The arterial blood supply of the conducting system in normal human hearts

The distributing artery of the conducting system of the heart is occasionally injured in cardiac surgery. The aim of this study was to define the anatomic characteristics of the principal arterial source of the sinu-atrial node and atrioventricular node. Furthermore, the morphology of the tendon of Todaro was clarified. Thirty hearts were studied by gross anatomic methods, and the exact area of the conducting system was supported by histologic observations of four hearts. The sinu-atrial node was supplied by the right coronary artery more frequently (73% of cases) than by the left (3%), and in 23% of cases this node was supplied by both coronary arteries. The atrioventricular node was supplied by the right coronary artery (80% of cases) more than by the left (10%), and in 10% of the cases this node was supplied by both coronary arteries. The atrioventricular bundle branch arose from the right coronary artery in 10% of cases, the left coronary artery in 73%, and both coronary arteries in 17%. Most of the blood to the right bundle (the moderator band) was supplied by the interventricular septal branches of the anterior interventricular branch from the left coronary artery. Finally, all the arteries of the right bundle and left bundle were defined to be derived from left coronary arteries.     

Comparative morphology of the trabecula septomarginalis in terrestrial mammals]

The authors studied macroscopic morphology and histologic structure of the moderator band - trabecula septomarginalis - in 100 earthly mammals. A real trabecula septomarginalis was never found in carnivora (dog and fox) because the "anterior" papillary muscle of the right ventricle is located on the lower part of the septum ventriculorum or at times bridge-shaped above the anteiror interventricular groove and attached on both septum and anterior wall of the right ventricle. On the opposite, in ungulates, a well-known band runs across the right ventricular chamber from the septum close to the musculus papillaris coni arteriosi up to the anterior wall close to the anterior papillary muscle. In fact the attachments lie more or less approximate to the pillars; in suidae, the trabecula usually ends on a vertical trabecula carnea just under Luschka's muscle. Three types of trabecula septomarginalis were encountered as previously described by Bortolami in ox: - Mostly (66%), the trabecula septomarginalis is a short and thick fleshy column. The ratio Length mm Thickness mm amounts to about 4 to 7 and can be regarded as reasonably constant within each variety. Moreover the quotients Length mm Height of septum MM. and Thickness of the trabecula mm Highest thickness of the anterior wall mm (measured just beneath the tricuspid attachment) keep constant in each group; thus it may be concluded that size and shape of the trabecula depend on the volume of the heart and the age of the animal. - Rarely, the trabecula looks like a tendinous cord. Such a fibrous string is nearly constant in suidae, especially in wild boar, but seldom in bovidae and cervidae. In all cases, the trabecula septomarginalis supports the right branch of the atrioventricular bundle and a thin artery which originates from the left coronary artery and branches into the right coronary vessels within the anterior papillary muscle. Some venous capillaries were also observed but only in the muscular trabeculae; they are not constant and mouth into the right ventricular chamber or run towards the septal veins around the atrioventricular node. Therefore whatever is the size, the trabecula septomarginalis must be regarded as the shortest pathway from the septum to the anteiror wall of the right ventricle and is a mere band bearing the "right nodal pedicle".     

Anatomy and vasculature of a minke whale heart

The heart from a 4-m-long minke whale (Balaenoptera acutorostrata) was studied to determine the details of its anatomy and to consider cardiac adaptations to diving. The volume fraction (Vvc) of capillaries in the wall of the left ventricle was determined at different levels from base to apex and at different depths from epi- to endocardium using a light microscopic stereologic technique. Typical of cetaceans, this minke whale heart was distinctly flattened dorsoventrally. A moderator band, characteristic of ungulate hearts, spanned the right ventricle. The right and left atrioventricular valves were tricuspid and bicuspid, respectively. The right coronary artery supplied the dorsal and right lateral myocardium. The left coronary artery supplied the ventral and left lateral myocardium. An anastomosis between the dorsal and ventral interventricular arteries occurred in the dorsal interventricular groove. Stereologically, a decreasing transmural gradient in Vvc was identified between the epicardium and the subepicardium at 15 cm from the apex. Our results, however, did not reveal any significant deviations in the pattern of capillary distribution in the wall of the left ventricle between this baleen whale and terrestrial mammals. Measurements of the heart, great vessels, coronary vasculature, and ventricular walls are also given, and they suggest a physiologic and adaptive right ventricular hypertrophy. Based on these and other observations, we propose that the relatively great thickness of the right ventricle and the distinctive shape of the cetacean heart are adaptations to the hemodynamic changes and collapse of the thorax associated with apneic diving.     

The coronary vessels in the heart of a marsupial,Trichosurus vulpecula

The coronary arteries and veins are described in the phalanger (Trichosurus vulpecula), an Australian marsupial, after study of 16 hearts. Several hearts were prepared by injection of the vessels with either latex or vinyl plastic. The distributing branches of both coronary arteries are within the myocardium and are not visible on the surface of the heart. The right coronary artery arises in typical fashion and supplies the non-septal wall of the right ventricle almost entirely, the dorsal half of the interventricular septum, the dorsal part of the non-septal wall of the left ventricle and part of the right artium and its ventral auricle. The left coronary artery also arises typically and supplies the greater part of the non-septal wall of the left ventricle, the ventral part of the interventricular septum, part of the infundibulum, the left atrium and part of the right atrium. At its origin it is larger than the right coronary artery. The ventral and dorsal septal arteries have an unusual course lying in the subendocardial tissue of the right ventricle. It is believed that arteries in this position have not been described previously. The great cardiac vein opens directly into the right atrium. A typical coronary sinus is present but formed only from veins draining the dorsal aspect of the heart. It is concluded that the coronary circulation in T. vulpecula closely resembles that of the avian heart and is unlike both the monotreme and placental mammalian patterns.     

Anatomical study of a left single coronary artery with special reference to the various distribution patterns of bilateral coronary arteries

A left single coronary artery of heart was observed during anatomy practice at Kumamoto University School of Medicine in a 73-year-old female cadaver who died from a thalamic hemorrhage. The left single coronary artery, having a single orifice in the left aortic sinus, bifurcated into the anterior interventricular (IVa) and circumflex (CIR) arteries. No orifice of the right coronary artery was found on the aortic wall. Giving off a branch which traversed the upper part of the infundibulum to supply the anterior upper region of the right ventricle, the IVa descended in the anterior interventricular sulcus to supply the apex of the heart. The CIR curved leftwards in the atrioventricular sulcus to reach the posterior surface, after which it continued to emerge again into the anterior surface. The atrial arteries showed no anomalous distribution pattern and histological observation revealed no pathological abnormality other than a slightly thickened tunica intima. Furthermore, we observed the distribution patterns of bilateral coronary arteries in 377 hearts dissected during anatomical practice over 13 years at Kanazawa University (1980–1986) and Kumamoto University (1993–1998). Although the reason why only the right coronary artery was absent is left unexplained, it was concluded that the left single coronary artery in this study, having the developed left conal and circumflex branches, was an extreme case of the left dominant series of coronary arteries. The formation of single coronary arteries can be explained embryologically by the change of flow in the capillary plexus established on the ventricle wall.     

Gross heart anatomy of <Emphasis Type="Italic">Arctocephalus australis</Emphasis> (Zimmerman, 1783)

Little research has been carried out on the gross visceral anatomy of the Otariidae, and the anatomical information for the southern fur seals, Arctocephalus spp., is scant. The aim of the present study was to describe the external and internal conformation, and the sanguineous irrigation of the heart of Arctocephalus australis. Twelve hearts of Arctocephalus australis were studied by simple dissection. In the right ventricle the trabeculae carneae were well developed and there were three or more papillary muscles. In the left ventricle there were two papillary muscles, subatrialis and subauricularis, attached to the parietal wall. There was also a great development of trabeculae carneae which occupied almost all of the ventricle, from the left atrioventricular valve up to the proximities of the expulsion route. A large quantity of muscular strands were found extending themselves between the trabeculae carneae, becoming more dense and forming a network when near the apex. The distribution of the branches of the coronary arteries was highly variable and no heart was similar to another one in this sense. In the majority of the hearts the subsinosal interventricular branch proceeded from the right coronary artery. It is concluded that there were many differences between the heart of the Arctocephalus australis and the heart of the domestic dog, contrary to what has been suggested for other genera of Otariidae.     

The distribution of ischaemia in perfused Wistar rat hearts following coronary artery occlusion.

Ischaemia induced in Wistar rat hearts by ligation of the main coronary arteries, was studied by NADH-fluorescence photography. The coronary anatomy was examined by barium angiography and intravascular resin infusion and it was confirmed that the main arteries were the left and right coronaries and the septal artery. The septal artery branched from the right coronary orifice in 90% of hearts examined. The long-axial cross-sectional view of the heart showed the ischaemic area to be limited to the left ventricular free wall following ligation of the left coronary, to the right ventricular free wall following ligation of the right coronary artery and to the ventricular septum after ligation of the septal artery. When the left coronary artery was ligated at its origin, the ratio of ischaemic area to cross-sectional area increased from the base to the apex of the heart. The borders of the epicardial ischaemic area induced by left and right coronary ligation made contact without any overlapping or broad separation. This indicates that the area perfused by the left and right coronary arteries was contiguous but physically separated.     

Functional dominance of the right coronary artery: Incidence in the human heart

After injection of radiopaque medium, 200 human hearts were studied by direct observation and x-ray analysis. The right coronary artery (RC) was dominant in 178 of these hearts as characterized by giving off the typical posterior interventricular artery (PIV), the posterior descending artery. Within this group, 19 specimens had right coronary arteries that gave off both a large posterior interventricular artery (LPIV) and a branch that continued beyond the crux termed a large extension of the right coronary (LERC). The subgroup of hearts supplied thusly was termed real right dominant (RRD). The RC in these hearts supplied the right ventricle and almost half of the left ventricle. These findings explain why proximal lesions of the RC in RRD hearts can be associated with extensive posterolateral ischemia and mitral dysfunction and should be of practical importance when considering angioplasty or by-pass surgery. The diameters and lengths of the arteries of the RC in RRD hearts were measured and compared with the same parameters in typical right dominant hearts. © 1996 Wiley-Liss, Inc.     

Investigation of coronary arteries in the porcupine (Hystrix cristata) by latex injection and angiography

Coronary arteries were investigated in the porcupine by means of angiography performed on each of 5 adult porcupines (3 male, 2 female) which was followed by injection of a colored latex mixture from the aortic arch for the demonstration of these arteries. The results showed that the aorta branched out at the level of the cardiac outlet to form the left and right coronary arteries and right ramus coni arteriosi. Coronary arteries coursed and ramified in the myocardium. The left coronary artery divided to form the paraconal interventricular artery and left circumflex artery when it reached the coronary sulcus. The interventricular septum was vascularized by the septal branch of the paraconal interventricular artery and by the small septal branches. The left and right coronary arteries gave off all the branches reported in the literature for other species. When the ramus coni arteriosi originates from the right coronary artery, it is designated a third coronary artery. In conclusion, it was found that the coronary arteries of the porcupine had an "intramyocardial course" as in other rodents. The coronary supply of the heart represented a "left coronary type" which was similar to those of carnivores and ruminants. The results of this study may contribute to the data in this area of science.     

心第3冠状动脉的解剖学

目的:研究心第3冠状动脉的大体解剖学数据,为临床诊治相关疾病提供依据。方法:共收集了118个福尔马林固定的心,观测心第3冠状动脉数量、来源、分布范围、营养区域和长度及管径等解剖学数据。结果:第3冠状动脉出现率为28.8%,其中单支出现率为26.3%,双支出现率为2.5%。它通常分布于动脉圆锥、右心室前壁、室间隔及心尖中的1个或多个位置,也有些少见情况:第3冠状动脉比右冠状动脉大并结束于心尖;第3冠状动脉比右冠状动脉小且结束于心尖;心肌桥覆盖较大的第3冠状动脉。结论:心存在第3冠状动脉情况较多,它与左冠状动脉前降支吻合且分布于心尖和室间隔。因此第3冠状动脉是在疾病诊疗期间需要着重考虑的一个因素。     

An endoscopic and anatomical approach to the septal papillary muscle of the conus

Many authors have questioned the gross anatomy of the septal papillary muscle of the conus known as the papillary muscle complex (PMC) during the past century. An anatomical investigation was conducted to identify the morphology and the topography of the PMC. Our study involved 200 formalin fixed adult human hearts. The PMC was present in 82% of the hearts, while in the remaining 18% of specimens, it was replaced by tendinous chords. The PMC was connected with the septal (59.7%), anterior (20.7%), or both septal and anterior leaflets (19.5%) with single (29.8%) or multiple chordae tendinae (70.1%). The PMC was also found to be present as a single papilla (51.8%), double papilla (32.9%) or triple papilla (15.2%). In addition to the PMC, we observed accessory single septal papillary muscles 42 specimens, double septal papillary muscles 32 specimens and triple septal papillary muscles 26 specimens. In the right ventricular inflow tract, the location of the PMC was consistently found to be in a position below the junction of the anterior and septal leaflets of the tricuspid valve. In the right ventricular outflow tract, we were able to identify 73 specimens in which the PMC was located at the junction formed superiorly by the inferior border of the subpulmonary infundibulum and inferiorly by the superior-lateral border of the septal band, extending into the region of the subpulmonary infundibulum. In the remaining 27%, the PMC was located primarily at the area occupied by the superiolateral border of the septal band without extending to the subpulmonary infundibulum. The present study describes the topography of the PMC according to its surrounding anatomical structures such as the tricuspid valve, subpulmonary infundibulum and septal band of the right ventricle. This anatomical data could have important clinical significance for cardiac surgeons operating in this area.     

Anomalous first septal perforator artery: Anatomic-clinical correlates

The interventricular septum is considered the most densely vascularized portion of the heart, containing important elements of the cardiac conduction system and providing mechanical support for both right and left ventricular function. Anatomically, this structure is perfused by the relatively small caliber anterior and posterior septal perforator branches arising from two large epicardial coronary vessels, the anterior interventricular (descending) branch of the left coronary artery and the posterior interventricular (descending) branch of the right coronary artery, respectively. In cases of significant atherosclerotic disease depriving flow in the major coronary vessels and their septal branches, an anomalous septal perforator artery can take over the task of supporting the function of the interventricular septum by supplementing essential collateral flow. © 1996 Wiley-Liss, Inc.     

The anatomy of the coronary sinus and its tributaries

The coronary sinus and its tributaries were studied by anatomical dissection in 37 adult human cadaveric hearts, which had been fixed in formalin solution. An anastomosis of approximately 1.0mm in calibre was observed between the anterior and posterior interventricular veins in 19% of specimens. Myocardial bridges were detected above the anterior interventricular vein or its tributaries in 8% of specimens. The great cardiac vein formed the base of the arteriovenous trigone of Brocq and Mouchet with the bifurcating branches of the left coronary artery in 89% of specimens and formed an angle accompanying these arterial branches in 11%. In the trigone the anterior interventricular and great cardiac veins were superficial to the arteries in 73% of specimens. The left marginal vein was present in 97% of specimens, emptying into the great cardiac vein in 81% of cases and into the coronary sinus in the remaining 19%. The small cardiac vein was present in 54% of specimens. In the coronary sulcus the great cardiac vein was adjacent to the circumflex branch of the left coronary artery in 76% of specimens and to the right coronary artery in 5% in 19% there was no relationship with either artery. The coronary sinus maintained a relationship with the right coronary artery in 46% of specimens and with the left coronary artery in 32% in 22% it had no relationship with these vessels.     

Morphogenetic aspects of the septomarginal trabecula in the human heart

Introduction

The septomarginal trabecula is a constant element of the anatomy of the human heart, which connects the interventricular septum and the anterior wall of the right ventricle. Considering the diversity of opinions about the structure and numerous studies suggesting its important role in haemodynamics and conduction of electrical impulses in the heart, we decided to study this element in detail.

Material and methods

The research was conducted on 220 human hearts. Attention was mainly paid to the structure and topography of the trabecula. Its relation to the anterior papillary muscle was also a part of the study.

Results

The presence of this morphologically diverse element was confirmed in each of the studied hearts. In most cases the trabecula originated from the upper part of the interventricular septum, separating at an angle increasing proportionally to the number of branches of the crista supraventricularis as well as the number of secondary trabeculae. The criteria established for the study, which included the course of the trabecula in the lumen of the right ventricle and its relation to the anterior papillary muscle, let us distinguish 4 types of septomarginal trabecula (I, II, III, IV). The most common was type III, the undivided trabecula, tightly connecting with the anterior papillary muscle.

Conclusions

Based on the results of the following study we propose a hypothesis on the genesis of respective parts of the septomarginal trabecula and a plausible sequence of changes they undergo during human ontogenesis and phylogenesis of the primates.     

右心室壁内的动脉构筑

本文对50例成人离体心标本分别用铸型法、X线造影法和墨汁注射火棉胶切片法作右心室壁内及乳头肌的动脉构筑研究。与左心室柑同,可将右室壁内的动脉分为心外膜支、树枝状支、直支和乳头肌支四种类型。与左心室不同的是树枝状支在右室壁内匍匐斜行一段距离后再分支到右室壁的部分或全层心肌,它也分支到达肉柱。直支以斜行或直角纵主干上发出分支分布于右室壁肌肉并可达肉柱。乳头肌血管类型有钩形和叉形,但类型较左心室乳头肌少。心壁内可见少数心内膜下丛。多数乳头肌至少有二个以上的血管供应,少数小的乳头肌为单一动脉支配呈单支中央型。用图像分析仪对左、右心室壁及乳头肌的毛细血管密度和支数进行了对比。对右室壁内和乳头肌内的小血管和毛细血管形态与心肌的关系作了观察。讨论了它们形态和功能的一致性,以及对心肌梗塞的应用意义。     

Observation of root variations in human coronary arteries

In dissection courses conducted from 1999 through to 2003, five specimens were found to have coronary arteries with variant roots and branches, as follows: in specimens 1-4, roots of the right coronary artery (RCA) and right conus branch arose independently from the right aortic sinus (RAS); in specimen 5, the RCA and left coronary artery (LCA) originated from the RAS. The LCA pierced the upper part of the muscular interventricular septum and appeared on the surface, then dividing into the anterior interventricular and the circumflex branches. In the present study, we considered that the right conus arteries in specimens 1-4 were the remnant blood capillaries around the aorta towards the RAS in the embryonic stage. In specimen 5, the vessel near the left aortic sinus was poorly developed as a small thin artery. Instead, the LCA was developed from the anterior and posterior interventricular septal branches.     

Perfusion of myocardial segments of the right ventricle: role of the left coronary artery in infarction of the right ventricle

In a series of 88 human hearts, from individuals aged between 24 h and 94 yr (x= 61.09 +/- 21.96), the coronary arterial distribution of the right ventricle was studied using a modified Selvester's system of segmentation. Postmortem angiographies and microdissection techniques were used. The analysis of the six segments of the right ventricle shows that the three anterior segments, basal, mesial, and--less frequently--apical, present a type of irrigation that is practically constant and is dual. The postero-basal and postero-mesial segments are irrigated almost exclusively by the right coronary artery. In the remaining segments the vascularization was of mixed type, although a considerable degree of exclusive arterial perfusion was observed in the antero-apical segment. The segmental analysis allows us to conclude that although arterial vascularization of the right ventricle depends fundamentally on the right coronary artery, the anterior interventricular artery irrigates more than 20% of the right ventricular myocardium. Results from segmental analysis are compared with data from clinical and necropsic studies. Copyright Wiley-Liss, Inc.     

Right superior septal artery with "normal" right coronary and ectopic "early" aortic origin: a contribution to the vascular supply of the interventricular septum of the human heart.

In the human heart, anterior and posterior septal branches are mainly responsible for the arterial supply of the interventricular septum. These arteries are the basis of efficient intercoronary collateralization. The right and left superior septal arteries also contribute to the nourishment of the septum and to any eventual collateralization. Because the right superior septal artery (RSSA) is small in diameter, short, and has a variable origin either at the proximal stem or in the ostial area of the right coronary artery, it is difficult or almost impossible to visualize it angiographically. During investigation of the arterial supply of the interventricular septum in 84 human heart specimens and 16 corrosion casts, we found a few peculiarities in the origin and pattern of the RSSA in four specimens. The RSSA was found in 27 cases (27%); in most it was a single vessel and arose from three different locations: (a) the proximal part of the right coronary artery (21 cases); (b) the right coronary ostial area (four cases); and (c) from the floor of the right (anterior) aortic sinus (two cases). Macroscopically, in 16 cases the RSSA had a length of less than 10 mm; in nine cases the arteries were between 11 and 17 mm long. In two cases the RSSA was of more substantial appearance and up to 36 mm in length; it nourished almost the entire upper third of the septal myocardium. In these two cases, two courses could be differentiated: an extramural course with the RSSA descending to the subvalvular fibrous tissue, and an intramural course with ramification in the myocardium of the crista supraventricularis and the superior parts of the interventricular septum. One cadaveric heart specimen and one corrosion cast showed RSSAs that originated "early" (ectopically) on the floor of the right (anterior) aortic sinus; their total lengths were 16 and 17 mm, respectively. Such ectopic ostia of RSSAs have never been described before in the anatomical literature. Given the intense clinical concern with the identification of possible bypass vessels in the myocardium, we assume that the RSSA may have a potential as a collateral route. These findings were also discussed in light of developmental and comparative anatomy.     

Intersection patterns of human coronary veins and arteries

Intersections between the coronary veins (CV) and arteries (CA) of 103 adult human hearts were mapped on the heart surface. Then the correlations of these intersection patterns to their localization were studied. Eight spots were selected where one of four major CV (anterior cardiac vein, middle cardiac vein, left posterior ventricular vein, and great cardiac vein) intersected with one of CA and their branches (right coronary artery, posterior interventricular branch, left posterior ventricular branch, circumflex branch, diagonal branch, and anterior interventricular branch). The great cardiac vein (GCV) ran beneath the anterior interventricular branch in 56 specimens out of 103, beneath the diagonal branch in 75 specimens out of 103, and beneath the circumflex branch in 36 specimens out of 103, while the other CV mostly ran over CA. The present observations suggest that the CV on the right side may be formed prior to CA, while the CV on the left side may be formed simultaneously with CA.