心筋伸縮の電気生理学的効果と,伸縮によって活性化された不律律律の機械的決定因子
Circulation
|September 1, 1992
まとめ
漸進的ではなく,急速な心室伸縮は,膜の脱極化を引き起こし,不律を誘発する. この研究は,早発性心房刺激 (PVEs) を誘発する鍵としてストレッチの速度を強調し,ミトラル弁の転落のような状態でのエクトピーを説明する可能性がある.
科学分野:
- 心血管生理学 心血管の生理学
- 心臓電気生理学 心臓電気生理学
- アリトモゲネシス アリトモゲネシス
背景:
- 心筋のメカノ電気フィードバックは知られていますが,心室のストレッチによる不律症誘導のメカニズムは不明です.
- 慢性的な対急性心筋筋伸縮のリズム障害を引き起こす可能性については,依然として議論されています.
- 心筋伸縮の細胞電気生理学的効果については,さらなる評価が必要である.
研究 の 目的:
- 静脈の壁がゆっくりと伸びるか,速く伸びるかの電気生理学的およびリズム障害を引き起こす効果を調査する.
- 早期心房刺激 (PVEs) を誘発するストレッチ速度と振幅の役割を決定する.
主な方法:
- コンピュータ制御された左心室 (LV) 容量の変化を持つ,孤立したランゲンドルフ浸透ウサギの心臓モデルを使用した.
- マルチサイト単相アクションポテンシャル (MAP) 記録とボリューム駆動型EKGを使用して,細胞電気生理学とPVEを評価しました.
- 漸進的なボリュームランプと,幅度や上昇速度が異なる急速なボリュームパルスを適用した.
主要な成果:
- 漸進的な LV 負荷は MAP の振幅を低下させ,急速なパルスは一時的な脱極化を引き起こした.
- 急速なストレッチは定期的にPVE (45-100%) を引き起こすが,漸進的なストレッチはめったに起こらない (11%).
- PVEの確率は,ストレッチの振幅と速度,特に低い振幅で増加した;PVEは主に前側側頭葉で発生した.
結論:
- 急速な心房伸縮は,同様の膜脱極化にもかかわらず,漸進的な伸縮よりもPVEを容易に誘発します.
- 適合性の高い心筋膜領域は,ストレッチ誘発性不律症の焦点として機能する可能性があります.
- この発見は,ストレッチによって活性化されるチャネルを裏付け,異なる心室負荷の条件下での心室外皮を説明するものである.
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