Cardiac conduction system in the chicken: Gross anatomy plus light and electron microscopy

More than 100 years after the discovery of the sinus node (SN) by Keith and Flack, the function and structure of the SN have not been completely established yet. The anatomic architecture of the SN has often been described as devoid of an organized structure; the origin of the sinus impulse is still a matter of debate, and a definite description of the long postulated internodal specialized tract conducting the impulse from the SN to the atrioventricular node (AVN) is still missing. In our previously published study, we proposed a morphologically ordered structure for the SN. As a confirmation of what was presented then, we have added the results of additional observations regarding the structural particularities of the SN. We investigated the morphology of the sinus node in the human hearts of healthy individuals using histochemical, immunohistochemical, optical, and electron microscopy (SEM, TEM). Our results confirmed that the SN presents a previously unseen highly organized architecture.

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Distribution and Structure of Purkinje Fibers in the Heart of Ostrich (Struthio camelus) with the Special References on the Ultrastructure

International Journal of Zoology ◽

10.1155/2013/293643 ◽

2013 ◽

Vol 2013 ◽

pp. 1-6 ◽

Cited By ~ 2

Author(s):

Paria Parto ◽

Mina Tadjalli ◽

S. Reza Ghazi ◽

Mohammad Ali Salamat

Keyword(s):

Light And Electron Microscopy ◽

Great Part ◽

Conduction System ◽

Point Of View ◽

Cardiac Conduction ◽

Cardiac Conduction System ◽

Purkinje Fibers ◽

Thin Ring ◽

T Tubules ◽

P Cells

Purkinje fibers or Purkinje cardiomyocytes are part of the whole complex of the cardiac conduction system, which is today classified as specific heart muscle tissue responsible for the generation of the heart impulses. From the point of view of their distribution, structure and ultrastructural composition of the cardiac conduction system in the ostrich heart were studied by light and electron microscopy. These cells were distributed in cardiac conducting system including SA node, AV node, His bundle and branches as well as endocardium, pericardium, myocardium around the coronary arteries, moderator bands, white fibrous sheet in right atrium, and left septal attachment of AV valve. The great part of the Purkinje fiber is composed of clear, structure less sarcoplasm, and the myofibrils tend to be confined to a thin ring around the periphery of the cells. They have one or more large nuclei centrally located within the fiber. Ultrastructurally, they are easily distinguished. The main distinction feature is the lack of electron density and having a light appearance, due to the absence of organized myofibrils. P-cells usually have two nuclei with a mass of short, delicate microfilaments scattered randomly in the cytoplasm; they contain short sarcomeres and myofibrillar insertion plaque. They do not have T-tubules.

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Dobutamine on the Cardiac Conduction System

Case Medical Research ◽

10.31525/ct1-nct04249258 ◽

2020 ◽

Author(s):

Keyword(s):

Conduction System ◽

Cardiac Conduction ◽

Cardiac Conduction System

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Faculty Opinions recommendation of TBX5 drives Scn5a expression to regulate cardiac conduction system function.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.717952867.793458352 ◽

2012 ◽

Author(s):

Céline Fiset ◽

Nabil El Khoury

Keyword(s):

Conduction System ◽

Cardiac Conduction ◽

Cardiac Conduction System ◽

System Function

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Molecular Profiling of the Cardiac Conduction System: the Dawn of a New Era

Current Cardiology Reports ◽

10.1007/s11886-021-01536-w ◽

2021 ◽

Vol 23 (8) ◽

Author(s):

Sruthi Mantri ◽

Sean M. Wu ◽

William R. Goodyer

Keyword(s):

Molecular Profiling ◽

Conduction System ◽

Cardiac Conduction ◽

Cardiac Conduction System ◽

New Era

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Sudden Unexpected Death Associated with Arrhythmogenic Cardiomyopathy: Study of the Cardiac Conduction System

Diagnostics ◽

10.3390/diagnostics11081323 ◽

2021 ◽

Vol 11 (8) ◽

pp. 1323

Author(s):

Giulia Ottaviani ◽

Graziella Alfonsi ◽

Simone G. Ramos ◽

L. Maximilian Buja

Keyword(s):

Fibromuscular Dysplasia ◽

Ventricular Myocardium ◽

Conduction System ◽

Cardiac Conduction ◽

Future Research ◽

Cardiac Conduction System ◽

Arrhythmogenic Cardiomyopathy ◽

Unexpected Death ◽

The Past ◽

The Right

A retrospective study was conducted on pathologically diagnosed arrhythmogenic cardiomyopathy (ACM) from consecutive cases over the past 34 years (n = 1109). The anatomo-pathological analyses were performed on 23 hearts diagnosed as ACM (2.07%) from a series of 1109 suspected cases, while histopathological data of cardiac conduction system (CCS) were available for 15 out of 23 cases. The CCS was removed in two blocks, containing the following structures: Sino-atrial node (SAN), atrio-ventricular junction (AVJ) including the atrio-ventricular node (AVN), the His bundle (HB), the bifurcation (BIF), the left bundle branch (LBB) and the right bundle branch (RBB). The ACM cases consisted of 20 (86.96%) sudden unexpected cardiac death (SUCD) and 3 (13.04%) native explanted hearts; 16 (69.56%) were males and 7 (30.44%) were females, ranging in age from 5 to 65 (mean age ± SD, 36.13 ± 16.06) years. The following anomalies of the CCS, displayed as percentages of the 15 ACM SUCD cases in which the CCS has been fully analyzed, have been detected: Hypoplasia of SAN (80%) and/or AVJ (86.67%) due to fatty-fibrous involvement, AVJ dispersion and/or septation (46.67%), central fibrous body (CFB) hypoplasia (33.33%), fibromuscular dysplasia of SAN (20%) and/or AVN (26.67%) arteries, hemorrhage and infarct-like lesions of CCS (13.33%), islands of conduction tissue in CFB (13.33%), Mahaim fibers (13.33%), LBB block by fibrosis (13.33%), AVN tongue (13.33%), HB duplicity (6.67%%), CFB cartilaginous meta-hyperplasia (6.67%), and right sided HB (6.67%). Arrhythmias are the hallmark of ACM, not only from the fatty-fibrous disruption of the ventricular myocardium that accounts for reentrant ventricular tachycardia, but also from the fatty-fibrous involvement of CCS itself. Future research should focus on application of these knowledge on CCS anomalies to be added to diagnostic criteria or at least to be useful to detect the patients with higher sudden death risks.

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