Document Detail

'And the beat goes on.' The cardiac conduction system: the wiring system of the heart.
MedLine Citation:
PMID:  19592411     Owner:  NLM     Status:  MEDLINE    
The cardiac conduction system (CCS), consisting of the sino-atrial node, atrioventricular node and His-Purkinje system, is responsible for the initiation and co-ordination of the heart beat. In the last decade, our understanding of the CCS has been transformed. Immunohistochemistry, used in conjunction with anatomical techniques, has transformed our understanding of its anatomy; arguably, we now understand the position of the sino-atrial node (not the same as in medical textbooks), and our new understanding of the atrioventricular node anatomy means that we can compute its physiological and pathophysiological behaviour. Ion channel expression in the CCS has been shown to be fundamentally different from that in the working myocardium. Dysfunction of the CCS has previously been attributed to fibrosis, but it is now clear that remodelling of ion channels plays an important role in dysfunction during ageing, heart failure and atrial fibrillation. Differences in ion channel expression may even be responsible for the bradycardia in the athlete and differences in heart rate among different species (such as humans and mice). Recent work has highlighted less well-known components of the CCS, including tricuspid, mitral and aortic rings and even a third (retro-aortic) node. These additional tissues do not participate in the initiation and co-ordination of the heart beat and instead they are likely to be the source of various life-threatening arrhythmias. During embryological development, all parts of the CCS have been shown to develop from the primary myocardium of the linear heart tube, partly under the influence of the transcription factor, Tbx3.
Mark R Boyett
Publication Detail:
Type:  Journal Article; Review     Date:  2009-07-10
Journal Detail:
Title:  Experimental physiology     Volume:  94     ISSN:  1469-445X     ISO Abbreviation:  Exp. Physiol.     Publication Date:  2009 Oct 
Date Detail:
Created Date:  2009-09-25     Completed Date:  2009-12-07     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  9002940     Medline TA:  Exp Physiol     Country:  England    
Other Details:
Languages:  eng     Pagination:  1035-49     Citation Subset:  IM    
Cardiovascular Medicine, School of Medicine, University of Manchester, Core Technology Facility, 46 Grafton Street, Manchester M13 9NT, UK.
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MeSH Terms
Action Potentials / physiology
Gene Expression / physiology
Heart / anatomy & histology,  physiology*
Heart Conduction System / anatomy & histology,  physiology*
Ion Channels / physiology
Pacemaker, Artificial
Sinoatrial Node / physiology
Reg. No./Substance:
0/Ion Channels

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