Document Detail

Haemodynamic and energetic properties of stunned myocardium in rabbit hearts.
MedLine Citation:
PMID:  8624873     Owner:  NLM     Status:  MEDLINE    
OBJECTIVE: To amplify the description of myocardial stunning. DESIGN: Control versus 30 min after a 20 min no flow ischaemia. EXPERIMENTAL ANIMALS: 15 isolated rabbit hearts perfused with erythrocyte suspension. MAIN OUTCOME MEASURES: Left ventricular systolic function in terms of aortic flow, peak systolic pressure (LVPmax), dP/dtmax, and the end systolic pressure-volume relation (ESPVR); early relaxation from dP/dtmin and rate of left ventricular pressure decay (tau). Passive properties: ventricular and myocardial stiffness. Coronary resistance from coronary blood flow and perfusion pressure. Total myocardial oxygen consumption (MVo2tot). Total mechanical energy via pressure-volume area (PVA). Contractile efficiency (Econ) and MVo2 of the unloaded contracting heart (MVo2unl). External mechanical efficiency (Eext) from stroke work and MVo2tot. RESULTS: Systolic variables in stunned myocardium were significantly decreased (mean (SD)): aortic flow: 38 (13) v 9 (11) ml/min; LVPmax: 112 (19) v 74 (18) mm Hg; dP/dtmax: 1475 (400) v 1075 (275) mm Hg/s. ESPVR was not significantly decreased, at 138 (73) v 125 (58) mm Hg/ml, but the volume axis intercept was shifted rightward: 0.30 (0.37) v 0.65 (0.25) ml. Likewise, early relaxation was impaired: dP/dtmin (-1275 (250) v -975 (250) mm Hg/s) and tau (37 (7) v 46 (10) ms). LVPed was significantly decreased at 19 (12) v 12 (7) mm Hg, and both the ventricular (end diastolic pressure-volume relation) and the myocardial stiffness (constant k) were increased by 75% and 31%, respectively. Coronary resistance increased non-significantly from 0.83 (0.31) to 1.04 (0.41) mm Hg/(ml/min/100 g). Decreases in PVA (570 (280) v 270 (200) mm g), MVo2tot (40 (9) v 34 (8) microliters/beat/100 g), and MVo2unl (26 (9) v 22 (6) microliters/beat/100 g) did not reach significance, in contrast to significant decreases in Econ (31 (18) v 14 (7)%) and Eext (0.75 (0.29) v 0.18 (0.25) arbitrary units). CONCLUSIONS: Ventricular systolic function is decreased after brief episodes of ischaemia. The decrease in diastolic function probably amplifies the systolic deterioration during myocardial stunning. Passive diastolic properties are also changed, shown by increases in both ventricular and myocardial stiffness. The increase in coronary resistance indicates stunning at the vascular level which could limit oxygen supply. With maintained MVo2tot during stunning, external efficiency is decreased. Possible candidates for this metabolic stunning are inadequate excitation-contraction coupling and disturbed O2 utilisation by the contractile apparatus.
J D Schipke; B Korbmacher; A Dorszewski; G Selcan; U Sunderdiek; G Arnold
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Heart (British Cardiac Society)     Volume:  75     ISSN:  1355-6037     ISO Abbreviation:  Heart     Publication Date:  1996 Jan 
Date Detail:
Created Date:  1996-06-25     Completed Date:  1996-06-25     Revised Date:  2010-03-24    
Medline Journal Info:
Nlm Unique ID:  9602087     Medline TA:  Heart     Country:  ENGLAND    
Other Details:
Languages:  eng     Pagination:  55-61     Citation Subset:  AIM; IM    
Institute of Experimental Surgery, Heinrich-Heine-University D?sseldorf, Germany.
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MeSH Terms
Coronary Circulation
Energy Metabolism / physiology*
Heart / physiopathology*
Hemodynamics / physiology
Myocardial Contraction / physiology
Myocardial Stunning / metabolism,  physiopathology*
Oxygen Consumption / physiology
Vascular Resistance / physiology
Ventricular Function, Left / physiology

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