The venous drainage of the human myocardium

New cardiological techniques such as coronary sinus catheterization and selective catheterization of the cardiac veins permit the opening of new experimental and clinical fields, for instance in venous angiography and the reverse nourishment of myocardium which is endangered by ischemia,and also in the electrophysiological study of the components of the conduction system. New approaches in heart surgery, such as the removal of accessory pathways of the conduction system (as in WPW syndrome), necessitate the realization of the topographical relationships of the vessels in the various sections of the coronary sulci in a different way. The objective of this work is, therefore, to present comprehensive and almost new macro- and microanatomical data about the venous drainage of the myocardium via the coronary sinus and its related and unrelated (non-coronary) cardiac veins. Examination of meticulously dissected heart specimens (of individuals who had achieved old or extreme old age at the time of their death in Germany: n=250) as well as corrosion casts of adult cardiac vessels (of individuals of all ages, n=25) formed the basis for the exact description and documentation of the occurrence, frequency, origin, and courses of both the normal and anomalously developed human coronary sinus and cardiac veins. A wide range of morphological and experimental references was consulted in order to enable thorough discussion of the anatomical findings in the light of modern cardiological diagnostics and treatment. The anatomical and clinical nomenclature is presented and there is a brief comment on modern diagnostic techniques and their applications where the cardiac veins are concerned. The two principal and one compound cardiac venous system are defined and discussed with reference to the existence of both the normal and anomalous coronary sinus and cardiac vein. 1. The greater (major) cardiac venous system (2) The smaller (minor) cardiac venous system (3)The compound cardiac venous system. The microanatomy of the various proper cardiac veins is not very well explained and illustrated in old or new literature; therefore, special attention is paid in the present study to the detailed microanatomy of the cardiac venous drainage. This includes the topograpy and structural and surface anatomy of the coronary sinus (position, length and shape, diameters, area of cross-section, circumference and volume, curvature, elevation, ostial angle, enlargement, duplication, absence), and the exact enternal and internal morphological landmarks of the coronary sinus with reference to its myocardial cover, isolated myocardial belts, and "free" myocardial cords which connect the atrial and ventricular myocardium, and the atrial ostium of the coronary sinus. It is established that the frequency, distribution pattern, courses and mode of opening of the major ventricular and atrial cardiac veins and the occurrence, morphology, and efficiency of the ostial valves of the coronary sinus and its tributaries all influence the success of any selective catheter implantation and venous reperfusion technique to a great degree. There are many peculiarities of the cardiac veins which are worthy of consideration, for instance intramyocardial and aberrant courses of the anterior interventricular vein, the oblique vein of the left atrium, the posterior interventricular vein, the small cardiac vein, the posterior vein of the left ventricle, the left and right marginal veins, and the anterior cardiac veins. Various forms and courses of the intramural venous tunnel, sinus or channel of the right atrium were found and illustrated, and discussed in terms of developmental and comparative anatomy. This review incorporates a great variety of clinically significant, new morphological findings with regard to the coronary sinus and the cardiac venous system. The many anatomical peculiarities and hindrances to the catheterization of the coronary sinus and the reperfusion of (even selected) cardiac veins are documented and evaluated; the various problems which may arise in venous reperfusion due to the presence of anatomical anomalies of the coronary sinus, cardiac veins, and ostial valves (of greater or lesser efficiency) are addressed. The presentation narrows a gap in the rather incomplete knowledge of the venous drainage of the human myocardium.