Abstract 2472: Decrease in Morbidity of Clinical Procedures Through Accurate Localization of the Human AV Node and Distal (His) AV Bundle With a New Physiologic Anatomic Protocol
INTRODUCTION: Schematics showing the so-called human AV node (AVN) and posterior nodal inputs inferior to the coronary sinus os (CSO) are being used as guides for ablation of AVN reentrant tachycardia (AVNRT). Yet, CSO is in the posterior-AV junction region (AVJR) and AVN is in the anterior-AVJR of the dog heart as also validated via electrical criteria. Here, a new physiologic anatomic protocol is applied to the human heart.
METHODS: The heart (8) is placed endocardium down on paper towel (to flatten), fixed with Karnovsky solution and rinsed with 5% sucrose buffer, as needed (no water rinses). Gross structures are noted: medial atrial wall (MAW), atrial septum (AKA, fossa ovalis, FO), medial leaflet (ML), CSO, inferior vena cava antrum, muscular (VS-mus) and membranous ventricular septum (VS-mem) inserting into the crista supraventricularis; posterior, right and left aortic sinus; and left ventricular outflow track (LVOFT). Photographs of the ENDO (Fig. A⇓) and EPI (Fig. D⇓) aspects of whole hearts through blocking (B–F) are compared to photomicrographs of orthogonal transverse (with respect to the annulus) plane serial sections, stained with Goldner Trichrome with Light Green, initially at intervals of .5 mm.
RESULTS: The proximal AV bundle (PAVB) is in the superomid-AVJR (Fig. B⇓, Ca, Fa). AVN and DAVB are at the base of ML on the right (Fig. B⇓, Cb, Cc), and at the base of LVOFT in the posterior-left interleaflet triangle, in thin slip of the central fibrous body, AVS-mem (Fig. E⇓, Fd, Fc) on the left. Right bundle branches at VS-mem of LVOFT. PAVB and AVN are some distance from the CSO.
CONCLUSIONS: An accurate knowledge of the topography and histology are needed to make clinical and surgical procedures safer.