Robotham J L, Mintzner W
J Appl Physiol Respir Environ Exerc Physiol. 1979 Mar;46(3):411-8. doi: 10.1152/jappl.1979.46.3.411.
We have investigated the interaction of left ventricular afterload and right-heart volume on left ventricular performance. By utilizing a right-heart bypassed heart-lung preparation, we have been able to control independently each factor. We have previously suggested that the major influences of the inspiratory decrease in pleural pressure in decreasing left ventricular stroke volume (LVSV) may be via the inspiratory increases in left-heart afterload and right-heart volume (RHV). Thus, our preparation serves as a model to study in detail the specific effects on the left ventricle of changes that are induced by respiration. Our results show that increases in transmural (relative to pleural pressure) aortic pressure (Pao) caused an increased left ventricular end-diastolic pressure (LVEDP), and that the effect of equivalent increases in Pao was greater when RHV was greater. Increase in RHV had minimal effects at low volume, but resulted in large increases in LVEDP at large RHV. These effects were markedly attenuated after pericardiectomy. Rapid increases in either RHV or Pao produced transient falls in LVSV. Our results are consistent with the hypothesis that increases in both right-heart volume and LV afterload contribute to the inspiratory decrease in LVSV and increase in LVEDP.
我们研究了左心室后负荷与右心容量对左心室功能的相互作用。通过使用右心旁路心肺制备模型，我们能够独立控制每个因素。我们之前曾提出，吸气时胸膜压力降低导致左心室每搏输出量（LVSV）减少的主要影响可能是通过吸气时左心后负荷和右心容量（RHV）的增加。因此，我们的制备模型可作为一个详细研究呼吸引起的变化对左心室特定影响的模型。我们的结果表明，跨壁（相对于胸膜压力）主动脉压（Pao）升高会导致左心室舒张末期压力（LVEDP）升高，并且当RHV较大时，Pao同等程度升高的影响更大。RHV增加在低容量时影响最小，但在高RHV时会导致LVEDP大幅增加。心包切除术后这些影响明显减弱。RHV或Pao的快速增加会导致LVSV短暂下降。我们的结果与以下假设一致，即右心容量增加和左心室后负荷增加均导致吸气时LVSV减少和LVEDP增加。
