Document Detail

Effects of selectively produced changes in cardiac rhythm or conduction upon flow in the superior vena cava.
MedLine Citation:
PMID:  7278335     Owner:  NLM     Status:  MEDLINE    
The effects of changes in cardiac rhythm or conduction on the rate of volume flow in the superior vena cava (SVC) were studied in 25 dogs anesthetized with sodium pentobarbital. Slowing of sinus rate from 145 +/- 16 to 114 +/- 12 beats/min was achieved by selective perfusion of Ringer's solution into the sinus node artery. During sinus slowing there was a continuous change in the systolic-diastolic flow ratio measured in the SVC. At control sinus rate (net), total forward flow as 6.3 ml/beat with a systolic volume of 6.5 ml and a diastolic volume of -0.2 ml. At the slowest bradycardia, total forward flow had increased by 25%. Since there was no significant change in the systolic volume, the entire 25% increase in forward flow occurred during ventricular diastole. During atrioventricular (AV) block (second-degree or complete), achieved by selective perfusion of eserine into the AV node artery, unimpaired acceleration of flow was readily demonstrable in the SVC even in the absence of ventricular contraction. Thus systolic ventricular suction (vis a fronte) has little or no effect on right atrial filling. During high-degree AV block, the normal atrial contraction readily opened the tricuspid valve, and when both atrium and ventricle were filled to or near maximum capacity, atrial contraction was consistently vigorous enough to propel blood into the pulmonary artery. Given appropriate hemodynamic circumstances, these results confirm the remarkable effectiveness of right atrial contractile performance.
F Urthaler; H C Coghlan; T N James
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  The Journal of thoracic and cardiovascular surgery     Volume:  82     ISSN:  0022-5223     ISO Abbreviation:  J. Thorac. Cardiovasc. Surg.     Publication Date:  1981 Sep 
Date Detail:
Created Date:  1981-11-18     Completed Date:  1981-11-18     Revised Date:  2007-11-14    
Medline Journal Info:
Nlm Unique ID:  0376343     Medline TA:  J Thorac Cardiovasc Surg     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  447-56     Citation Subset:  AIM; IM    
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MeSH Terms
Atrioventricular Node / physiology*
Heart Block / physiopathology
Heart Conduction System / physiology*
Heart Rate
Myocardial Contraction*
Regional Blood Flow
Vena Cava, Superior / physiology*
Grant Support

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

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