Características morfológicas y biométricas del músculo papilar septal en corazones de individuos chilenos / Morphological and biometric characteristics of septal papillary muscle in hearts of chilean individuals

Se realizó un estudio descriptivo de las características anatómicas y biométricas del músculo papilar septal en 30 corazones de individuos adultos chilenos, en edades comprendidas entre 18 y 84 años de edad, de ambos sexos, sin aparente patología cardíaca, pertenecientes a la Unidad de Anatomía Humana Normal del Departamento de Ciencias Básicas de la Universidad de La Frontera. Los resultados mostraron que el músculo papilar septal, se presenta en un 83,3 por ciento de los corazones del estudio. De éstos, el 44,0 por ciento presenta un solo músculo, el 28 por ciento presenta dos músculos y el 28 por ciento tres músculos papilares septales. De los músculos papilares septales encontrados, el 71,1 por ciento correspondió a la forma cono libre, el 24,4 por ciento a la forma cono pegado y el 4,5 por ciento a la forma puente. En cuanto a la longitud de forma cono pegado y cono libre, el rango que se encuentra en mayor porcentaje está entre 4,0 mm ­ 5,99 mm; con un 45,5 por ciento y 42,4 por ciento, respectivamente. Este estudio nos demuestra la importancia de incorporar al músculo papilar septal a la nomenclatura anatómica internacional.

A descriptive research study was carried out on the anatomical and biometric characteristics of the septal papillary muscle in 30 hearts of adult Chilean subjects, between 18 and 84 years of age of both sexes and without apparent cardiac pathology, from the Normal Human Anatomy Unit, Basic Sciences Department of the Universidad de La Frontera. Results show that the septal papillary muscle was present in 83.3 percent of the hearts in the study. Of these 44.0 percent show one muscle only, 28 percent show two muscles and 28 percent show three septal papillary muscles. In the septal papillary muscles found, 71.1 percent are free cone-shaped, 24.4 percent were attached cone-shaped, and 4.5 percent were bridge-shaped. Regarding the length of attached cone and free cone shaped, the highest percentage range was between 4.0 mm and 5.99 mm, with 45.5 percent and 42.4 percent respectively. The present study shows the importance of integrating the septal papillary muscle to the International Anatomical Nomenclature.

Forame oval permeável e sua relação com acidente vascular cerebral isquêmico (AVC) e enxaqueca / Permeable foramen ovale and its relation to ischemic stroke (stroke)and migraine

O forame oval permite, durante o período fetal, a passagem de sangue oxigenado oriundo da placenta para o átrio direito, possibilitando oxigenação adequada do cérebro e do coração. Após o nascimento, com o início da respiração e com a desconexão da placenta, há um aumento da pressão do lado esquerdo e uma diminuição do lado direito do coração, empurrando a lâmina do forame oval para a direita, o que ocasiona o seu fechamento funcional. Entretanto, em aproximadamente 25% da população ele pode permanecer patente. Sua relação com o acidente vascular isquêmico e com enxaqueca com aura tem sido sugerida em várias publicações. Na presença de acidente vascular isquêmico idiopático, tem sido sugerido por vários autores o fechamento percutâneo do forame oval patente (FOP), quando comprovada a existência de shunt da direita para a esquerda, espontaneamente ou com manobra de Valsalva. Contudo, hã necessidade de maior tempo de observação para avaliar a sua superioridade em relação ao tratamento clínico.

Foramen ovale allows the passage, during the fetal period, of oxygenated blood coming from the placenta to the right atrium, supplying adequate oxygenation for brain and heart. After birth, with onset of breathing and disconnection of the placenta, there are an increased pressure on the left side ofthe heart and a decreasing in its right side pushing the blade of the foramen ovale to the right, causing its functional closure. However, the patent foramen ovale (PFO) occurs in approximately 25% of the population. The relationship between cryptogenic stroke, migraine with aura and PFO has been suggestedin several publications. In the presence of cryptogenic stroke, percutaneous closure of PFO, when shown the existente of a shunt from right to left spontaneously or with the Valsalva maneuver, has been suggested by several authors. However, there is need of more observation time to assess its superiority over medica1 treatment.

Normal development of the muscular region of the interventricular septum. II. The importance of myocardial proliferation.

In a first paper, we concluded that the muscular region of the interventricular septum is developed by the trabecular branches and showed evidence that the developing interventricular septum elongates in a direction opposite to that of atria. Nevertheless, to date the literature is lacking precise information on the importance of myocardial proliferation not only in this process but also in the morphogenesis of the ventricular cavities. The aim of this study was to determine the spatial and temporal distribution of high-intensity foci of cycling myocytes in the ventricular region of the heart of chicken embryos during cardiac septation. Histological studies, detection of the proliferating cell nuclear antigen by light and confocal microscopy and flow cytometric analysis were carried out. The results corroborate that the developing interventricular septum grows in a direction opposite to that of atria. A remoulding mechanism that results in fenestrated trabecular sheets and trabecular branching is discussed. Our findings allowed us to summarize the normal morphogenesis of the muscular region of the interventricular septum in a way that is different from that suggested by other researchers.

Los segmentos cardíacos primitivos, su implicación en la cardiogénesis normal aplicada a la cardiología pediátrica / Involvement of the primitive cardiac segments in the normal cardiogenesis. Its importance in the pediatric cardiology

The ample development of diagnostic echocardiography in pediatric cardiology has demanded precise knowledge of the abnormal anatomy of hearts that present congenital cardiac diseases. As a result, the information on morphologic and molecular aspects of cardiac embryogenesis has become fundamental to understand the anomalous anatomy of the malformed hearts. Based on these facts, in this paper we reviewed normal cardiogenesis, integrating the new information obtained experimentally in the chick embryo and from classic descriptive knowledge in humans. The age at which each cardiac segment appears is specified. At the same time, the changes in shape, relationships and position of these cardiac segments are detailed. Some implications of this process in the production of congenital cardiac defects and the importance of some specific genes are also discussed. This information is useful in the diagnosis of congenital cardiac diseases, as well as in discussing their embryogenesis. It is also beneficial in studying the possible mechanisms and genes implicated in normal morphogenesis of cardiac chambers, septa and valves. All this knowledge is important to plan strategies to avoid the production of this type of congenital pathologies.

Defecto septal atrial. Estudio morfopatológico, embriológico / Atrial septal defect. A morphopathological and embryological study

To contribute to a better understanding of the morphopathology of atrial septal defects (ASD), we describe and classify topographically a series of hearts obtained from necropsies. We performed an anatomo-embryological correlation to gain insight on the pathogenesis of this type of congenital heart disease. Seventy-one hearts with ASD and twenty-three normal hearts with patent foramen ovale from the collection at the Instituto Nacional de Cardiologia lgnacio Chavez were studied morphologically; segmental sequential analysis was used. The topography of the interatrial septum was determined on the basis of the structures related to it in order to classify the ASD. The FS area was projected on the right septal surface using pins. To stablish the anatomo-embryological correlation, the ASD's anatomy was compared with the embryological processes that take place in atrial septation. The most frequent ASD was the OO type (FS) with 64.78%, followed by common atrium, true FS, FP, superior and inferior sinus venosus, types each one with 2.81% and one coronary sinus venosus type (1.40%). The FS area was projected below the superior vena cava. The morphologically and topographically knowledge of atrial septal defect is useful to interpret the imaging studies of this cardiopathy and is basic for the surgeon and the interventionist cardiologist. Abnormal apoptosis and retarded developmental growth are proposed as pathogenic mechanisms.

[Atrial septal defect. A morphopathological and embryological study]. / Defecto septal atrial. Estudio morfopatológico, embriológico.

To contribute to a better understanding of the morphopathology of atrial septal defects (ASD), we describe and classify topographically a series of hearts obtained from necropsies. We performed an anatomo-embryological correlation to gain insight on the pathogenesis of this type of congenital heart disease. Seventy-one hearts with ASD and twenty-three normal hearts with patent foramen ovale from the collection at the Instituto Nacional de Cardiologia lgnacio Chavez were studied morphologically; segmental sequential analysis was used. The topography of the interatrial septum was determined on the basis of the structures related to it in order to classify the ASD. The FS area was projected on the right septal surface using pins. To stablish the anatomo-embryological correlation, the ASD's anatomy was compared with the embryological processes that take place in atrial septation. The most frequent ASD was the OO type (FS) with 64.78%, followed by common atrium, true FS, FP, superior and inferior sinus venosus, types each one with 2.81% and one coronary sinus venosus type (1.40%). The FS area was projected below the superior vena cava. The morphologically and topographically knowledge of atrial septal defect is useful to interpret the imaging studies of this cardiopathy and is basic for the surgeon and the interventionist cardiologist. Abnormal apoptosis and retarded developmental growth are proposed as pathogenic mechanisms.

[Involvement of the primitive cardiac segments in the normal cardiogenesis. Its importance in the pediatric cardiology]. / Los segmentos cardíacos primitivos, su implicación en la cardiogénesis normal aplicada a la cardiología pediátrica.

The ample development of diagnostic echocardiography in pediatric cardiology has demanded precise knowledge of the abnormal anatomy of hearts that present congenital cardiac diseases. As a result, the information on morphologic and molecular aspects of cardiac embryogenesis has become fundamental to understand the anomalous anatomy of the malformed hearts. Based on these facts, in this paper we reviewed normal cardiogenesis, integrating the new information obtained experimentally in the chick embryo and from classic descriptive knowledge in humans. The age at which each cardiac segment appears is specified. At the same time, the changes in shape, relationships and position of these cardiac segments are detailed. Some implications of this process in the production of congenital cardiac defects and the importance of some specific genes are also discussed. This information is useful in the diagnosis of congenital cardiac diseases, as well as in discussing their embryogenesis. It is also beneficial in studying the possible mechanisms and genes implicated in normal morphogenesis of cardiac chambers, septa and valves. All this knowledge is important to plan strategies to avoid the production of this type of congenital pathologies.

Mobility of the Septum primum does not depend on the foramen ovale diameter in normal fetuses.

OBJECTIVE: To test the hypothesis that a correlation exists between the maximum foramen ovale diastolic diameter and the excursion index (EI) of the septum primum in normal fetuses. METHODS: One hundred and two normal fetuses with gestational ages ranging from 20 to 40 weeks were submitted to echocardiography. The foramen ovale diameter and the "maximal excursion" of the septum primum were measured in a 4-chamber view. The data were analyzed by Pearson's correlation coefficient. RESULTS: The mean foramen ovale (FO) diameter was 5.06 +/- 1.29 mm; the maximal excursion of the septum primum was 5.42 +/- 1.41 mm; the left atrium diameter 11.47 +/- 2.76 mm; the septum primum "excursion index" was 0.48 +/- 0.09. Mean FO/EI ratio was 11.35 +/- 3.94 mm. No FO/EI correlation (r = -0.03) existed, and a weak foramen ovale/left atrium correlation (r = 0.31) was observed, as well as a weak foramen ovale/excursion of septum primum correlation (r = 0.21). CONCLUSION: Septum primum mobility does not depend on the foramen ovale diameter in normal fetuses, suggesting that the modifications of its diastolic displacement is not influenced by the size of the interatrial opening.

A mobilidade do Septum primum não depende do diâmetro do forame oval em fetos normais / Mobility of the Septum primum does not depend on the foramen ovale diameter in normal fetuses

OBJETIVO: Testar a hipótese de que existe correlação entre o diâmetro máximo diastólico do forame oval e o índice de excursão do septum primum em fetos normais. MÉTODOS: Foram examinados, por ecocardiografia, 102 fetos normais de gestantes com idades gestacionais entre 20 e 40 semanas. O diâmetro do forame oval e a excursão máxima do septum primum foram medidos num corte de 4 câmaras. Na análise dos dados utilizou-se o coeficiente de correlação de Pearson. RESULTADOS: A média do forame oval foi de 5,06 ± 1,29 mm; a da excursão máxima do septum primum de 5,42 ± 1,41 mm; a do átrio esquerdo 11,47 ± 2,76 mm e a do índice de excursão 0,48 ± 0,09. A relação média FO/IE foi de 11,35 ± 3,94 mm. Não houve correlação FO/IE (r = -0,03) e observou-se correlação fraca do forame oval com o átrio esquerdo (r = 0,031) e com a excursão do septum primum (r = 0,21). CONCLUSAO: A mobilidade do septum primum não depende do diâmetro do forame oval em fetos normais, sugerindo que as modificações da sua excursão diastólica não decorram do grau de abertura interatrial.

Behavior of septum primum mobility in third-trimester fetuses with myocardial hypertrophy.

OBJECTIVES: The mobility of the septum primum (SP) in the fetus is a diastolic phenomenon and could be related to left atrial pressure. We studied the linear displacement of the SP in the left atrium in fetuses of diabetic mothers (FDM) with and without septal hypertrophy (SH) and in normal fetuses of normoglycemic mothers. In this study we set out to test the hypothesis that the linear displacement of the SP flap valve is less marked in fetuses with SH than in those without SH. METHODS: The ratio between the linear displacement of the flap valve and the left atrial diameter (excursion index (EI)) was compared in ten FDM with SH, eight FDM with normal septal thickness and eight normal fetuses of non-diabetic mothers. Atrioventricular flow velocities were also compared in the three groups. RESULTS: Comparison of the three groups showed that in FDM with SH, the mean EI was 0.36 +/- 0.09, in FDM without SH it was 0.51 +/- 0.09 (P = 0.001) and in the control fetuses it was 0.49 +/- 0.12 (P = 0.03). There was a significant negative correlation between septal thickness and EI in FDM with SH. There was no correlation between septal thickness and atrioventricular flow velocities. CONCLUSION: Mobility of the SP in FDM with SH is reduced and there is an inverse correlation between the linear displacement of the SP and septal thickness. These findings may be related to changes in left ventricular diastolic function secondary to myocardial hypertrophy.

Association of pulmonary atresia with intact ventricular septum and aortic valve stenosis. Prenatal diagnosis.

A rare association of pulmonary atresia with an intact septum was diagnosed through echocardiography in a fetus 32 weeks of gestational age. The diagnosis was later confirmed by echocardiography of the newborn infant and further on autopsy. The aortic valve was bicuspid with a pressure gradient of 81 mmHg, and the right ventricle was hypoplastic, as were the pulmonary trunk and arteries, and the blood flow was totally dependent on the ductus arteriosus.

Myocardial interatrial septum loses its epithelial organization by mesenchymal influence. Structural and ultrastructural study.

During atrial septation, the septum primum fuses with the atrioventricular endocardial cushions and myocardial-mesenchymal interactions occur. In order to evaluate the cellular events that take place during this particular interaction a structural, ultrastructural and histochemical study was performed. Our findings indicate that from the fourth day of development, the distal myocardium of the interatrial septum, which interacts with mesenchymal tissue, loses its appearance of an epithelial sheet and becomes a loosely organized tissue. The distal myocytes of the interatrial septum which get progressively separated show features of migratory cells, the final localization of which is the mesenchymal tissue of the adjacent endocardial cushions. These tissue changes involve basal membrane disruption, reduction in the number of desmosomes and intercalated discs with the subsequent appearance of large intercellular spaces between myocytes, myofibrillar disarrangement and acquisition by myocytes of a secretory phenotype characterized by numerous cytoplasmic vesicles. These events occur in a similar way in the atrioventricular canal, where a myocardial-mesenchymal interaction also occurs. In both regions the mesenchymal endocardial cushions and its associated extracellular matrix seem to direct the dissociation of the myocardial tissue and the subsequent migratory cellular behaviour of the interacting myocytes. This is an interesting, and little known, example of a cellular phenotypic transformation during cardiac development.

Development of the pars membranacea septi interventricularis of the human heart. II. Thickness change.

The measurement of the thickness of the pars membranacea septi interventricularis of the human heart increases with the intra-uterine age of the fetus along a steep, ascending, straight line. The thickening of the PMSI occurs in phase I of the development from 0.246 mm (CR = 16.8 mm) to 0.524 mm (CR = 119 mm) and in phase II from 0.601 mm (CR = 149 mm) to 1.024 mm (CR = 362 mm). The thickness increases, then, from the ending of the closure of the secondary interventricular foramen to the end of the fetal period.

[The pathological remnants of the right sinus venosus valve. A presentation of 6 hearts of the cor tritriatum dexter type]. / Derivados patológicos de la valva derecha del seno venoso. Presentación de seis corazones de tipo cor triatriatum dextrum.

Six hearts specimens of cor triatriatum dextrum, eight with the Chiari's network, and 3 with a membranous remnant of the crista terminalis are studied. These anomalies are interpreted as varying degrees of persistence of the right valve of the sinus venous which reflect different stages of their morphogenesis. The most frequent congenital heart defects associated with these sinus remnants are the absence of a right atrioventricular connexion and pulmonary atresia with intact ventricular septum. There may be some haemodynamic factors in the right atrium such as partial of complete obstruction between the atrium and the right ventricle which explain the fact that the valve is not reabsorbed. In our specimens the persistent right valve divided the right atrium into two compartments; one is located in the medial sinusal portion where both cavae veins and coronary sinus are connected; the other is lateral compartment which represents the primitive right atrium. It must be noted that the persistent right valve favors blood flow to the left atrium through the patent foramen ovale or through an atrial septal defect deviating the course of the blood away from the right ventricle. This could cause the hypoplasia of the right ventricle. When the valve bulges it obstructs the blood flowing into the right ventricle. The diagnosis of these malformations can be made by echocardiographic, angiocardiographic procedures and nuclear magnetic resonance.

Development of the pars membranacea septi interventricularis of the human heart. I. Collagen fibers, fixed connective cells and amorphous fundamental substance.

The development of the pars membranacea septi interventricularis of the human heart, from the closure of the secondary interventricular foramen to the end of the fetal age, presents two phases well separated by a period of transition between the 119 mm long (CR) fetus, corresponding to 15.1 weeks, and the 149 mm long (CR) fetus, corresponding to 17.1 weeks. In the I phase, 78% the fixed connective cells and 22% of the amorphous fundamental substance were replaced by bundles of collagen fibers. In the II phase, 75% of the amorphous fundamental substance and 25% of the fixed connective cells were replaced by bundles of collagen fibers.

[Embryologic and anatomic considerations on normal and pathologic heart separation. II. Atrioventricular and interventricular septum]. / Consideraciones embriológicas y anatómicas sobre la septación cardiaca normal y patológica. II. Septum atrioventricular e interventricular.

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.

Consideraciones embriológicas y anatómicas sobre la septación cardiaca normal y patológica: II. Septum atrioventricular e interventricular / Embriologycal and anatomycal conciderations on normal and pathological cardiac septation. II atrioventricular and interventricular septa (AU)

Se define el septum atrioventricular y sus características anatomicas. Este septum se divide en dos regiones: muscular y membranosa. Se describen los tipos de comunciación atrioventricular aisladas. Se discute la embriogénesis normal y patológica del septum atrioventricular. Se define el septum interventricular y se describen sus características anatómicas. Este septum se divide en dos regiones: fibrosa y muscular. La muscular se divide en tres regiones: porción de la cámara de salida o infundibular (outlet). Las comunicaciones inteventriculares se clasifican de acuerdo con las regiones septales en que están ubicadas. Se establecen las características anatómicas de identidad de cada una de ellas. Se hace un breve comentario sobre la morfogénesis normal y patológica del septum interventricular. Septum atrioventricular; septum interventricular

[Embryologic and anatomic considerations on the normal and pathologic formation of the cardiac septum. I. Interauricular septum]. / Consideraciones embriológicas y anatómicas sobre la septación cardiaca normal y patológica. I. Septum interauricular.

A brief presentation of the normal embryological development of the human interatrial septum is made. The anatomical expression of each of its embryological components is described. Our classification of interatrial septal defect is enriched by their more precise anatomical description and by making a more correct morphogenetic interpretation, based on new information obtained by means of experimental embryology. Emphasis is made that absence of the interatrial septum does not preclude the diagnosis of viscero-atrial situs.

[The P loop in atrioventricular septal defect. Embryologico-vectorcardiographic correlation]. / El asa P en el defecto del septum atrio-ventricular. Correlación embriológico-vectocardiográfia.

Atrial vectorcardiograms (vcg) were analysed in 23 patients with partial (n = 15) or complete (n = 8) forms of atrioventricular septal defect (AVSD). The rotation and the projection of the maximum left atrial vector (MLAV) on the frontal plane (FP) and on the horizontal plane (HP) were noted. To assess the possible influence of the degree of left-to-right shunting and the right atrial and right ventricular pressures on the rotation and MLAV projection, these vcg data were correlated with hemodynamic values obtained at the time of preoperative cardiac catheterization. Vcg characteristics of the patients were also compared with those of 25 healthy individuals. No significant differences were noted between the vcg of patients with the partial form and those with the complete form of AVSD. Also, there was no apparent influence of the hemodynamic values on the loop rotation or the MLAV projection in either plane among the patients. However, the MLAV showed a more posteriorly and superior location in the FP and HP than in normal subjects (p = 0.0001). Moreover, 67% of the cases showed a clockwise rotation of the loop in the HP and 33% in the FP; in contrast, normal subjects always showed a counterclockwise rotation in both planes. A more posterior and superior MLAV is consistent with direct observations in human embryos with AVSD which have shown that deficiencies of the posterior portion of the interventricular septum are the basic feature in all cases. The adaptation of the conductive tissue to such deficiency occurs in early phases of cardiac development.