目的观察临床上心律失常常见发生部位及射频消融治疗靶点部位———房室交界区和邻近区域的形态学特点及连接蛋白(Cx)43和40的表达,为心律失常发生机制及可能的有效治疗部位提供形态学依据。方法 10例正常成人心脏,选取房室交界区及其邻近部位,常规石蜡包埋,HE、Masson染色,选定目标部位行Cx43、Cx40免疫组织化学染色,并进行图像及统计学分析。结果峡部、冠状窦口周围和远端、二尖瓣纤维环处及与右房瓣上肌环邻近的中心纤维体等处可见较多过渡细胞束走行,并从不同方向与房室结及结后延伸不同部位相连。过渡细胞组成、排布、心肌纤维走行和相互间的联系有别于普通工作心肌。Cx43、Cx40在过渡细胞束1～4及右房瓣上肌环中分布范围小但集中,而在左房近膜部处的过渡细胞中表达较多;峡部Cx43、Cx40表达较集中。结论房室交界区及其邻近区域存在双(多)径传导的形态学基础,且与目前常用的射频消融治疗心律失常靶点部位具有对应关系。 OBJECTIVE: To observe the morphological features and the expression of connexin (Cx) 43 and 40 in the borderline and atrioventricular junctional areas of common clinical arrhythmias and radiofrequency ablation target sites. It is the possible mechanism of arrhythmia Effective treatment of the site to provide a morphological basis. Methods Normal adult hearts were obtained from 10 normal adults. The atrioventricular junctional area and adjacent areas were selected and paraffin-embedded, HE and Masson staining were performed. Cx43 and Cx40 immunohistochemical staining were performed on the selected sites and the images and statistical analysis were performed. Results There were more transitional bundles in the isthmus, perioral and distal coronary ostia, mitral annulus and central fibroids adjacent to the right atrial valve. After the extension of different parts connected. Transitional cell composition, arrangement, walking and the relationship between myocardial fibers are different from the general work of the myocardium. The distribution of Cx43 and Cx40 in the transitional cell bundles 1 ~ 4 and the right atrial lobe muscular ring was small but concentrated, but more in the transitional cells of the left atrium near the membrane. The isoforms Cx43 and Cx40 were more concentrated. Conclusions There is a morphological basis of dual (multiple) path conduction in the atrioventricular junctional area and its adjacent area, and it has the corresponding relationship with the current commonly used radiofrequency ablation target site of arrhythmia.