Coronary Arteries: Normal Anatomy With Historical Notes and Embryology of Main Stems.

Anatomy of subepicardial coronary arteries became a topic of investigation at autopsy in Florence (Italy) by Banchi in the early twentieth century, with the discovery of dominant and balanced patterns. Thereafter, in the 60's of the same century Baroldi in Milan did post-mortem injection with spectacular three-dimensional casts. Later Sones at the Cleveland Clinic introduced selective coronary arteriography for in vivo visualization of coronary arteries. In the present chapter we show these patterns, as well as normal variants of origin and course with questionable risk of ischemia, like myocardial bridge as well as origin of the left circumflex coronary artery from the right sinus with retroaortic course. As far as embryology, the coronary arteries and veins are epicardial in origin and finally connect the former with the aorta, and the latter with the sinus venosus. At the time of spongy myocardium, intramural blood supply derives directly by the ventricular cavities, whereas later, at the time of myocardial compaction, vascularization originates from the subepicardial network. The connection of the subepicardial plexus with the aorta occurs with prongs of the peritruncal ring, which penetrate the facing aortic sinuses. Septation of truncus arteriosus is not responsible for the final position of the coronary orifices. Infact in transposition of the great arteries coronary ostia are regularly located within facing sinuses of the anterior aorta.

Sudden Death and Coronary Artery Anomalies.

Congenital coronary artery anomalies (CAA) include a wide spectrum of malformations present at birth with various clinical manifestations and degrees of severity. Patients may be asymptomatic, and CAA may be an incidental finding during cardiac imaging or at autopsy. However, in other cases, ischemia-related signs and symptoms, leading to an increased risk of sudden cardiac death (SCD), often as first presentation may occur. In this chapter, we discuss the normal anatomy of the coronary arteries (CA) and the pathology of CAA at risk of SCD, including our experience with victims of SCD among the young population (age <40 years) and among athletes.

Isomerism of the atrial appendages: morphology and terminology.

BACKGROUND: Our aim is to identify the pathognomonic anatomical markers and the best terminology to describe the cardiac malformations associated with absent or multiple spleens, which are known as asplenia or polysplenia syndromes or isomerism. MATERIALS AND METHODS: We have reviewed 65 hearts with isomerism of atrial appendages of the Anatomical Collections of Congenital Heart Disease, Institute of Pathological Anatomy of the University of Padua consisting of 1800 specimens. All the hearts were classified according to sequential segmental classification. RESULTS: The incidence of isomerism was 3.6%. Of the total, 45 hearts with isomerism of right atrial appendages showed bilateral trilobed lungs, short bronchi, and absent spleen. The atrioventricular junction was univentricular in 49% of cases with a common atrioventricular valve in 91%. Pulmonary atresia and double outlet right ventricle were present in 40% and 47% of cases, respectively. Total anomalous pulmonary venous drainage and absent coronary sinus were always present. In 20 hearts with isomerism of left atrial appendages, bilateral bilobed lungs with long bilateral bronchi and multiple spleens were always found. The biventricular atrioventricular connection was present in 65% with a common valve in 30% of the hearts. The ventriculoarterial connection was concordant in 45% of cases, and aortic atresia and pulmonary atresia were both noted in 15% of each. An anomalous symmetric pulmonary venous drainage was observed in 65% of the hearts and interruption of inferior vena cava was found in 75% of cases. CONCLUSIONS: We believe that the appropriate terminology is based on the symmetrical morphology of the atrial appendages. The absence of the coronary sinus and the total anomalous pulmonary venous drainage are the markers of isomerism of the right atrial appendages. Symmetric pulmonary venous drainage and interruption of inferior vena cava are the markers of isomerism of left atrial appendages. In recent years, thanks to the improvement of clinical diagnosis and of surgical techniques these patients have the possibility to survive to adult age.

Complete Transposition of Great Arteries With Dominant Left Ventricle: Long-Term Survival in Natural History.

We report the case of an adult patient, affected by complete transposition of great arteries with ventricular septal defect, who survived until 68 years of age without surgery, thanks to the presence of a common atrium and pulmonary stenosis. (Level of Difficulty: Advanced.).

The concept of double inlet-double outlet right ventricle: a distinct congenital heart disease.

The aim of this study was to estimate the incidence and to analyze the anatomy of double inlet-double outlet right ventricle complex and its associated cardiac anomalies in our autopsy series. Among the 1640 hearts with congenital heart disease of our Anatomical Collection, we reviewed the specimens with double inlet-double outlet right ventricle, according to the sequential-segmental analysis, identifying associated cardiac anomalies and examining lung histology to assess the presence of pulmonary vascular disease. We identified 14 hearts with double inlet-double outlet right ventricle (0.85%). Right atrial isomerism was observed in 10 hearts, situs solitus in 3 and left atrial isomerism in one. Regarding the mode of atrioventricular connection, all hearts but one had a common atrioventricular valve. Systemic or pulmonary venous abnormalities were noted in all patients with atrial isomerism. In nine patients a valvular or subvalvular pulmonary stenosis was present. Among the functionally "univentricular hearts", double inlet- double outlet right ventricle represents a peculiar entity, mostly in association with right atrial isomerism. Multiple cardiac anomalies are associated and may complicate surgical repair.

The Spectrum of Congenital Heart Disease with Transposition of the Great Arteries from the Cardiac Registry of the University of Padua.

Transposition of the great arteries (TGA) is a cardiac condition in which the arterial trunks arise from the inappropriate ventricle: the aorta from the right ventricle and the pulmonary trunk from the left ventricle [discordant ventriculo-arterial (VA) connection]. In complete TGA, the discordant VA connection is associated with situs solitus or inversus and concordant atrioventricular (AV) connection. The hemodynamic consequence of these combined connections is that systemic and pulmonary circulations function in "parallel" rather than in "series". The presence of situs solitus or inversus associated with both AV and VA discordant connections characterizes a different anatomical complex known as "corrected TGA." In these hearts, the double discordance at AV and VA levels permits a normal sequence of the blood flow from the right atrium to the pulmonary artery and from the left atrium to the aorta. The systemic and pulmonary circulation in these hearts functions regularly in series, and the blood sequence is "physiologically corrected." Thus, the term transposition, either complete or corrected, identifies two precise, different anatomical complexes, both characterized by VA discordance. However, among congenital heart disease (CHD), there are other anatomical complexes with discordant VA connection in the setting of isomeric atrial situs (right or left) or of univentricular AV connections (double inlet or absent connections). In these latter conditions, the term "transposition" is still necessary to stress that the great arteries are "transposed" in relation to the ventricular septum (aorta from the right ventricle and pulmonary trunk from the left ventricle) but certainly does not figure out the anatomical complexes named complete or corrected transposition. We reviewed the hearts with discordant VA connection of our Anatomical Collection, consisting of 1,640 specimens with CHD, with the aim to discuss the anatomy and the frequency of the anatomical variants of TGA and to clarify terminology and classification. The knowledge of the precise anatomy of these malformation are really important for clinical diagnosis and surgical planning.

Preserving the pulmonary valve during early repair of tetralogy of Fallot: Anatomic substrates and surgical strategies.

OBJECTIVE: To describe the anatomy of the PV in tetralogy of Fallot (TOF) and to define the influence of PV anatomy on the development of surgical techniques for PV preservation during early repair. METHODS: The PV was evaluated in 79 anatomic specimens of patients with TOF who had not undergone surgery for repair, and in 82 patients who underwent early TOF repair at our institution. New surgical techniques for PV preservation during early repair are described. RESULTS: The PV in TOF was predominantly bicuspid (n = 118 of 160; 73.7%), less frequently tricuspid (n = 28 of 160; 17.5%), and seldom unicuspid (n = 14 of 160; 8.8%). In 82 cases (51.3%), the PV cusps were normal; in 78 cases (48.7%), they were thickened and dysplastic. Preservation of the PV was possible in 46 of 82 (56%) consecutive patients during TOF repair in our more recent experience, either using balloon dilation alone (18 of 46; 39%) or in association with other PV plasty procedures (28 of 46; 61%). Most bicuspid and tricuspid valves were salvageable, but unicuspid valves were not suitable. After a median follow-up time of 2.8 years (range, 0.5-6.8 years), the degree of PV regurgitation continued to be zero or mild in 40 patients (86%), and moderate in 6 (14%). CONCLUSIONS: The majority of patients with TOF (>90%) have a bicuspid or tricuspid PV, which is the most favorable surgical anatomy for preserving the PV, independent of the degree of leaflet dysplasia. The recent introduction of more-complex PV plasty techniques, such as delamination plasty, allowed us to further extend the applicability of PV-preservation techniques.

The new concept of univentricular heart.

The concept of univentricular heart moved from hearts with only one ventricle connected with atria [double inlet ventricle or absent atrioventricular (AV) connection] to hearts not amenable to biventricular repair, namely hearts with two ventricles unable to sustain separately pulmonary and systemic circulations in sequence. In the latter definition, even hearts with one hypoplastic ventricle are considered "functional" univentricular hearts. They include pulmonary/aortic atresia or severe stenosis with hypoplastic ventricle, and rare conditions like huge intramural cardiac tumors and Ebstein anomaly with extreme atrialization of right ventricular cavity. In this setting, the surgical repair is univentricular with "Fontan" operation, bypassing the ventricular mass. In other words, functionally univentricular heart is a condition in which, after surgery, only one ventricle sustain systemic circulation. Univentricular hearts (double inlet or absent AV connection) almost invariably show two ventricular chambers, one main and one accessory, which lacks an inlet portion. The latter is located posteriorly when morphologically left and anteriorly when morphologically right. As far as double inlet left ventricle, this is usually associated with discordant ventriculo-arterial (VA) connection (transposition of the great arteries) and all the blood flow to the aorta, which takes origin from the hypoplastic anterior right ventricle, is ventricular septal defect (bulbo-ventricular foramen) dependent. If restrictive, an aortic arch obstruction may be present. Double inlet left ventricle may be rarely associated with VA concordance (Holmes heart). As far as double inlet right ventricle with posterior hypoplastic left ventricular cavity, ventriculo-arterial connection is usually of double outlet type; thus the term double inlet-outlet right ventricle may be coined. Absent right or left AV connection may develop in the setting of both d- or l-loop, whatever the situs. In this condition, the contra-lateral patent AV valve may be either mitral or tricuspid in terms of morphology and the underlying ventricle (main chamber) either morphologically left or right. Establishing the loop, whatever right or left (also called right or left ventricular topology), is a fundamental step in the segmental-sequential analysis of congenital heart disease.

Situs inversus with dextrocardia in a mummy case.

A mummy of a young woman, who died due to tuberculous peritonitis and salpingitis, is conserved in the Pathological Anatomy Museum of the University of Padua. It was found at autopsy to have situs inversus of viscera with dextrocardia, apparently in the absence of other congenital defects. A 64-section scanner computed tomography (CT) on the specimen was carried out to investigate the internal condition of organs. The CT revealed the presence in the heart of a muscular ventricular septal defect and of calcific deposits on visceral pericardium and aortic wall, in keeping with sequelae of previous tuberculous pericarditis.

Juxtaposition of the atrial appendages.

Juxtaposition of the atrial appendages is a rare congenital cardiac malformation, with the appendages both located on the left or right side of the great arteries. It is usually associated with cyanotic congenital heart disease. The aim of this report is to illustrate the anatomical features of normal and juxtaposed atrial appendages, with a review of the associated anomalies. In the Anatomical Collection of Congenital Heart Disease of the University of Padua, consisting in 1,526 specimens, we found 17 (1.1%) cases of atrial appendages juxtaposition with left juxtaposition in 15 (88%) and right juxtaposition in 2 (12%). Complete form was present in 11 cases and partial form in 6. In left juxtaposition, the situs was solitus in all, and the most frequent anomalies were complete transposition of great arteries in 9 (60%) and tricuspid atresia in 5 (33%); anomalies of position of the heart in the thorax (dextro-mesocardia) were present in 46% of cases, hypoplastic right ventricle in 73%, abnormal relation of the great arteries and subaortic or bilateral infundibulum in all. In right atrial juxtaposition, the atrial situs was solitus with mitral and pulmonary atresia in one case and left isomerism with aortic atresia and double-inlet right ventricle in the other. In describing this malformation, we propose to maintain the use of a positional definition using the terms right and left juxtaposition to describe the presence of both the appendages on the right or on the left side of the great arteries, respectively. The use of a morphological definition should be added in cases of situs inversus or isomerism, with description of the morphology of the appendage located in the wrong position.

Bone-marrow-derived CXCR4-positive tissue-committed stem cell recruitment in human right ventricular remodeling.

The epicardium contributes to cardiac formation, particularly during embryogenesis. It remains to be seen if it is also involved in postnatal myocardial homeostasis. This study evaluates the topographic distribution of stem cells (c-Kit) and extracardiac progenitor cells (CXCR4+) and their contribution to ventricular remodeling in a model of pressure volume overload leading to right ventricle hypertrophy. Eleven specimens with hypoplastic left heart syndrome were evaluated and compared with 6 normal hearts from subjects matched for age and weight. All underwent Norwood procedure with the right ventricle becoming a systemic one, with pressure and volume overload leading to right ventricle remodeling. Transmural cardiac tissue samples from the right ventricle were analyzed by immunohistochemistry and morphometry. This is the first study to demonstrate that c-Kit-positive progenitor cells and tissue-committed stem cells (CXCR4+/CD45-) are higher in children with systemic right ventricle remodeling. We also show that the localization of cardiac progenitor and recruited CXCR4+ stem cells in the myocardium is site specific in hearts with right ventricle hypertrophy. These cells are mainly scattered in the interstitium of the epicardial layer. In contrast, myocyte proliferation is not a key process in right ventricular hypertrophy. Induced by the overexpression of SDF-1α by the myocardium, CXCR4 cell mobilization resembles SDF-1 homing factor distribution, showing transmural enhanced expression from the endocardium toward the epicardium. The study provides evidences of the site-specific epicardial localization of stem cells in a model of pressure/volume overload and suggests that the epicardium acts as a permissive niche in normal and pathologic conditions.

Anatomical and pathophysiological classification of congenital heart disease.

Congenital heart diseases (CHD) consist of defects of the cardiac architecture which interfere with the venous drainage, septation of the cardiac segments and their sequences and regular function of the valve apparatuses. In the normal heart the segments are disposed in such a way to allow deoxygenated venous blood to go to the lungs through the pulmonary artery and the oxygenated venous blood to go to the systemic organs through the aorta without mixing. Small and great circulations are in sequence, with no communication to each other. Establishing the sequence of cardiac segments is the prerequisite for planning a surgical repair. We propose a pathyphysiological classification of CHD based upon the clinical consequence of structural defects on the physiology of blood circulation. We divided cardiac anomalies in: (1) CHD with increased pulmonary blood flow (septal defects without pulmonary obstruction and with left-to-right shunt); (2) CHD with decreased pulmonary flow (septal defects with pulmonary obstruction and with right-to-left shunt); (3) CHD with obstruction to blood progression and no septal defects (no shunt); (4) CHD so severe as to be incompatible with postnatal blood circulation; and (5) CHD silent until adult age.

Intracardiac echocardiography: gross anatomy and magnetic resonance correlations and validations.

PURPOSE: The feasibility and safety of intracardiac echocardiography (ICE) in humans, using low frequency transducers, and its excellent tissue contrast capabilities that enhances the differentiation of intracardiac structures have been previously demonstrated. However, correlations among ICE imaging and anatomic sections or magnetic resonance (MR) scan planes have never been described before. This study was designed to correlate a simplified ICE approach with the anatomy of the right atrium and great vessels obtained by serial post-mortem sections and cardiac MR images. METHODS: A stepwise approach to ICE, which is based on our experience on over 300 consecutive patients with interatrial communications, has been correlated with anatomic sections from pressure-perfused-fixed hearts and spin echo cardiac MR imaging. A 9F-9 MHz mechanical device was used to record four transverse and one longitudinal sections for an extensive evaluation of the intracardiac architecture. RESULTS: ICE transverse and longitudinal views allowed the detection of all the required information. Moreover, the anatomic sections and cardiac MR scan planes allowed validation of all the structures imaged by ICE. The potential clinical applications of the ICE technique are further discussed. CONCLUSION: This paper demonstrates the basic accuracy of this new imaging modality. Therefore, mechanical ICE might be considered an active investment in cardiac catheterization laboratories, specifically in the percutaneous interventional procedure setting, discovering a new route (let's see and treat) to sophisticated interventions. In this respect, there can be little doubt that the knowledge of cross-sectional mechanical ICE imaging provides the basis for understanding the heart anatomy.

Fatal outcome in Eisenmenger syndrome.

AIM: To assess correlations between fatal outcome and histologic findings of pulmonary vascular disease in different situations of Eisenmenger syndrome, either during the natural course or early-late after surgery. MATERIAL AND METHODS: The clinical follow-up and fatal outcome of 20 patients affected by Eisenmenger syndrome were investigated. In addition to the pathologic report and gross reexamination of the heart, the lung tissue was studied by histology. Patients were divided into three groups: 6 non-operated patients who died during the natural course (Group 1), 11 patients who underwent correction of the congenital defect and died in the perioperative period (Group 2), and 3 patients who died late after surgery (Group 3). RESULTS: In Group 1, five patients (83%) died of cardiac arrest a few days after the onset of hypoxic attacks; in four patients histology showed Grade IV pulmonary vascular disease with diffuse fibrinoid necrosis in the distal pulmonary arterial vasculature. In Group 2, nine patients (82%) died on the first or second postoperative day after a refractory pulmonary hypertensive crisis, with histologic evidence in three patients of fibrinoid necrosis of the distal pulmonary small arteries and arterioles. In Group 3, two patients (67%) died suddenly, 6 and 18 years after cardiac surgery, following onset of dyspnea and cardiogenic shock; autopsy showed aneurysmal dilatation of the pulmonary artery with massive thrombosis in the setting of Grades III-IV pulmonary vascular disease without fibrinoid necrosis. CONCLUSION: Fatal outcome in Eisenmenger syndrome, either in the natural course or after refractory hypertensive attacks post surgery, is frequently associated with fibrinoid necrosis of the small pulmonary arteries and arterioles.

Fatal aortoesophageal fistula in two cases of tight vascular ring.

Vascular rings are rare vascular congenital anomalies causing oesophageal and tracheal compression. An aortoesophageal fistula is a devastating, in part iatrogenic, complication of vascular rings. It is seen with increasing frequency, and can be misleading, since differential diagnosis with other causes of haematemesis and melaena is often difficult, especially in infants. We report two infants with aortoesophageal fistulas secondary to double aortic arches forming a vascular ring. In both, the diagnosis was missed, and massive haemorrhage led to death. In both cases, the fissuration on the oesophageal and aortic sides of the fistula had sharp edges, highly suggestive of an iatrogenic laceration caused by manipulation of nasogastric tubes. The key for the diagnosis of vascular rings is, therefore, clinical suspicion and awareness of this condition. Prompt identification in infants with stridor, wheezing, or respiratory distress can prevent prolonged intubation, thus avoiding the formation of an aortoesophageal fistula and hopefully preventing a fatal outcome.