1995 Fiscal Year Final Research Report Summary
Mechanical energetics in patients with left ventricular hypertrophy and/or dysfunction
| Project/Area Number |
06670706
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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 | Nagoya University |
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Principal Investigator |
YOKOTA Mitsuhiro Nagoya University, School of Medicin Associate Professor, 医学部, 助教授 (50201851)
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| Co-Investigator(Kenkyū-buntansha) |
SOBUE Toshikazu Nagoya University, School of Medicin Clinical Fellow, 医学部, 医員
HIRAI Makoto Nagoya University, School of Medicin Instructor, 医学部, 助手 (90242875)
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| Project Period (FY) |
1994 – 1995
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| Keywords | Dilated Cardiomyopathy / Myocardial Energetics / Left Ventricular Pressure-volume Relations / Inotropic Agents / Ventriculoarterial Coupling / Myocardial Oxygen Consumption / Mechanical Efficiency |
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| Research Abstract |
Idiopathic dilated cardiomyopathy is a fetal heart disease that severely compromises cardiac performance. One problem is that this disease is extremely resistant to therapy and no inotropic agent has been reported to decrease its mortality. Various aspects of this disease including the pathophysiology, hemodynemics have been analyzed and reported, but this study have focused on how these variable affect myocardial energetics. By means of left ventricular pressure-volume relations, we investigated left ventricular contractility, arterial loading conditions and the way their interaction affects myocardial energetics in patients with idiopathic dilated cardiomyopathy. The effects fo 3 inotropic agents including dobutamine, MS-857 and OPC-18790 with different mechanism of action were investigated. A phosphodiesterase inhibitor MS-857 and OPC-18790 works mainly by inhibiting phosphodiesterase, and OPC-18790 prolongs the action potential of myocyte.
Methods. Pressure-volume data were measured in 33 patients with idiopathic dilated cardiomyopathy by using a conductance catheter, and myocardial oxygen consumption was obtained simultaneously by a double-themistor coronary sinus catheter (Wilton-Webster Laboratories). Fogarty catheter was placed in the inferior vena cava and was inflated transiently for the determination of left ventricular pressure-volume relation.
Conclusions. The degree of ventriculoarterial coupling is far from optimal and the cardiovascular performance is severely depressed mechanically and energetically in patients with indiopathic dilated cardiomyopathy. Althought inotropic agents improve the coupling and increased the work efficiency, but not enough to optimize the coupling condition. It appears that myocardial oxygen utilization is regulated to maintain a constant mechanical efficiency.
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