Atresia of the pulmonary artery with intact intraventricular septum

Cardiological studies of 16 patients with atresia of the pulmonary artery (APA) and intact interventricular septum (IIS) provided evidence for the following inferences: 1) most hearts in this pathology are characterized by right ventricular (RV) hypoplasia which determines structural defects of the ventricle dependent in their severity on restriction capacity of the right atrioventricular valve and time from the onset of reduced RV blood flow 2) common anatomical features of the defect are complete RV obstruction due to valvular atresia, IIS and normal shape of the conus, RV myocardial hypertrophy 3) survival of the patients conditioned by interatrial communication and open arterial canal. According to the authors, there are three types of APA with IIS. Type I--normal right ventricle with distinct components: sinuous, conical, trabecular. Type II--hypoplastic right ventricle with blocked function of the trabecular component. Type III--right ventricle affected by advanced hypoplasia and with operable sinuous part only.     

Mesenchymal tissue of the interventricular septum

Summary Light and electron microscopic studies of frontal and sagittal sections of embryonic chick hearts (Stages 25, 28–29), reveal mesenchymal tissue in the cephalic portion of the interventricular septum. The endocardium of this cephalic portion contains reoriented and invaginated cells with pseudopodia; in addition there are cells immediately subjacent to the endocardium. Similar cellular events take place during the formation of mesenchymal tissue in the atrioventricular and conotruncal regions. In these regions the mesenchymal tissue originates by means of an endocardial activation process.The structural characteristics of the formation of the cephalic portion of the interventricular septum suggest that local mesenchymal tissue is contributed by the endocardium. However, based upon the close anatomic relationship observed by us between the mesenchymal tissues of the atrioventricular canal, conotruncal region and the cephalic portion of the interventricular septum; we do not discard a contribution by migration of cells from atrioventricular and conotruncal regions to the interventricular septum.     

Symptomatic lipoma in the interventricular septum

Cardiac lipomas, which are benign nonmyxomatous neoplasms of the heart, are rare and among those least often encountered. Because they normally cause no symptoms, diagnosis is often purely accidental. We report the case of a 24-year-old woman who presented with palpitations of recent onset and was found to have a lipoma attached to the left side of the interventricular septum (IVS). Transthoracic and transesophageal echocardiograms were performed and showed a mass in the left side of the IVS. During successful surgical excision of the mass, intraoperative histologic diagnosis showed the tumor was lipoma. Our review of the English literature revealed that our case is only the seventh of removal of lipoma in the IVS. The postoperative course was uneventful, and an echocardiogram taken 6 months after the operation showed no evidence of enlargement of the tumor tissue.     

室间隔膜部的应用解剖学研究

目的阐明成年人心室间隔膜部的形态、位置、毗邻关系,为医学影像诊断提供形态学基础。方法成年人离体心脏64例,大体解剖观察室间隔膜部的形态、位置、毗邻结构。胸部断层标本观察室间隔膜部的原位解剖学特征。结果离体心室间隔膜部:①形态可见不规则形、三角形、半月形、圆形、卵圆形、四边形和楔形。②左侧面位于主动脉前半月瓣环和右后半月瓣环相对缘与肌性室间隔嵴之间,上缘紧邻主动脉前半月瓣环和右后半月瓣环及其瓣间三角;右侧面位于三尖瓣前内侧连合处,房室隔最前端,与三尖瓣前内侧连合、室上嵴、主动脉隆凸、Koch三角尖端和右纤维三角相邻。经四心腔横断层,MPIS占室间隔的后1/3,自左前斜向右后与矢状面、冠状面约呈45°角;经升主动脉冠状断层,MPIS自肌性室间隔嵴斜向右上方达主动脉半月瓣环的下方,与正中矢状面呈45°角。结论MPIS形态多样,左、右侧面的位置和毗邻各异;横断层和冠状断层能很好地显示MPIS的形态、位置和毗邻关系。     

The membranous part of the human interventricular cardiac septum

The arrangement of collagen and elastic fibers of the membranous part of the interventricular septum (PMS) was studied in hearts from adult humans. Connective bundles formed a network of fairly independent tendons arranged in two layers. The tendinous bundles consisted essentially of type I collagen fibers while type III fibers were visible as a thin network with transversely and longitudinally oriented meshes around the muscle bundles. Cranial and caudal to the PMS were narrow and irregular bands of collagen fibers that apparently represented zones of low resistance to the high blood pressures acting from the left to the right heart chambers. The predominance of fiber bundles arranged in an approximately transverse direction with regard to the arterial cone axis suggests a resistance to enlargement resulting from high aortic blood pressure. Elastic fibers were observed in the transitional zone between the cardiac muscle and the PMS. They were continuous with elaunin fibers and these with oxytalan fibers closely intermingled with the narrow network of type I collagen fibers of the PMS. The successive transformation of elastic fibers, which were very numerous in the muscle-tendon transition, into elaunin and these into oxytalan fibers toward the central portions of the PMS suggests a functional sequence characterized by a high elasticity and consequent mobility of the transition region itself and by a progressive increase of resistance in this portion.     

Pulmonary atresia with intact ventricular septum and hypoplastic right heart in sibs: a single gene disorder?

We report on 2 sisters with hypoplastic right heart and pulmonary atresia. The first sib was found to have pulmonary atresia, intact ventricular septum, and hypoplastic right heart after delivery. Fetal echocardiography at 22 weeks of gestation during the second pregnancy documented the same cardiac abnormalities. Autopsy findings in the fetus confirmed the echocardiographic findings. No other malformations were detected in either case, and no other affected relatives were identified. We suggest that this rare congenital heart defect may, in some cases, be an autosomal recessive trait.     

Familial occurrence of pulmonary atresia with intact ventricular septum

Pulmonary atresia with intact ventricular septum (PA/IVS) is a rare disease, accounting for less than 3% of all congenital heart lesions. The cause of PA/IVS is unknown. We report the occurrence of two first cousins with PA/IVS, suggestive of autosomal dominant inheritance with incomplete penetrance. The study of such families should ultimately lead to the identification of the gene(s) that cause congenital heart disease. Am. J. Med. Genet. 72:294–296, 1997. © 1997 Wiley-Liss, Inc.     

Morphological changes of interventricular septum in long-term follow-up cases]

In patients who could be followed by echocardiography for a long period, the clinical significance of sigmoid septum and basal septal hypertrophy including long-term changes was investigated in patients with hypertension. The subjects were 66 patients (24 males and 42 females, mean age: 53 +/- 12 years old) who underwent repeated echocardiography, and the initial examination and observation after long-term follow-up (mean duration of follow-up: 10.8 +/- 1.4 years) were compared. Sigmoid septum was more advanced at the time of initial examination in the hypertensive group than in the normotensive group, but it was similarly advanced after the long-term follow-up in both groups. There was no significant difference in basal septal hypertrophy between the hypertensive and normotensive groups at the time of initial examination, but significant increases in thickening were observed in the hypertensive group after the long-term follow-up. The above findings suggested that morphological changes in the interventricular septum reflect the severity of arteriosclerosis that is expected to be more advanced in hypertensive patients than in normotensive patients.