Document Detail

Effects of reperfusion on ischemic right ventricular dysfunction. Disparate mechanisms of benefit related to duration of ischemia.
MedLine Citation:
PMID:  8087950     Owner:  NLM     Status:  MEDLINE    
BACKGROUND: Right ventricular free wall (RVFW) ischemia impairs global RV performance and may result in acute hemodynamic compromise. However, RV function and hemodynamic performance typically improve spontaneously over time. This study was designed to determine whether reperfusion facilitates recovery of function in the ischemic right ventricle. METHODS AND RESULTS: Closed chest dogs underwent right coronary balloon occlusion for 1 hour (n = 9), 4 hours (n = 6), or 8 hours (n = 7). In all animals, occlusion depressed RVFW function and global RV performance. After 1 hour of ischemia, reperfusion led to immediate improvement in RVFW function and consequently global RV performance, with complete recovery over 4 weeks and scar in < 1% of total RVFW area. Reperfusion after 4- and 8-hour occlusions resulted in acute improvement in global RV performance but to a lesser extent and by different mechanisms, since RVFW contraction remained severely impaired. This disproportionate recovery of global RV function was attributable to diminished RVFW dyskinesis associated with reperfusion-induced increments in RVFW diastolic thickness (characterized histopathologically in 6 additional animals subjected to 4-hour occlusions but killed 1 hour after reperfusion by interstitial edema, contraction band necrosis, and hemorrhage). Although later reperfusion was associated with a slower pace and lesser extent of recovery, RVFW contraction improved markedly over time. At 4 weeks, there was trivial RVFW scar in 4-hour animals (2% of total RVFW area), and, although fibrosis was significantly greater in 8-hour animals (7% of RVFW area), infarction was minimal relative to the extent of jeopardized myocardium. CONCLUSIONS: The responses of ischemic RV myocardium to reperfusion are complex, with disparate effects according to the duration of preceding ischemia. Early reperfusion results in prompt improvement in and subsequent complete recovery of RVFW contraction and global RV performance, with trivial or no RVFW scar. Late reperfusion leads to little acute recovery of RVFW function, but global performance improves owing to diminished RVFW dyskinesis associated with reperfusion-induced increments in RVFW diastolic thickness. Nevertheless, RVFW function improves over time, with minimal evidence of infarction. Therefore, reperfusion facilitates recovery of RV function and minimizes the extent of infarction even after prolonged ischemia.
S B Laster; Y Ohnishi; J E Saffitz; J A Goldstein
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  Circulation     Volume:  90     ISSN:  0009-7322     ISO Abbreviation:  Circulation     Publication Date:  1994 Sep 
Date Detail:
Created Date:  1994-10-18     Completed Date:  1994-10-18     Revised Date:  2007-11-14    
Medline Journal Info:
Nlm Unique ID:  0147763     Medline TA:  Circulation     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  1398-409     Citation Subset:  AIM; IM    
Department of Medicine, Washington University School of Medicine, St Louis, Mo. 63110.
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MeSH Terms
Acute Disease
Arterial Occlusive Diseases / pathology,  physiopathology,  ultrasonography
Coronary Disease / pathology,  physiopathology,  ultrasonography
Myocardial Ischemia / physiopathology*
Myocardial Reperfusion*
Myocardium / pathology
Time Factors
Ventricular Function, Right*
Grant Support

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

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