Document Detail

Electrocardiogram changes during positive pressure breathing in rabbits.
MedLine Citation:
PMID:  8861669     Owner:  NLM     Status:  MEDLINE    
Positive pressure breathing produced by mechanical ventilation with an expiratory threshold load (ETL) may modify electrocardiogram (ECG) complexes independently of any recording artefact due to lung volume changes. Anaesthetized, paralyzed rabbits were treated for about 2 h, then killed. In intact then vagotomized animals two situations were studied successively. Firstly, positive inspiratory pressure breathing, and secondly, positive inspiratory plus expiratory pressure breathing by adding ETL to mechanical ventilation. Arterial blood gases were measured and held constant throughout the challenge. Oesophageal pressure, giving indirect measurement of intrathoracic pressure, arterial blood pressure, blood flows in abdominal aorta and inferior vena cava and standard ECG recordings were made at baseline condition during mechanical ventilation, then at the end of a 10-min period of ETL breathing. The ETL breathing decreased arterial blood pressure significantly and reduced arterial and venous blood flows in the same proportion. No change in the duration of ECG complexes was noticed. However, ETL markedly reduced the amplitude of P- and T-waves, but not that of R-wave, an effect significantly accentuated after vagotomy. The ETL breathing increased the T-vector angle, with no associated change in QRS vector angle. The present animal investigations revealed that positive pressure breathing modifies the ECG independently of the consequences of ETL-induced lung volume changes. We speculate that the changes in P- and T-wave amplitude may have resulted from a reduced transmural pressure gradient between the epicardium and endocardium.
F Joulia; P Barthelemy; V Lafay; M C Zattara-Hartmann; Y Jammes
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  European journal of applied physiology and occupational physiology     Volume:  73     ISSN:  0301-5548     ISO Abbreviation:  Eur J Appl Physiol Occup Physiol     Publication Date:  1996  
Date Detail:
Created Date:  1997-05-27     Completed Date:  1997-05-27     Revised Date:  2007-11-15    
Medline Journal Info:
Nlm Unique ID:  0410266     Medline TA:  Eur J Appl Physiol Occup Physiol     Country:  GERMANY    
Other Details:
Languages:  eng     Pagination:  56-60     Citation Subset:  IM    
Laboratoire de Physiopathologie Respiratoire Intégree et Cellulaire (URA 1630 CNRS) Institut Jean Roche, Marseille, France.
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MeSH Terms
Differential Threshold
Positive-Pressure Respiration*

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