Document Detail

The extent of the specialized atrioventricular ring tissues.
MedLine Citation:
PMID:  19328044     Owner:  NLM     Status:  MEDLINE    
BACKGROUND: The so-called specialized tissues within the heart are the sinus node, the atrioventricular conduction system, and the Purkinje network. Further structures with the characteristics of specialized tissue are also found within the atrioventricular junction, although they are less well described. OBJECTIVE: The purpose of this study was to demonstrate the location and extent of these atrioventricular ring specialized tissues, showing their relationship with the normal atrioventricular conduction system. METHODS: We identified the tissues using histology combined with immunohistochemical labeling with connexin43 (Cx43), the major gap junction in heart, and HCN4, the major isoform of the funny channel. RESULTS: We observed rings of specialized tissue mainly in hearts from rats, mice, and guinea pigs, negative for Cx43 but positive for HCN4. Each ring takes its origin from an inferior extension of the atrioventricular node. The rightward ring runs around the vestibule of the tricuspid valve, whereas the leftward ring encircles the mitral valve. On returning toward the atrial septum, the tricuspid ring crosses over the penetrating part of the atrioventricular conduction system, reuniting with the mitral ring to form a superiorly located retroaortic node. The atrioventricular conduction system itself continues beyond the origin of the right and left bundle branches, forming an aortic ring that ascends toward the retroaortic node but fails to make contact because of the intervening area of aortic-to-mitral valvar fibrous continuity. CONCLUSION: Rings of conduction tissue take their origin from inferior extensions of the atrioventricular node, passing rightward and leftward to encircle the orifices of the tricuspid and mitral valves and reuniting to form an extensive retroaortic node. Thus, a ring with morphologic features justifying a definition of specialized conduction tissue surrounds the atrioventricular junctions, although its function has yet to be established.
Joseph Yanni; Mark R Boyett; Robert H Anderson; Halina Dobrzynski
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Publication Detail:
Type:  Comparative Study; Journal Article; Research Support, Non-U.S. Gov't     Date:  2009-01-21
Journal Detail:
Title:  Heart rhythm : the official journal of the Heart Rhythm Society     Volume:  6     ISSN:  1556-3871     ISO Abbreviation:  Heart Rhythm     Publication Date:  2009 May 
Date Detail:
Created Date:  2009-04-24     Completed Date:  2009-08-25     Revised Date:  2009-10-27    
Medline Journal Info:
Nlm Unique ID:  101200317     Medline TA:  Heart Rhythm     Country:  United States    
Other Details:
Languages:  eng     Pagination:  672-80     Citation Subset:  IM    
Cardiovascular Research Group, Faculty of Medical and Human Sciences, University of Manchester, United Kingdom.
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MeSH Terms
Aorta, Thoracic / cytology,  innervation*,  metabolism
Atrioventricular Node / cytology*,  metabolism
Bundle of His / cytology*,  metabolism
Caveolin 3 / metabolism
Cell Size
Connexin 43 / metabolism
Cyclic Nucleotide-Gated Cation Channels / metabolism
Guinea Pigs
Potassium Channels / metabolism
Rats, Wistar
Grant Support
//British Heart Foundation
Reg. No./Substance:
0/Caveolin 3; 0/Connexin 43; 0/Cyclic Nucleotide-Gated Cation Channels; 0/HCN3 protein, mouse; 0/HCN4 protein, rat; 0/Potassium Channels
Comment In:
Heart Rhythm. 2009 May;6(5):681-3   [PMID:  19389654 ]

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