New Index for Oxygen Cost of Contractility from Curved End-Systolic Pressure-Volume Relations in Cross-Circulated Rat Hearts

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We have already reported the linear oxygen consumption per beat (Vo<sub>2</sub>)–systolic pressure-volume area (PVA) relation from the curved left ventricular (LV) end-systolic pressure–volume relation (ESPVR) in the cross-circulated rat heart. The Vo<sub>2</sub> intercept (PVA-independent Vo<sub>2</sub>) is primarily composed of Vo<sub>2</sub> for Ca<sup>2+</sup> handling in excitation-contraction (E-C) coupling and basal metabolism. The aim of the present study was to obtain the oxygen cost of LV contractility that indicates Vo<sub>2</sub> for Ca<sup>2+</sup> handling in E-C coupling per unit LV contractility change in the rat heart. Oxygen cost of LV contractility is obtainable as a slope of a linear relation between PVA-independent Vo<sub>2</sub> and LV contractility. We obtained a composite Vo<sub>2</sub>–PVA relation line at a mid-range LV volume (mLVV) under gradually enhanced LV contractility by stepwise increased Ca<sup>2+</sup> infusion and thus the gradually increased PVA-independent Vo<sub>2</sub> values. As a LV contractility index, we could not use E<sub>max</sub> (ESP-V ratio; ESP/ESV) for the linear ESPVR because of the curved ESPVR in the rat LV. A PVA at a mLVV (PVA<sub>mLVV</sub>) has been proposed as a good index for assessing rat LV mechanoenergetics. Since the experimentally obtained PVA<sub>mLVV</sub> was not triangular due to the curved ESPVR, we propose an equivalent ESP-V ratio at a mLVV, (eESP/ESV)<sub>mLVV</sub>, as a LV contractility index. This index was calculated as an ESP-V ratio of the specific virtual triangular PVA<sub>mLVV</sub> that is energetically equivalent to the real PVA<sub>mLVV</sub>. The present approach enabled us to obtain a linear relation between PVA-independent Vo<sub>2</sub> and (eESP/ESV)<sub>mLVV</sub> and the oxygen cost of LV contractility as the slope of this relation.<br>

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  • The Japanese journal of physiology

    The Japanese journal of physiology 49(6), 513-520, 1999-12-01

    PHYSIOLOGICAL SOCIETY OF JAPAN

参考文献:  20件中 1-20件 を表示

被引用文献:  7件中 1-7件 を表示

各種コード

  • NII論文ID(NAID)
    10008308288
  • NII書誌ID(NCID)
    AA00691224
  • 本文言語コード
    ENG
  • 資料種別
    ART
  • ISSN
    0021521X
  • NDL 記事登録ID
    4979604
  • NDL 雑誌分類
    ZS8(科学技術--医学--解剖学・生理学・生化学)
  • NDL 請求記号
    Z53-D40
  • データ提供元
    CJP書誌  CJP引用  NDL  J-STAGE 
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