End-systolic pressure-diameter relationships during pulsus alternans in intact pig hearts.
End-systolic pressure-diameter relationships during pulsus alternans in intact pig hearts.
复制标题
完整猪心脏交替脉期间收缩末压力-直径关系。
DOI：
10.1152/ajpheart.1986.250.4.h606
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发表时间：
1986
期刊：
影响因子：
--
通讯作者：
Nellis,SH
中科院分区：
文献类型：
--
作者：
Miller,WP;Liedtke,AJ;Nellis,SH
交替搏动以前被归因于舒张末期纤维长度和/或交替收缩状态的变化。在六个起搏，全血灌注，完整的，工作的猪心，左心室内径测量超声晶体，左心室压力测量与微压计尖端导管。用普萘洛尔（24-51微克X kg-1 X min-1）诱导交替脉。使用先前描述的技术，从一系列连续的、无容量负荷的搏动中确定交替脉期间收缩末期压力-直径关系。在负荷条件发生任何变化之前分析的搏动显示，强搏动的左心室压力为62.7 +/- 8.7 mmHg，弱搏动的左心室压力为55.2 +/- 7.0 mmHg（P <0.050）。较强心搏前舒张末期内径大于较弱心搏前舒张末期内径（24.80 ± 2.73 mm vs. 23.82 ± 2.82 mm，P <0.025），但相应舒张末期压无显著差异。强心搏的最大dP/dt为1，275 +/- 249 mmHg/s，弱心搏为1，038 +/- 222 mmHg/s（P <0.025）。收缩末期压力-直径关系的斜率提供了一个独立于舒张末期直径的收缩指数，强搏动的平均值为42.3 +/- 6.4 mmHg/mm，弱搏动的平均值为24.4 +/- 6.8 mmHg/mm（P <0.025）。这些数据支持交替收缩状态作为完整动物交替脉的独立机制。
Pulsus alternans has previously been ascribed to variations in end-diastolic fiber length and/or an alternating contractile state. In six paced, whole blood-perfused, intact, working pig hearts, left ventricular internal diameters were measured with ultrasonic crystals, and left ventricular pressures were measured with a micromanometer-tipped catheter. Pulsus alternans was induced with propranolol (24-51 micrograms X kg-1 X min-1). End-systolic pressure-diameter relationships were determined during pulsus alternans from a series of consecutive, variably volume-loaded beats using a previously described technique. Beats analyzed prior to any change in loading conditions revealed a left ventricular pressure of 62.7 +/- 8.7 mmHg for the strong beats and 55.2 +/- 7.0 for the weak beats (P less than 0.050). The end-diastolic diameter prior to the stronger beats was larger than that prior to the weaker beats (24.80 +/- 2.73 vs. 23.82 +/- 2.82 mm, P less than 0.025), but there was no significant difference in the corresponding end-diastolic pressures. The maximum dP/dt of the strong beats was 1,275 +/- 249 mmHg/s compared with 1,038 +/- 222 for the weak beats (P less than 0.025). The slope of the end-systolic pressure-diameter relationship, which provides an index of contractility independent of end-diastolic diameter, averaged 42.3 +/- 6.4 mmHg/mm for the strong beats and 24.4 +/- 6.8 for the weak beats (P less than 0.025). These data support an alternating contractile state as an independent mechanism for pulsus alternans in the intact animal.