心室Purkinje纤维传导系统的自动生成算法

由于Purkinje纤维在心脏心室中的复杂分布,它的仿真成为心电正问题研究中的一个难点。本文利用分形树结构来描述Purkinje纤维传导系统,提出了满足边界条件的分形树生长算法,通过对心内膜擘的球映射,该算法能在心室壁上自动生成Purkinje纤维分形树,不需要人工干预。     

心室传导系统解剖模型中心肌激动的计算机仿真

本文介绍一种以解剖为基础的心室传导系统电传播的计算机仿真方法。模型由33000个单元组成,每一单元表示一根浦肯野纤维或房室结组织。采用Na~+的Ebihala-Johnson模型描述膜的动作特性并将这种新的建模方法与已有的一些方法联合使用,则在IBM3090机上完成心肌兴奋性的仿真大约需用5分钟的CPU时间。本文将模拟的激动时间与在心内心室肌的实验测量结果进行了比较。文献中所给的时间数值是从许多报导的人体心脏地形图的研究中得到的。开始的仿真结果与实验     

一种基于人体心室传导系统的解剖学结构模型

心室传导系统是一种特殊肌细胞的复杂网络,它担负着人体心脏房室间电活性的传导,它既是微观又是宏观层次上对生物电学与解剖学研究的焦点。对于心室激动的传导,由于它是最初的响应。因此,掌握两种层次的活动被认为是十分重要的。以前有关这方面的计算机模型是较为简单的,它主要是作为心室模型的从属物。本文介绍了一种传导系统结构的建立的思想及基于实际的微观与宏观特征。该模型较实体仍嫌简单。它包括35,000个独立的圆     

山羊心室条索的形态学特征

目的　观察山羊心室条索的解剖学和组织学特征。方法　对 82只成年山羊左右心室的游离条索进行解剖学观测 ,取 15例心脏的左心室 2 3条 ,右心室 17条条索 ,进行常规石蜡切片 ,HE和Masson染色 ,光镜下观察。结果　山羊左室条索的出现率为 95 12 % ,右心室出现率为 80 4 9% ,右心室条索的出现率明显低于左心室(P <0 .0 5 )。左心室条索以直条者较多 ,其次是一端和两端分叉型 ,少数呈网状。右心室条索的形态相对简单 ,网状和两端分叉型比较少见。左右心室条索直径大多小于 1mm。右室条索平均长 1 2 4± 0 5 0mm ,右心室长 0 93± 0 4 5mm ,98%的条索内含Pukinje细胞 ,2 %含心肌细胞。 结论　山羊左右心室腔内均存在游离条索 ,左心室多于右心室 ,条索内含有Pukinje细胞     

家兔房室交界区及其心房传导通路的形态学研究

目的：探讨射频消融改良房室交界区的形态学基础。方法：健康成年家兔10只，分别做房室交界区的额状面、矢状面及水平面连续切片，在HE、Masson及磷钨酸苏木素染色下观察其形态学特征。结果：家兔房室结位于房室隔内中心纤维体的右侧，主要由P细胞和T细胞组成，以P细胞为主，其向后形成的延伸部同射频消融慢径的部位吻合，且细胞分布明显较房室结稀疏，内有胶原纤维分隔。同时有四条过渡细胞带分别从心房的不同部位到达房室结及后延伸部，分别称为左房结束、右房结束、后房结束及上房结束。另外，在冠状窦前壁有P细胞成团分布。结论：①房室交界区的概念应当扩大，分布范围从房室隔内中心纤维体的右侧一直向后接近冠状窦口，前部可能为快传导区，后部可能为慢传导区。②房内传导通路确有存在，并且可能参与了房内折返性心律失常的形成。③冠状窦是一个重要的结外潜在起搏点，可能与某些房性自律性心律失常的发生有关。     

窦房结形态学研究进展

窦房结实质细胞起源于胚胎期窦房环或腔静脉窦壁中原始、未分化的特化心肌干细胞。结原基随胚胎发育可最终迁移至从腔耳角沿界嵴到下（后）腔静脉口范围内或仍存留上（前）腔静脉近侧段壁上。窦房结中央动脉管径粗大，可能起营养和功能血管双重作用。结中央无缝隙连结（缺Ｃｘ４３），边缘有少量缝隙连结（Ｃｘ４３阳性）。起搏Ｐ细胞主要位于结中央，其电镜结构最幼稚。Ｐ细胞周围丰富的胶原间质网架和过渡（Ｔ）细胞网架可能与生理起搏活动有密切关系。窦房结生后仍有继续发育、成熟、改建的过程     

一般内脏感觉传导径路的形态学研究

本文用HRP逆行追踪法,对大白鼠一般内脏感觉的中枢传导径路进行了初步探讨,提出了两条一般内脏感觉的中枢传导径路:即(1)NTS→外侧臂旁核→丘脑腹后内侧核→皮质10区;(2)NTS→外侧壁旁核→下丘禽外侧区丘脑腹后内侧核→皮质40区,以及内脏感觉传导径路的特点。进一步证明在大白鼠NTS与脊髓之间存在往返联系,认为NTS不仅是内脏感觉传导径路的中继站,而且是中枢神经系整合内脏功能的重要核团之一。本文用免疫细胞化学方法证明了在NTS内存在生长抑素和脑啡肽能神经细胞胞体及纤维,它们可能参与了内脏感觉的传导和内脏功能的整合。     

心室波形形态学用于四种新时域技术

通过植入式抗心搏过速装置以对顽固的心搏过程进行电控制,业已成为治疗方法中的一种重要形式。近来,最先进的心室性心搏过速探测方法建议:除了或者在进行早期以心率为基础的算法探测的同时,还应对心室内的电描记图形态学的变化进行观测。不幸的是,大多数所建议的形态学分析技术,除了在现有的装置要求之上,还要求要较高的计算能力。另外,它们还可能会由于心室内电描记图的幅值以及基线漂移而受到严重影响。我们设计了四种新的高计算有效性的时域算法。这些算法可将单形的心室性心搏过速(VT)期内的     

Attempt to visualise the ventricular conduction system intravitam

Summary A radiologic method for the visualisation of the left ventricular portion of the conducting system using cow, calf and sheep hearts which can be repeatedly reproduced in vitro is presented. The results of the experiments were documented by macro- and microphotograms.Critical analysis of a further in vivo study of this method is also discussed.

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Zusammenfassung Es wird eine röntgenologische, in vitro an Rinder-, Kälber- und Schafsherzen erprobte und beliebig oft reproduzierbare Methode zur Visualisation linksventrikulärer Anteile des Reizleitungssystems vorgestellt. Die Ergebnisse der Untersuchungen werden anhand von Makro- und Mikrophotogrammen dokumentiert.Zu der in einer weiteren Studie geplanten in vivo-Testung der Methode wird kritisch Stellung genommen.

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With support of Deutsche Forschungsgemeinschaft.     

Pathomorphology of the heart conduction system: comparative study during increase in left or right ventricular afterload

Pathomorphology of the peripheral compartments of the heart conduction system under conditions of increased left or right ventricular afterload is characterized by interstitial edema, hemorrhages, and reversible and irreversible focal lesions. The percentage of damaged conduction cardiomyocytes increases in the wall of hemodynamically overloaded ventricle and in the ventricular septum. These changes are more pronounced in cases when the afterload increase is complicated by heart failure development. Acute dilatation of the heart and distention of the myocardium are events of great specific significance in the genesis of the conduction system disorders developing under conditions of increased right ventricular afterload in comparison with those developing under conditions of increase left ventricular afterload. These data attest the presence of a pathomorphological base for the appearance of arrhythmias during the acute phase of pressure overload of the heart, especially in cases when it is aggravated by heart failure.     

Mesp1-nonexpressing cells contribute to the ventricular cardiac conduction system.

Previous fate mapping analysis, using Cre recombinase driven by the Mesp1 locus, revealed that Mesp1 is expressed in almost all of the precursors of the cardiovascular system, including the endothelium, endocardium, myocardium, and epicardium. Mesp1-nonexpressing cells were found to be restricted to the outflow tract cushion and along the interventricular septum (IVS), which is a location that is suggestive of specialized cardiac conduction system (CCS). In our current study, we examined the identity of these IVS cells by using the pattern of beta-galactosidase activity in CCS-lacZ mice. In addition, by crossing Mesp1-Cre and floxed GFP reporter mice with CCS-lacZ mice, we have calculated that approximately 20% of the ventricular CCS within the IVS corresponds to Mesp1-nonexpressing cells. These data suggest that the ventricular CCS is of heterocellular origin. Furthermore, we indicate a possibility that a population of the cells that contribute to the ventricular CCS might be distinguished at an early stage of development.     

Effect of ultrasound on the myocardium and cardiac conduction (A morphological study)

Focused ultrasound is used to create local foci of lesions in the myocardium. It is shown that this method can be used for the treatment of monofocal tachycardias. The effect of focused ultrasound on the myocardium, coronary artery, and atrioventricular node is studied in experiments on dogs, and the ultrasound-destroyed zones of the myocardium are investigated morphologically. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 118, N ^o 7, pp. 104–107, July, 1994 Presented by F. G. Uglov, Member of the Russian Academy of Medical Sciences     

Distribution of atrial natriuretic peptide in the conduction system and ventricular muscles of the human heart

Summary Atrial natriuretic peptide (ANP), a cardiac hormone, is known to be located in the atrial specific granules, but its presence and localization in the ventricular muscle of the human heart has not been examined fully. Using a specific antibody to human ANP, we studied the conduction system and ventricular muscle with immunohistochemical and ultrastructural methods in 30 hearts obtained at autopsy. These included 12 normal and 18 diseased hearts. In the normal hearts, ANP-positive granules, which were regularly observed in the atrial myocytes, were found in small quantities in the cells of the penetrating and branching bundles in 4 of 12, and in the cells of the ventricular free walls in 2 of the 12 hearts. In the diseased hearts, the positivity increased significantly (P<0.05), being found in 13 of 18 (72.2%) conduction systems and 10 of 18 (55.6%) ventricular muscles. The granules were confirmed to be immunoreactive with ANP by ultrastructural examination. Furthermore, the presence of ANP mRNA in the conduction system as well as in the ventricular myocytes was demonstrated by Northern blot hybridization for which we used the complementary DNA of human ANP. Thus, a small quantity of ANP appears to be synthesized and stored in the conduction system and ventricles of some normal hearts. However, ANP was shown to be present in a larger percentage of the diseased hearts.     

Effect of glialin on cardiac ventricular arrhythmias and myocardial conduction system in dogs

Intravenous glialin in a dose of 7 mg/kg suppressed the number of ectopic contractions caused by double ligature of the left coronary artery by the method of Harris and almost 2-fold prolonged animal life-span in comparison with the control. The maximum antiarrhythmic effect of glialin developed after 180 min and persisted for 5 h. Glialin injected intravenously (10 mg/kg) after myocardial infarction under conditions of programmed electrical stimulation inhibited conduction of evoked impulse in the atria, Purkinje fibers, and ventricular myocardium and did not modify the effective refractory periods of the atria and ventricles. __________ Translated from Byulleten’ Eksperimental’noi Biologii i Meditsiny, Vol. 143, No. 3, pp. 324–326, March, 2007