心筋リラクゼーション:イソボリュメトリックリラクゼーションの時間経過に対するプレロードの影響
Circulation
|May 1, 1986
まとめ
プリロードの単一の増加は,心筋のリラックスに影響を与えない. 犬とネズミの研究では,プレロードの変化だけでは,イソヴォルメトリックまたはイソメトリックのリラックス時間の経過を変更しないことが示されています.
科学分野:
- 心臓病学 心臓病学
- 生理学 生理学とは
背景:
- 効率的な心臓機能には,心臓のリラックスが不可欠です.
- 収縮前の心筋の伸縮であるプレロードは,心臓のパフォーマンスの重要な決定因子です.
研究 の 目的:
- 心臓のリラックスに対するプレロードの独立した効果を調査する.
- リラクゼーションダイナミクスに対するプレロードと他の負荷条件の影響を区別する.
主な方法:
- 麻酔を施された犬を用いたインビボ試験では,変化したプレロードで,イソヴォルメトリックのリラックス時間定数 (T) を測定した.
- 単離されたラットおよび犬の心筋製剤を用いたインビトロ研究で,異なるプレロード条件下での同位体リラクゼーションを評価した.
主要な成果:
- 完ぺきな犬の心臓では,プリロードの単一の増加は,リラックス時間常数 (T) の有意な増加につながった.
- しかし,左心室内静脈圧が一定に保たれた場合,プレロードの変化はT.に影響しませんでした.
- 孤立した筋肉製剤では,総負荷を一定に保ったとき,イソメトリックリラクゼーションはプレロードとは無関係であった.
結論:
- プリロードの孤立した増加は,無傷の心臓における同体体量度リラクゼーションの時間経過に影響しません.
- 心筋のリラクゼーションは,他の負荷状態が制御されている場合,プレロード以外の要因に主に依存します.
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