The atrioventricular conduction system of the beef heart

Abstract

This report is concerned with the macroscopic distribution of the conduction system in the ventricles of the beef heart as revealed by multiple injections and subsequent dissection of more than fifty specimens.Hearts were obtained directly from the slaughterhouse and the residual blood was immediately washed out by passing a stream of tap-water into the coronary arteries. The specimens were then placed in an ice-box for forty-eight hours to permit rigor mortis to pass off, this preliminary step being of considerable value in facilitating the spread of the injection material.The following procedure was adopted for exposure of the inner ventricular surfaces with minimal injury to the conduction system. To open the left ventricle, first slit the wall of the left auricle posteriorly as far as the auriculoventricular groove, and then cut through the ventricular wall from base to apex in a plane midway between the two papillary muscles.As there are no obvious external landmarks, it is well to pass a finger into the ventricular cavity between the two papillae and use it as a guide. Slit the aorta so as to pass between the posterior and left cusps1 of the semilunar valve, and continue the cut through the wall of the left auricle and anterior cusp of the mitral valve. Finally, transect all chordae tendineae. To open the right ventricle, first slit The B.K.A. has been followed in the nonienclature of the valve cusps.

Regional Distribution of Glycogen and Phosphorylase in the Ventricles of the Heart

“…Our studies have shown high concentrations of glycogen throughout the right bundle branch and higher amounts in the subendocardial layers compared to subepicardial layers of the ventricles. These results, coupled with the anatomical findings of Cardwell and Abramson, 7 suggest that the concentration gradients which we observed are probably related to the distribution of the conduction system, since the number of Purkinje fibers decrease from endocardium to epicardium. This is also indicated by the lower values for glycogen concentration observed in the base of the heart compared to the apex.…”

Anatomy and histology of the specialized tissues of the heart of the domestic cat (<i>Felis catus</i>)

“…with the tips of their ventricles cut off, for spontaneous removal of the blood. The hearts were fixed in 10% neutral formalin and then kept in the refrigerator for 48 h. The interior of the heart was exposed with minimum injury to the conducting system by following the procedure described by Cardwell and Abramson [1931] and the gross anatomy of the conducting system was studied. For microscopic examination of the sinuatrial node, atrioventricular node and the atrioventricular bundle.…”

Crista Supraventricularis Purkinje Network and Its Relation to Intraseptal Purkinje Network

“…Following that, they were frozen (−20°C) and thawed before use. Some hearts were opened as previously described (Cardwell and Abramson, ) and others opened with a cut along the septal margin from the right atrium to the pulmonary valve (Fig. A).…”

“…In particular, he described the presence of Purkinje cardiomyocytes on deep muscular layers of the septum but he doubted the existence of connections between the right and left Purkinje system terminal ramifications (Tawara ). Using the India ink injection combined with micro dissection, some authors found that the ink injected in one side of the septum could be detected filling parts of the superficial network of the other side in calf hearts (Cardwell and Abramson ). Our previous data (De Almeida et al ) confirmed the occurrence of intraseptal Purkinje cardiomyocytes using India ink and computer tomography but we were unable to determine an unquestionable demonstration of a septal network communicating both right and left Purkinje networks.…”