2004 Fiscal Year Final Research Report Summary
Quantitative analysis of the arterial baroreflex transient response during acute myocardial infarction toward optimized therapy
| Project/Area Number |
15590786
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Circulatory organs internal medicine
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| Research Institution | National Cardiovascular Center Research Institute |
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Principal Investigator |
KAWADA Toru National Cardiovascular Center Research Institute, Department of Cardiovascular Dynamics, Laboratory Chief, 循環動態機能部, 室長 (30243752)
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| Co-Investigator(Kenkyū-buntansha) |
UEMURA Kazunori National Cardiovascular Center Research Institute, Department of Cardiovascular Dynamics, Research Staff, 循環動態機能部, 室員 (10344350)
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| Project Period (FY) |
2003 – 2004
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| Keywords | acute myocardial infarction / arterial baroreflex / transfer function / equilibrium diagram / coronary occlusion / sympathetic nerve activity / circulatory model / circulatory control |
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| Research Abstract |
The present study was designed to quantitatively analyze the effects of acute myocardial infarction on the cardiovascular regulation and to develop a circulatory model capable of describing hemodynamic changes during acute myocardial infarction. By using this model, hemodynamic changes during acute myocardial infarction may be described quantitatively in terms of changes in model parameters. Such a quantitative evaluation would contribute to a risk stratification of acute myocardial infarction. In addition, the prediction of the circulatory responses to drug administrations would lead to the optimized drug administrations with tide minimum total amount of drug used. In the present study, we quantified the dynamic and static characteristics of the arterial baroreflex by a transfer function analysis and an equilibrium diagram analysis, respectively. In anesthetized rabbits, activation of the vagally-mediated cardiac reflex by phenylbiguanide approximately halved the arterial baroreflex g
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ain calculated from changes in sympathetic nerve activity relative to the pressure changes. We designed an automated drug infusion system by taking into account the predicted changes in the baroreflex gain. When a classical proportional-integrative-derivative(PID) controller with fixed parameter values was used, changes in the magnitude of biological responses to a given amount of drug makes the circulatory regulation unstable. In contrast, an adaptive predictive controller with a neural network provided a stable circulatory regulation regardless of changes in the biological responses to a given amount of drug. Although the effects of acute coronary occlusion on the arterial baroreflex were examined, changes in the dynamic characteristics were not significant even when hypotension with pump failure manifested. Possible explanation for the absence of significant effects of coronary occlusion on the baroreflex gain might be an absence of vagally-mediated cardiac reflex due to vagal withdrawal under anesthetic conditions. Less
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