Document Detail

Arrhythmogenesis in the developing heart during anoxia-reoxygenation and hypothermia-rewarming: an in vitro model.
MedLine Citation:
PMID:  17014683     Owner:  NLM     Status:  MEDLINE    
INTRODUCTION: The spatio-temporal pattern of arrhythmias in the embryonic/fetal heart subjected to a transient hypoxic or hypothermic stress remains to be established. METHODS AND RESULTS: Spontaneously beating hearts or isolated atria, ventricles, and conotruncus from 4-day-old chick embryos were subjected in vitro to 30-minute anoxia and 60-minute reoxygenation. Hearts were also submitted to 30-minute hypothermia (0-4 degrees C) and 60-minute rewarming. ECG disturbances and alterations of atrial and ventricular electromechanical delay (EMD) were systematically investigated. Baseline functional parameters were stable during at least 2 hours. Anoxia induced tachycardia, followed by bradycardia, atrial ectopy, first-, second-, and third-degree atrio-ventricular blocks and, finally, transient electromechanical arrest after 6.8 minutes, interquartile ranges (IQR) 3.1-16.2 (n = 8). Reoxygenation triggered also Wenckebach phenomenon and ventricular escape beats. At the onset of reoxygenation QT, PR, and ventricular EMD increased by 68%, 70%, and 250%, respectively, whereas atrial EMD was not altered. No fibrillations, no ventricular ectopic beats, and no electromechanical dissociation were observed. Arrhythmic activity of the isolated atria persisted throughout anoxia and upon reoxygenation, whereas activity of the isolated ventricles abruptly ceased after 5 minutes of anoxia and resumed after 5 minutes of reoxygenation. During hypothermia-rewarming, cardiac activity stopped at 17.9 degrees C, IQR 16.2-20.6 (n = 4) and resumed at the same temperature with no arrhythmias. All preparations fully recovered after 40 minutes of reoxygenation or rewarming. CONCLUSION: In the embryonic heart, arrhythmias mainly originated in the sinoatrial tissue and resembled those observed in the adult heart. Furthermore, oxygen readmission was by far more arrhythmogenic than rewarming and the chronotropic, dromotropic, and inotropic effects were fully reversible.
Alexandre Sarre; Philippe Maury; Pavel Kucera; Lukas Kappenberger; Eric Raddatz
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Publication Detail:
Type:  In Vitro; Journal Article     Date:  2006-09-29
Journal Detail:
Title:  Journal of cardiovascular electrophysiology     Volume:  17     ISSN:  1540-8167     ISO Abbreviation:  J. Cardiovasc. Electrophysiol.     Publication Date:  2006 Dec 
Date Detail:
Created Date:  2007-01-22     Completed Date:  2007-02-21     Revised Date:  2007-11-15    
Medline Journal Info:
Nlm Unique ID:  9010756     Medline TA:  J Cardiovasc Electrophysiol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  1350-9     Citation Subset:  IM    
Department of Physiology, Faculty of Biology and Medicine, Hospital University, Lausanne, Switzerland.
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MeSH Terms
Anoxia / complications,  physiopathology*,  therapy
Arrhythmias, Cardiac / embryology*,  physiopathology*
Chick Embryo
Disease Models, Animal
Heart / embryology*,  physiopathology*
Heart Conduction System / embryology,  physiopathology
Hypothermia / complications,  physiopathology*,  therapy
Oxygen / therapeutic use*
Rewarming / methods*
Reg. No./Substance:
Comment In:
J Cardiovasc Electrophysiol. 2006 Dec;17(12):1360-1   [PMID:  17034406 ]

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