metaarterioles of atrial fibrillation specimens.
There is a significant reduction in the amount of capillaries in the sinus node of hearts in chronic atrial fibrillation. Our findings would support a potential association between sinus node tissue ischemia and chronic atrial fibrillation.
心房缺血，特别是窦房结缺血，可能与心房颤动的发病机制有关。本研究比较了窦性心律正常心脏和慢性心房颤动病理性心脏窦房结毛细血管含量，并分析了这些毛细血管的超微结构特征。
从 16 例行心脏直视手术的慢性心房颤动患者中获取窦房结活检标本。从 7 例尸检正常心脏中获取对照窦房结标本。对标本进行免疫组织化学、光镜和透射电镜分析，并进行大体比较和形态计量学分析。
心房颤动组窦房结组织中对应毛细血管的比例（定义为血管密度或 BVD）为 1.06%±1.47%，对照组为 2.12%±2.0%（p<0.0001）。心房颤动组毛细血管内径平均为 21.6μm，对照组为 24.2μm（p=0.175），而心房颤动组毛细血管外径平均为 32.2μm，对照组为 38.9μm（p=0.052）。超微结构分析显示，心房颤动标本的前毛细血管括约肌和metaarterioles 水平内皮基膜下有稀少和中断的肌心桥以及弹性纤维异常沉积。
慢性心房颤动的窦房结毛细血管数量明显减少。我们的发现支持窦房结组织缺血与慢性心房颤动之间存在潜在的关联。
