Department of Genetics and Morphology, Brasilia's University, Campus Asa Norte, Cep: 70910-900, Brasilia, Brazil.
Institute of Genetic Medicine, Newcastle University, Newcastle-upon-Tyne, UK.
Clin Anat. 2023 Jul;36(5):787-794. doi: 10.1002/ca.24022. Epub 2023 Apr 1.
Longitudinal dissociation of the aggregated specialized cardiomyocytes within the non-branching portion of atrioventricular conduction axis has proved a controversial topic for both morphologists and electrophysiologists. We have now used morphological methods, including three-dimensional assessment, to revisit, in human, canine, and bovine hearts, the presence or absence of interconnections between the aggregated cardiomyocytes making up the non-branching bundle. We analyzed three datasets from human and canine hearts, and two from bovine hearts, using longitudinal and orthogonal serial histological sections. In addition, we assessed three hearts using translucent India ink injected specimens, permitting assessment of the three-dimensional arrangement of the cardiomyocytes. Using the longitudinal sections, we found numerous oblique interconnections between the groups of specialized cardiomyocytes. When assessing orthogonal sections, we noted marked variation in the grouping of the cardiomyocytes. We interpreted this finding as evidence of bifurcation and convergence of the groups seen in the longitudinal sections. The three-dimensional assessment of the bovine material confirmed the presence of the numerous interconnections. The presence of multiple connections between the cardiomyocytes in the non-branching bundle rules out the potential for longitudinal dissociation.
房室传导轴非分支部分聚集的特化心肌细胞的纵向分离，对于形态学家和电生理学家来说，一直是一个有争议的话题。我们现在使用形态学方法，包括三维评估，重新研究了在人心、犬心和牛心中，构成非分支束的聚集心肌细胞之间是否存在连接。我们使用纵向和正交的连续组织学切片分析了来自人心和犬心的三个数据集，以及来自牛心的两个数据集。此外，我们使用半透明的印度墨水注射标本评估了三个心脏，允许评估心肌细胞的三维排列。使用纵向切片，我们发现了许多专门的心肌细胞群之间的斜向连接。在评估正交切片时，我们注意到心肌细胞的分组有明显的变化。我们将这一发现解释为纵向切片中所见的细胞群分叉和汇聚的证据。牛材料的三维评估证实了存在许多连接。非分支束中的心肌细胞之间存在多个连接，排除了纵向分离的可能性。
