1989 Fiscal Year Final Research Report Summary
Basic research for cardiac assistance with an electrically transformed skeletal muscle
| Project/Area Number |
62440055
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| Research Category |
Grant-in-Aid for General Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Research Field |
Thoracic surgery
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| Research Institution | Jikei University School of Medicine |
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Principal Investigator |
HORIKOSHI Shigeki Jikey University Cardiac Surgery Assistant Professor, 心臓外科, 助教授 (90056987)
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| Co-Investigator(Kenkyū-buntansha) |
MORITA Kiyozo Jikei University Cardiac Surgery Assistant, 心臓外科, 助手 (70174422)
SASAKI Tatsuumi Jikei University Cardiac Surgery Instructor, 心臓外科, 講師 (20138754)
SUGITA Youichi Jikei University Cardiac Surgery Instructor, 心臓外科, 講師 (40130174)
SUZUKI Shigeru Jikei University Cardiac Surgery Instructor, 心臓外科, 講師 (50130175)
ARAI Tatsuta Jikei University Cardiac Surgery Professor, 心臓外科, 教授 (60056471)
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| Project Period (FY) |
1987 – 1989
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| Keywords | Latissimus Dorsi / Electrical Preconditioning / Skeletal Muscle / Myocardial Replacement / Cardiac Assistance / Transformation / Dynamic Patch |
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| Research Abstract |
Following studies were performed to evaluate the possibility of autologous skeletal muscle grafts to augment left ventricular function in adult mongrel dogs. 1.Contractile capacity of revascularized free latissimus dorsi muscle grafts Contractile property of skeletal muscle ventricles constructed with electrically preconditioned latissimus dorsi was evaluated by the test circuit simulating left heart circulation. Results demonstrated that electrical preconditioning reduced muscle fatigue accompanied with transformation of muscle fiber type and improvement of muscle metabolism. And the optimum stimulus for cardiac assistance by skeletal muscle grafts was revealed to be a high frequency trained-pulse ( 25Hz). 2.Assistance and replacement of myocardium with revascularized free muscle grafts:
Free latissimus dorsi muscles preconditioned for as long as 2 weeks, were revascularized with the internal mammary artery and the right atrial appendage and sutured to ischemic areas of the left ventricular walls which had been produced by legation of the left anterior descending coronary artery. The effect of synchronously paced latissimus dorsi grafts on regional myocardial performance was evaluated by using sonomicrometry. Results showed that a revascularized free latissimus dorsi graft has the ability to contract in systole against left ventricular wall stress under normal left ventricular end-diastolic pressure, and to argument regional left ventricular performance in dyskinetic segments. Furthermore left ventricular myocardium was partially rejected and replaced with a latissimus dorsi graft under an extra corporeal circulation. The left ventricular pressure and cardiac output increased significantly with graft contraction at a frequency of 50 Hz.
So it was concluded that revascularized free latissimus dorsi grafts could be used as a dynamic patch in reconstructive cardiac surgery for myocardial defect.
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