2004 Fiscal Year Final Research Report Summary
A cardiopathological study on the anatomical substrate for fatal arrhythmias in aged companion animals
| Project/Area Number |
15580288
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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 |
Clinical veterinary science
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| Research Institution | National University Corporation Tokyo University of Agriculture and Technology |
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Principal Investigator |
MACHIDA Noboru National University Corporation Tokyo University of Agriculture and Technology, Institute of Symbiotic Science and Technology, Associate Professor, 大学院・共生科学技術研究部, 助教授 (20219364)
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| Co-Investigator(Kenkyū-buntansha) |
TANAKA Ryo National University Corporation Tokyo University of Agriculture and Technology, Institute of Symbiotic Science and Technology, Associate Professor, 大学院・共生科学技術研究部, 助教授 (70334480)
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| Project Period (FY) |
2003 – 2004
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| Keywords | Arrhythmia / Complete atrioventricular block / Conduction system / Bundle of His / Hypertrophic cardiomyopathy / Valvular endocardiosis / Cat / Dog |
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| Research Abstract |
The cardiac conduction system was histologically examined in 11 feline cases and 4 canine cases of complete atrioventricular block(CAVB) with the serial sectioning method and the following results and conclusions were obtained. In the cats with CAVB, underlying diseases included 9 cases of hypertrophic cardiomyopathy and each one case of mitral valve dysplasia and severe cardiac hypertrophy secondary to chronic interstitial nephritis. Histologically, a chondroid-or osseous-metaplastic lesion was seen in the lowermost portion of the fibrosed central fibrous body, protruding downward to the interventricular septal crest in each case. The lesion had compressed the penetrating portion and/or branching portion of the bundle of His, causing various degrees of degenerative changes and lysis and marked fibrosis of the bundle fibers. The marked fibrosis of the central fibrous body with cartilage or bone formation seems to occur as a result of stress and strain on the fibrous skeleton of the heart and may be due to mechanical factors created by hypertrophy of the interventricular septum. In all the 4 dogs with CAVB, gross anatomic changes associated with conduction system abnormalities included valvular endocardiosis of both atrioventricuar valves and endocardial fibrosis of the uppermost interventricular septum. Histologically, moderate to severe reduction of the conducting cells due to fibrous or fibro-fatty replacement was observed in some level in the penetrating and/or branching portions of the bundle of His in each case. In addition, 3 cases among the 4 had coexisting lesions at the proximal portions of the both bundle branches. This type of block in dogs was due to involvement of the conduction system in pathologic processes of the central fibrous body resulting from extension of myxomatous degeneration of both atrioventricular valves.
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Research Products
(4 results)
