Document Detail


Myocardial protection in the failing heart: I. Effect of cardioplegia and the beating state under simulated left ventricular restoration.
MedLine Citation:
PMID:  17000300     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
OBJECTIVE: Heart failure was induced by cardiac pacing to evaluate myocardial flow distribution of the open ventricle during delivery of either cardioplegia or in the beating state during simulated left ventricular restoration. METHODS: Studies included 5 (pacing-induced) failing pig hearts and 6 control hearts. Pacing-induced cardiac failure reduced fractional shortening by approximately 22%, increased left ventricular end-diastolic diameter by 34%, caused pulmonary hypertension (mean blood pressure increased from 12 to 35 mm Hg), and led to significant ascites. Global and regional coronary blood flow were measured with microspheres during cardiopulmonary bypass at 80 mm Hg perfusion pressure in either vented (collapsed) or open (exposure by traction for left ventricular restoration) left ventricles during continuous perfusion under either beating-heart or cardioplegic conditions. RESULTS: In control hearts, venting and exposure ventriculotomy did not affect flow. In failing hearts decompressed by venting, coronary flow was lower during the beating and cardioplegic delivery than during control conditions at the same perfusion pressure of 80 mm Hg. Mean cardioplegic flow during ventricular decompression by venting exceeded beating flow by 97%. Conversely, traction to increase the ventricular radius during exposure ventriculotomy reduced endocardial cardioplegic coronary blood flow by 64% (from 0.97 to 0.59 mL/[min x g]), whereas the beating state raised endocardial flow by 95% (from 0.40 to 0.78 mL/[min x g]). Changing ventricular shape changed coronary vascular resistance in failing hearts during beating or cardioplegic delivery. CONCLUSIONS: Coronary blood flow alterations occurred only in failing hearts when geometry was changed from closed to open state. The beating method provided more endocardial flow than cardioplegic delivery during ventricular exposure for restoration. Vascular remodeling raised coronary vascular resistance in failing hearts, thereby requiring higher pressure for similar blood flows.
Authors:
Monica Kostelec; James Covell; Gerald D Buckberg; Ahmad Sadeghi; Julien I E Hoffman; Ghassan S Kassab
Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  The Journal of thoracic and cardiovascular surgery     Volume:  132     ISSN:  1097-685X     ISO Abbreviation:  J. Thorac. Cardiovasc. Surg.     Publication Date:  2006 Oct 
Date Detail:
Created Date:  2006-09-26     Completed Date:  2006-10-19     Revised Date:  2007-11-15    
Medline Journal Info:
Nlm Unique ID:  0376343     Medline TA:  J Thorac Cardiovasc Surg     Country:  United States    
Other Details:
Languages:  eng     Pagination:  875-83     Citation Subset:  AIM; IM    
Affiliation:
Department of Medicine, University of California, San Diego, Calif, USA.
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MeSH Terms
Descriptor/Qualifier:
Animals
Coronary Circulation
Heart Arrest, Induced*
Heart Failure / physiopathology,  surgery*
Heart Ventricles
Intraoperative Complications / physiopathology,  prevention & control
Swine
Grant Support
ID/Acronym/Agency:
2 R01 HL055554-06/HL/NHLBI NIH HHS

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


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