| Project/Area Number |
04670927
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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 |
麻酔学
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| Research Institution | Okayama University Medical School |
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Principal Investigator |
TOKIOKA Hiroaki Okayama Univ.Med.Sch., Associate Professor, 医学部・附属病院, 助教授 (90127572)
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| Co-Investigator(Kenkyū-buntansha) |
SUGA Hiroyuki Okayama Univ.Med.Sch., Professor, 医学部, 教授 (90014117)
HIRAKAWA Masahisa Okayama Univ.Med.Sch., Professor, 医学部, 教授 (70033058)
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| Project Period (FY) |
1992 – 1993
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| Project Status |
Completed (Fiscal Year 1993)
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| Budget Amount *help |
¥2,100,000 (Direct Cost: ¥2,100,000)
Fiscal Year 1993: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1992: ¥1,600,000 (Direct Cost: ¥1,600,000)
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| Keywords | PVA (pressure-volume area) / VO2 (myocardial oxygen consumption) / ventricular fibrillation / ePVA (equivalent PVA) / eHR (equivalent heart rate) / e'PVA / エネルギー効率 |
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| Research Abstract |
PVA (pressure-volume area) proposed by H.Suga (co-investigator) is the specific area surrounded by the end-systolic and end-diastolic pressure-volume relations and the systolic pressure-volume trajectory in the pressure-volume diagram and serves as a primary determinant of myocardial oxygen consumption (VO2) of a contracting ventricle. PVA has been shown to represent the total mechanical energy generated by each contraction of the ventricle, and VO2 per beat is highly linearly correlated with PVA.In this project, we have proposed a new mechanical index, equivalent pressure-volume area (ePVA), as a measure of the total mechanical energy generated by single contractions of all individual myocytes in a fibrillating ventricle based on the multicompartment model, utilizing the PVA concept. ePVA is an analog of PVA of a contracting ventricle and the area surrounded by the horizontal pressure-volume line at the pressure of ventricular fibrillation (VF) and the end-systolic pressure-volume relations in the beating state in the pressure-volume diagram. In the isolated blood perfused dog heart preparation, ePVA at various left ventricular volumes was highly linearly correlated with VO2 obtained during VF.We also determined equivalent heart rate (eHR) as an estimate of the contraction frequency of individual myocytes in VF from mechanically unloaded VO2 in beating and fibrillating states. Using both ePVA and eHR, VO2 during VF was estimated and correlated with directly measured VO2. This ePVA-eHR-VO2 relationship was acceptable regardless of the contractile state and the heart temperature. We concluded that ePVA is a primary determinant of VO2 during VF, and that VO2 of a fibrillating ventricle can be reasonably accounted for by the combination of ePVA and eHR.
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