Structure, function and clinical relevance of the cardiac conduction system, including the atrioventricular ring and outflow tract tissues

The rhythmic contraction of the vertebrate heart is dependent on organized propagation of electrical excitation through the cardiac conduction system. Because both muscle- and neuron-specific genes are co-expressed in cells forming myocardial conduction tissues, two origins, myogenic and neural, have been suggested for this specialized tissue. Using replication-defective retroviruses, encoding recombinant beta-galactosidase (beta-gal), we have analyzed cell lineage for Purkinje fibers (i.e., the peripheral elements of the conduction system) in the chick heart. Functioning myocyte progenitors were virally tagged at embryonic day 3 of incubation (E3). Clonal beta-gal+ populations of cells, derived from myocytes infected at E3 were examined at 14 (E14) and 18 (E18) days of embryonic incubation. Here, we report that a subset of clonally related myocytes differentiates into conductile Purkinje fibers, invariably in close spatial association with forming coronary arterial blood vessels. These beta-gal+ myogenic clones, containing both working myocytes and Purkinje fibers, did not incorporate cells contributing to tissues of the central conduction system (e.g. atrioventricular ring and bundles). In quantitative analyses, we found that whereas the number of beta-gal+ myocyte nuclei per clone more than doubled between E14 and E18, the number of beta-gal+ Purkinje fiber nuclei remained constant.(ABSTRACT TRUNCATED AT 250 WORDS)

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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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