Document Detail

Three-dimensional mapping of right atrial activation during sinus rhythm and its relationship to endocardial architecture.
MedLine Citation:
PMID:  12475108     Owner:  NLM     Status:  MEDLINE    
INTRODUCTION: Previous mapping studies of right atrial (RA) activation during sinus rhythm have been limited by the use of epicardial electrode plaques in open chest subjects or microelectrodes in the excised heart. This study describes global RA endocardial activation patterns using high-density mapping and compares the results with underlying endocardial architecture. METHODS AND RESULTS: Noncontact mapping of the RA was performed in 21 anesthetized swine. Isopotential and isochronal maps were superimposed upon three-dimensional reconstructions of RA geometry. Hearts were excised and endocardial dissection performed. Two patterns of RA activation were recorded. The site of earliest endocardial activation occurred either laterally at a position consistent with the terminal crest or superiorly at the junction between the superior caval vein and RA appendage. The subsequent spread of depolarization followed the longitudinal orientation of muscle fibers. Areas of conduction delay and block were seen at the junction between the terminal crest and posterior wall, the cavotricuspid isthmus, and around the margins of the triangle of Koch. Endocardial dissection at these sites demonstrated complex fiber orientation. A lateral site of earliest activation demonstrated a more prominent display of conduction delay or block. CONCLUSION: The spread of the sinus impulse follows endocardial myofiber orientation and is dictated by the site of earliest activation. Even during sinus rhythm, anisotropic conduction results in areas of conduction block or delay. These findings have implications in the development of reentrant arrhythmias and may influence surgical or electrophysiologic procedures.
Tim R Betts; Siew Yen Ho; Damian Sanchez-Quintana; Paul R Roberts; Robert H Anderson; John M Morgan
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Journal of cardiovascular electrophysiology     Volume:  13     ISSN:  1045-3873     ISO Abbreviation:  J. Cardiovasc. Electrophysiol.     Publication Date:  2002 Nov 
Date Detail:
Created Date:  2002-12-11     Completed Date:  2003-03-18     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  9010756     Medline TA:  J Cardiovasc Electrophysiol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  1152-9     Citation Subset:  IM    
Southampton University Hospitals, United Kingdom.
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MeSH Terms
Endocardium / anatomy & histology*,  physiology*
Heart / physiology*
Heart Atria
Heart Rate*
Neural Conduction
Sinoatrial Node / physiology*
Time Factors

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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