1989 Fiscal Year Final Research Report Summary
Influence of Preload, Afterload and Cardiotonic Drugs on Left Ventricular Asynergy.
| Project/Area Number |
62570378
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
Circulatory organs internal medicine
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| Research Institution | Akita University |
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Principal Investigator |
KANAZAWA Tomohiro Akita University Sch. of Med. The 2nd Dept. of Int. Med. Professor, 医学部, 教授 (90004762)
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| Co-Investigator(Kenkyū-buntansha) |
TAJIKA Takehiko Akita University Sch. of Med. The 2nd Dept. of Int. Med. Assistant, 医学部, 助手 (80171718)
MATUOKA Hitoshi Akita University Sch. of Med. The 2nd Dept. of Int. Med. Assistant Professor, 医学部, 講師 (60181707)
KOBAYASHI Masao Akita University Sch. of Med. Dept. of Laboratory Med. Assistant, 医学部, 助手 (70178333)
MIURA Mamoru Akita University Sch. of Med. The 2nd Dept. of Int. Med. Associate Professor, 医学部, 助教授 (10006710)
IKEDA Shigeaki Akita University Sch. of Med. The 2nd Dept. of Int. Med. Assistant Professor, 医学部, 講師 (40125703)
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| Project Period (FY) |
1987 – 1989
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| Keywords | REGIONAL LEFT VENTRICULAR ASYNERGY / PROCAINE INTRACORONARY INFUSION / PRELOAD・AFTERLOAD / SYSTOLIC CORONARY BLOOD FLOW / MYOCARDIAL OXYGEN CONSUMPTION(MVO_2) / LUXURY PERFUSION / DISSOCIATION OF MVO_2 & CONTRACTION / STUNNED MYOCARDIUM |
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| Research Abstract |
Regional left ventricular asynergy produced by intracoronary infusion of procaine was studied in relation to preload and afterload. Further, coronary circulation and myocardial oxygen consumption in the area of asynergy was studied.
In anesthetized open-chest dogs, the left anterior descending coronary artery(LAD) was perfused from the carotid artery via a bypass. Procaine (4%) was infused into the bypass to produce akinesis or dyskinesis. Regional wall motion was assessed with two pairs of microcrystals in LAD and circumflex(CX) area. Coronary blood flow was measured with an electromagnetic flowmeter installed in the bypass. Arterial and anterior interventricular coronary venous bloods were served for gas analysis and determination of regional myocardial oxygen consumption(MVO_2). Preload was increased by elevating a reservoir connected to the left atrium Afterload mas increased by constricting proximal descending aorta.
Preload increased %systolic shortening(%SS)in CX , caused no chang
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e of asynergy in LAD and improved left ventricular function, i.e. increase of stroke volume and maxdp/dt. Afterload worsened asynergy in LAD, did not change %SS in CX and depressed left ventricular function. From these results,it is concluded that in treatment of acuteavocardial infarct ion, preload should be kept at appropriate level and cardiotonic drugs causing less increase of afterload should be used.
The ratio of systolic coronary blood flow to diastolic in LAD increased during procaine infusion and correlated inversely with %SS in LAD. This indicates that loss of systolic compression to the coronary artery increased systolic coronary blood flow.
Regional MVO_2 in LAD did not show significant changes during procaine infusion in spite of marked depression of myocardial contraction. This dissociation of MVO_2 and myocardial contractility is very similar to the dissociation of MVO_2 and myocardial contractility in stunned myocardium^<1)>. The mechanism of depressing myocardial contractility in this study is the inhibition of electrical excitation, while the mechanism in stunned myocardium has not been elucidated. However, these pathophysiological states are the same in the point that coronary blood flow was supplied in excess to the myocardium whose contractility was depressed, i.e. luxury perfusion. Thus, the luxury perfusion is suggested to cause the dissociation of MVO_2 and myocardial contractility in this study. Less
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Research Products
(9 results)
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[Publications] Awaji,T.,Ikeda,S.,Tate,H.,Kanazawa,A.,Ishikawa,K.,Maki,K.,Kousokabe,H.,Kanazawa,T.,et.al.: "Reversible left ventricular asynergy by intracoronry infusion of procaine." Automedia. 9. 68 (1987)
Description
「研究成果報告書概要(和文)」より
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