The morphologic study of coronary sinus orifice and its peripheral myocardium / 西安交通大学学报(医学版)

ABSTRACT

Objective To observe the cellular morphologic features of coronary sinus orifice(CSO) and its peripheral myocardium and discuss its functional significance in radiofrequency ablation atrial reentrant arrhythmias and AVNRT. Methods A total of 7 out of 15 cases were observed by means of autopsy, and serial sections of 7 cases of adult hearts in sagittal plane were stained with HE and Mallory staining. The cellular features of different muscular fibers and their arrangement were observed under light microscope; one case was studied under electron microscope. Results CSO and the majority of coronary sinus were encompassed by atrial myocardium; CSO fibers toward posterior was connected with extension of terminal crest (CT); and supravalvular muscular ring of right atrium(RAMR) and that toward anterior was connected with AVN. P cells were seen in superior-anterior and inferior-anterior wall of CSO. A lot of T cells were discovered on the inferior wall of CSO. Purkinje cells were mainly found in the superior wall of CSO. The muscular fibers from CSO to AVN were composed of T cells and dissected into two parts the first one was called right atrial nodular bundle and the second one posterior node extension which was identical with the ablation target of slow pathway. In addition, lots of nerve fibers were seen in myocardium of CSO adjacency particularly in the tissue of the posterior wall of CSO. Conclusion Myocardium of CSO adjacency may belong to slow pathway of DAVNP. The myocardium of CSO adjacency participates in the formation of circular pathway in atrial reentrant arrhythmias and AVNRT. It is possible that CSO is an important latent pacing maker.