| Project/Area Number |
04670819
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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 |
Thoracic surgery
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| Research Institution | NIIGATA UNIVERSITY |
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Principal Investigator |
WATAMABE Hiroshi Niigata University Scholl of Medicine, Assistant, 医学部・附属病院, 助手 (10240516)
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| Co-Investigator(Kenkyū-buntansha) |
TATEBE Shoh , 医員
SUGAWARA Masaaki Niigata University Scholl of Medicine, Clinical Fellow
菅原 正明 新潟大学, 医学部附属病院, 医員
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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 |
¥2,000,000 (Direct Cost: ¥2,000,000)
Fiscal Year 1993: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1992: ¥1,500,000 (Direct Cost: ¥1,500,000)
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| Keywords | Microwave / Arrhthmia Surgery / Transmural ablation |
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| Research Abstract |
The aim of this study was to develop a new technique of surgical ablation. We used a microwave tissue coagulator which emitted microwaves of 2,450 MHzin frequency. Microwave energy was applied to the ventricular myocardium via monopolar type needle electrode, 0.7mm in diameter and 1 cm in length. Studies were conducted on 22 mongrel dogs weighing between 9 and 13 kg and microwave tissue coagulation was performed at the free wall of left ventricle under the beating heart without cardiopulmonary bypass. The output power was 30 watts and 50 watts and the coagulation time varied from 10 to 60 seconds respectively. Microwave tissue coagulation created transmural degenerated lesion in both ventricles without risk of ventricular rupture. Prolongation of coagulation time resulted in significant incerase in diameter of coagulated area (Table). Histological examination revealed a well-demarcated area of heat degeneration consisted of coagulation necrosis and contraction band necrosis of myocardium. To estimate the long-term effects of microwave tissue coagulation, dogs were sacrificed at 1,3,7 and 14 days and at 1,3,6 and 13 months. For few days the lesion resembled a recent myocardial infarction with celluar infiltration of fibroblasts and luecocytes and healing by fibrosis with fatty infiltration was complete in 3 months. No animals had inducible ventricular tachycardia by programd ventricular stimulation. In conclusion, our results indicate that microwave tissue coagulation provides a new effective technique for arrhythmia surgery.
10seconds 20seconds 30seconds 60seconds
30 watts 6.00(〕SY.+-.〔)0.63 6.60(〕SY.+-.〔)0.49 10.83(〕SY.+-.〔)1.77 13.00(〕SY.+-.〔)1.67
50 watts 5.83(〕SY.+-.〔)0.69 9.40(〕SY.+-.〔)1.96 11.83(〕SY.+-.〔)1.46 15.83(〕SY.+-.〔)0.69
(mean(〕SY.+-.〔) standard deviation : mm)
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