二重波の再入力は,心室性タヒカルディアの加速のメカニズムである
J Brugada1, L Boersma, C Kirchhof
1Department of Physiology, University of Limburg, Maastricht, The Netherlands.
Circulation
|May 1, 1990
まとめ
ウサギの心臓で持続した心室性短拍が誘発され,研究されました. 2つの波が同時に循環する現象である二重波再入は,心拍脈加速の原因として特定され,薬物効果にも影響を及ぼしています.
科学分野:
- 心血管生理学 心血管の生理学
- 電気生理学 電気生理学
- 心律不整症とは,心律不整症のこと.
背景:
- Ventricular tachycardia (VT) は,生命を脅かす不律性である.
- VTのメカニズム,特にリエントラント回路の理解は,効果的な治療法の開発に不可欠です.
- 電気的性質の方向性による依存である心筋離性 (アニソトロピー) は,再侵入波の伝播に影響を与えます.
研究 の 目的:
- インビトロモデルで持続的なリエントラント静脈性短心症のメカニズムを調査する.
- 二重波再入りの現象と,心拍脈加速におけるその役割を探求する.
- ダブルウェーブ再侵入誘導に対する抗リズム薬の影響を評価する.
主な方法:
- プログラムされた電気刺激を用いて,ランゲンドルフが浸透したウサギの心室内膜環で持続した心室内鼓動脈の誘導.
- リエントラント回路のダイナミクスを分析するために,256の単極電極図を用いた連続した表心臓マッピング.
- 心筋繊維の方向との関係における波の伝播速度 (縦対横) の評価.
- クラスIIIおよびクラスIC抗不律薬による二重波再侵入誘導およびその調節の評価.
主要な成果:
- 持続的な再侵入性VTは,168 ± 13msecのサイクルの長さで確実に誘導されました.
- タキカルディアは,固定された障害物の周りのリエントラント回路に基づいており,アニソトロプ的伝播 (ゆっくり横方向,速く縦方向) がある.
- 6/26の実験では二重波の再入力が観察され,高動脈加速を引き起こした.
- ダブルウェーブ再侵入は,あるケースではクラスIIIの薬剤によって阻害され,別のケースではクラスICの薬剤によって促進された.
- 二重波の再入力を用いたタキカルディアは,単一波の再入力を用いたタキカルディアと比較して,より長いサイクルの長さ (197 ± 11 msec) と,より大きな興奮可能なギャップ (71 ± 16 msec) を示した.
結論:
- ダブルウェーブ再入力は,プログラムされた電気刺激中に心室性短動脈の加速のためのメカニズムです.
- 心筋のアニゾトロプ的性質は,再侵入波の伝播を調節する上で重要な役割を果たします.
- ダブルウェーブ再侵入は,前動脈不良薬の効果と急性心室性タキハルジアの病理生理学を理解するための潜在的な臨床的意味合いを持っています.
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