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This report describes a case of an asymptomatic 18-year-old boy with a grade 1/6 ejection systolic murmur in the aortic area referred for an echocardiographic study to rule out a congenital heart disease. The patient had situs solitus, levocardia, bicuspid aortic valve, dilation of the proximal portions of the right coronary artery, and arteriovenous coronary fistula of the anomalous coronary branch originating from the anterior descending coronary artery into the main pulmonary artery. In addition he had a unique aortic arterial meshwork constituted by arteries originating from the inferior and posterior aspect of the distal portion of the transverse aortic arch, intersegmentary arteries originating from the lateral and anterior aspect of the proximal portion of the descending aorta, and the true bronchial artery with a major arteriovenous collateral artery draining into the superior vena cava and the superior division of the left lower pulmonary vein as well as a major aortopulmonary collateral artery anastomosed with a bronchial artery and draining into the posterior aspect of the right pulmonary artery. The use of transthoracic two-dimensional color flow Doppler echocardiography, magnetic resonance angiography and multislice computed tomography to establish a detailed morphologic analysis and the presence of associated anomalies in patients with a bicuspid aortic valve are discussed.

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The purpose of this study was to describe the detailed anatomy and histology of the right atrioventricular valve apparatus in the chicken. Newborn and adult chicken hearts were studied by anatomic description, light and scanning electron microscopy, and histologic (Masson's trichrome stain) and histochemical (Sirius Red stain) techniques. Our findings indicate the presence of an incomplete fibrous annulus, a great mural leaflet, and multiple microleaflets in the right atrioventricular apparatus of the chicken heart. The great mural leaflet, essentially muscular in structure, extended from the anterior and posterior juxtaseptal commissures and was subdivided into an anterior and a posterolateral region by the attachment of the anterolateral papillary muscle. The posterolateral region presented an intermediate cleft, subdividing this region into an anterior and a posterior portion. Multiple microleaflets, which adhered to the upper right side of the ventricular septum adjacent to the right atrioventricular orifice, inserted directly into the ventricular septum via short chordae tendineae, without papillary muscles. The microleaflets were composed of smooth subendocardial connective tissue, with varying amounts of type I, II and III collagen. In addition, we observed a central fibrous body, leading to fibrous continuity between the mitral and aortic valves and the mitral and right atrioventricular valves. An atrioventricular septum was also present.(ABSTRACT TRUNCATED AT 250 WORDS)

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The processes of cellular migration, cellular differentiation and cellular multiplication are studied, since these are the basic developmental processes upon which teratogenic agents act resulting in congenital malformations. We also carefully analyze the interactions between teratogen-embryo in order to establish adequate parameters for analysis of environmental teratogens, as well as experimental teratogenesis and epidemiology. Information on the pathogenesis of congenital malformations obtained from experimental teratology in an adequate biological model, can be extrapolated to the human. The etiology of congenital malformations resulting from environmental teratogens can only be elucidated through epidemiology, since there is species specificity. Such a study must fulfill the following prerequisites: diagnosis of the congenital malformation, ruling out genetic factors in the family tree and determination of the exact time of exposure to the possible teratogen during the pregnancy.

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Fifty specimens of double outlet right ventricle were studied. The insertion of the outlet (infundibular) septum determines two types of infundibular interrelationships. In the first type, with anterior and posterior infundibulums, the outlet septum is inserted to the anterior limb of the septomarginal trabeculation; the posterior infundibulum is related with the atrioventricular orifices and the interventricular septum forms exclusively one of the walls of the posterior infundibulum. Therefore, the artery connected with the posterior infundibulum may be related with a subarterial ventricular septal defect. Of our material, 35 cases (70% of 50) had anterior and posterior infundibulums and, in 32, the aorta was connected with the posterior infundibulum (91.4% of 35). The ventricular septal defect was subaortic in 26 cases (81.2% of 32). In the second type, with side-by-side infundibulums, the outlet septum is inserted in to the ventriculo-infundibular fold in the proximity of the posterior limb of the septomarginal trabeculation. Both infundibulums are related with the atrioventricular orifices and the interventricular septum forms exclusively one of the walls of the medial infundibulum. Therefore, the artery connected with the medial infundibulum has the possibility of being related with a subarterial ventricular septal defect. Of our material, 13 cases (26% of 50) had side-by-side infundibulums. In all of these (100% of 13), the pulmonary trunk was connected with the medial infundibulum and the ventricular septal defect was subpulmonary in 12 cases (92.3% of 13). There were two cases (4% of 50) with a doubly committed ventricular septal defect. The insertion of the outlet septum permits one to determine the infundibular interrelationships, information which cannot be attained by taking into account the relationship of the great arteries with each other. Once the infundibular interrelationship is established, one must determine if the aorta is connected with the posterior or with the medial infundibulum, since, depending on the anatomical constitution of these infundibulums, there is the possibility of a ventricular septal defect being related with this artery. This information is indispensable before attempting the surgical correction of the double outlet right ventricle and it may be obtained by echocardiography or by angiocardiography.

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The origin and distribution of the coronary arteries was described in 39 autopsy specimens of truncus arteriosus (TA). The specimens were classified according to the number and the patterns of the truncal cusps. The position of the truncal cusps was defined in relation to intracardiac structures, namely, the atrioventricular orifices. Bicuspid truncal valves were observed in 8 cases (21%), tricuspid in 22 cases (56%) and quadricuspid in 9 cases (23%). All tricuspid valves had 2 anterior and 1 posterior cusp. Great variability in the origin of the coronary arteries was observed, with a tendency for the right coronary artery to arise from the anterior right quadrant and for the left coronary artery to arise from the anterior and left quadrant. Such a tendency was observed in 50% of the bicuspid, in 59% of the tricuspid and in 66% of the quadricuspid valves. The anatomic right ventricle was always observed to be vascularized by a right coronary artery, and the anatomic left ventricle by a left coronary artery, even in cases in which there was a single coronary trunk. The anterior surface of the right ventricle was crossed by a right coronary artery in 5 cases. A single coronary artery was observed in 7 cases (18%). Embryologic considerations are offered, especially regarding the relation between the observed variability in coronary artery patterns in TA and the absence of the truncal septation.

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The atrioventricular septum is defined and its anatomical features are described. This consists of two regions, a muscular and a membranous region. Isolated atrioventricular types of defect are described. The normal and the pathological embryogenesis of the atrioventricular septum are discussed. A definition of the interventricular septum is given and its anatomical features are described. This septum is divided into two regions, a membranous and muscular region. The muscular region is divided into three regions: inflow region or inlet, trabeculated region and outflow region or outlet. Interventricular defects are classified according to the septal regions in which they are located. The anatomical features which characterize each type of interventricular septal defect are established. A brief comment on the normal and pathological morphogenesis of the interventricular septum is made.

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The contribution of the inferior endocardial cushion of the atrioventricular canal to cardiac septation and to the development of the atrioventricular valves was studied in the chick embryo by in vivo labelling techniques. The study was performed in White Leghorn chick embryos in which the dorsal cushion was labelled at stage 20-21 (Hamburger and Hamilton, 1951), when the endocardial cushions were not yet fused. The embryos were sacrificed at stage 35 (mature heart). These experiments allow us to conclude that the inferior atrioventricular cushion gives origin to: a) that part of the cardiac septum between the septal insertion of the antero-septal leaflet of the mitral valve and the fibrous ridge which is the equivalent to the human septal leaflet of the tricuspid valve (atrioventricular septum); b) the region of the interatrial and the interventricular septa adjacent to the atrioventricular septum; c) the portion of the antero-septal leaflet of the mitral valve which inserts into the septum; d) the fibrous ridge corresponding to the septal leaflet of the tricuspid valve. Microdissection shows that, when they appear at stage 18, the superior and inferior endocardial cushions of the atrioventricular canal are in continuity, without boundaries, with both the interatrial and interventricular septa. Therefore, each atrioventricular orifice opens into its corresponding ventricle, there being no stage in the development of the chick embryo heart in which the atrioventricular orifices are connected to the left ventricle at the same time. The development of the atrioventricular canal is similar in the chick and human.

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Clinical findings are reported in 5 cases of anomalous left coronary artery originating from pulmonary trunk, with reference of ventricular function evaluated through echocardiographic and angio-haemodynamic methods. All patients were catheterized between 7 and 8 months of age. Left atrial and ventricular dilatation, diminished shortening of minor diameter and free wall thickness and septum normal values were obtained by echocardiography. Quantitative angiography of left ventricle demonstrated an elevation of end-diastolic volumes (mean values: 270% of predicted normal). The ejection phase indexes are diminished. The left ventricular mass/end-diastolic volume ratio was low in all cases. Myocardial imaging with thallium-201 demonstrated perfusion defect in lateral area of left ventricle in one patient. The electrocardiographic signs of myocardial necrosis support the diagnosis, and the echocardiographic and isotopic studies may contribute to it. The angio-haemodynamic method corroborate the diagnosis, and the myocardial pump function evaluation may help to decide the most appropriate treatment for this anomaly.

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