Document Detail


Short-term hypertension is associated with the development of atrial fibrillation substrate: a study in an ovine hypertensive model.
MedLine Citation:
PMID:  20185115     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
BACKGROUND: Hypertension is frequently complicated by the development of atrial fibrillation (AF). However, the mechanisms of this link remain poorly understood. In addition, whether short-term hypertension can result in a substrate for AF is not known. OBJECTIVE: The purpose of this study was to characterize the atrial substrate predisposing to AF due to short-duration hypertension. METHODS: Sixteen sheep were studied: 10 had induced hypertension for 7 +/- 4 weeks via the "one-kidney, one-clip" model, and six were controls. Cardiac magnetic resonance imaging was used to assess functional changes. Open-chest electrophysiological study was performed using a custom-made 128-electrode epicardial plaque applied to both right (RA) and left atria (LA), including the Bachmann's bundle, to determine effective refractory periods (ERPs) and conduction velocity at four pacing cycle lengths from six sites. Tissue specimens were harvested for structural analysis. RESULTS: The hypertensive group demonstrated the following compared with controls: higher blood pressure (P <.0001), enlarged LA (P <.05), reduced LA ejection fraction (P <.05), uniformly higher mean ERP (P <.001), slower mean conduction velocity (P <.001), higher conduction heterogeneity index (P <.0001), greater AF inducibility (P = .03), and increased AF durations (P = .04). Picrosirius red staining of atrial tissues revealed increased interstitial fibrosis (P <.0001). There was also evidence of increased inflammatory cell infiltrates (P <.0001). CONCLUSION: Short-duration hypertension is associated with significant atrial remodeling characterized by atrial enlargement/dysfunction, interstitial fibrosis, inflammation, slowed/heterogeneous conduction, increased ERP, and greater propensity for AF.
Authors:
Dennis H Lau; Lorraine Mackenzie; Darren J Kelly; Peter J Psaltis; Michael Worthington; Arumuga Rajendram; Douglas R Kelly; Adam J Nelson; Yuan Zhang; Pawel Kuklik; Anthony G Brooks; Stephen G Worthley; Randall J Faull; Mohan Rao; James Edwards; David A Saint; Prashanthan Sanders
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2009-12-02
Journal Detail:
Title:  Heart rhythm : the official journal of the Heart Rhythm Society     Volume:  7     ISSN:  1556-3871     ISO Abbreviation:  Heart Rhythm     Publication Date:  2010 Mar 
Date Detail:
Created Date:  2010-02-26     Completed Date:  2010-06-01     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  101200317     Medline TA:  Heart Rhythm     Country:  United States    
Other Details:
Languages:  eng     Pagination:  396-404     Citation Subset:  IM    
Copyright Information:
Copyright 2010 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.
Affiliation:
Cardiovascular Research Centre, Department of Cardiology, Royal Adelaide Hospital, Adelaide, Australia.
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MeSH Terms
Descriptor/Qualifier:
Animals
Atrial Fibrillation / etiology,  metabolism,  physiopathology*
Disease Models, Animal
Hypertension / complications,  physiopathology*
Models, Cardiovascular
Sheep
Time Factors

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