Knowledge of the histologic constituency of the sinoatrial (SA) node is based on small studies with unevenly distributed ages and subjective assessments of nodal composition, leading to difficulties in interpreting what constitutes true pathology of the SA node. SA nodes from two-hundred normal hearts (10 male and 10 female from each of the first 10 decades of life) were digitally analyzed to assess their histologic composition. Both nodal area and nodal fat content (≥5%) showed a quadratic relationship with age, peaking in the fifth to eighth decades of life. Increased fat content was also more prevalent with increased BMI (≥25 kg/m²). No differences between sexes were observed. Mean nodal collagen ranged from 7.1% to 50.3%, without a statistically significant differences by age or body mass index (BMI). The data suggests that the designation of pathologic fibrosis should be reserved for SA nodes with >50% collagen content. These findings expand and refine our understanding of the anatomy of the SA node.

对窦房 (SA) 结组织学选区的了解是基于年龄分布不均的小型研究和对结节组成的主观评估，导致难以解释什么构成了 SA 结的真正病理。对来自 200 颗正常心脏（生命的前 10 年中，每人 10 名男性和 10 名女性）的 SA 节点进行数字分析以评估它们的组织学组成。结节面积和结节脂肪含量 ( ≥ 5%) 均与年龄呈二次方关系，在 50 岁至 80 岁达到峰值。随着 BMI 的增加（≥25 kg/m ²）。没有观察到性别之间的差异。平均结节胶原蛋白范围为 7.1% 至 50.3%，年龄或体重指数 (BMI) 无统计学显着差异。数据表明，病理性纤维化的名称应保留用于胶原含量 >50% 的 SA 节点。这些发现扩展和完善了我们对 SA 结解剖结构的理解。