Venous System of the Myocardium with Special Reference to the Conduction System

Abstract

M~yrocardial veins and sinusoids of the right atrioventricular junction of the heart were studied in serial section, and their relations to the common conduction bundle and nodal tissues were anatomically demonstrated by wax model reconstructions. It is suggested these venous channels may well explain the complete, but transient, bundle block of children observed in certain toxic diseases. On the other hand, the same sinusoids functioning as capillaries may nourish the bundle tissues in older decades, thus explaining the low incidence of bundle block in cases of gradual coronary occlusion. The possible role of these vessels to the intercoronary circulation is discussed.T HE AUTHORS, long interested in the conduction system of the heart, found that few recent attempts have been made to evaluate and correlate the research findings from the several scientific fields of interest.' In the present study they have therefore attempted further to correlate certain well known clinical observations on the heart with lesser known facts to be found in the journals of anatomy, physiology, and pathology.In the recent literature Glomset, Glomset and Birge2-4 have denied the morphologic existence of a conduction system in the hearts of the ungulates. dog and man, whereas the studies of Truex and Copenhaver,5'f Nonidez,7 Walls,8' Robb, Kaylor and Turman,'0 Stotler and MIcMahon," and Baird and Robb'2 have presented convincing structural evidence that a specialized conduction system exists in the hearts of these animals.In the pursuit of these studies on the conduction tissue in young and adult animals, the present authors were impressed by the large number of irregular venous sinusoids which either accompanied or traversed the common bundle of conduction tissue. We have observed such vessels in serial sections of the hearts of five adult dogs, 10 newborn puppies, seven human fetuses (from four to eight months of gestation), and two human newborn.Special attention was directed toward these Brody and Smith211 found heart lesions of varying severity in over 90 per cent of the hearts studied after scarlet fever and related streptococcus infections. Three widespread lesions were described which were primarily associated with the endothelium of the capillaries and veins. The most common lesion Ad'as a lymphocytic and plasma cell infiltration beneath the ventricular endocardium, or about the endothelium of the coronary veins and thebesian vessels. Inasmuch as the venous channels involved are closely related to the common bundle of conduction tissue as it passes through, and courses superior to, the fibrous ring of the right atrioventricular orifice, a more detailed anatomic description of these vessels is in order.

Venous circulation of the human cardiac conduction system.

“…Here again, the venous drainage can be considered nigh on perfect. Truex and Schwartz (1951), using reconstruction studies, showed that the veins of the atrioventricular bundle formed a sinusoid system most frequently opening into the coronary sinus and into the atrium.…”

“…Truex and Schwartz (1951) also described the veins of the atrioventricular conduction system, but they regarded them as dilated sinusoids and maintained that they played an important role in facilitating the influence of toxins upon the conduction system.…”

Möglichkeiten einer direkt intramuralen Myokardperfusion

“…Inzwischen sind zahlreiche Untersuchungen zur Morphologie dieser sinusoidalen, intra muralen Endothelschläuche angestellt worden (2,10,20,21). Die Interpretation ihrer funk tionellen Bedeutung steht aus, und ihre Ein gliederung in das Gesamtnetz des Koronarkreislaufes ist noch nicht überzeugend gelun gen.…”