Vaillant Fanny, Abell Emma, Bear Laura R, Caluori Guido, Belterman Charly, Coronel Ruben, Ploux Sylvain, Santos Pierre Dos
University of Bordeaux, INSERM, CRCTB, U1045, Pessac, France.
IHU Liryc, Université de Bordeaux, Pessac, France.
J Physiol. 2025 Jan;603(2):285-300. doi: 10.1113/JP286259. Epub 2024 Dec 26.
The pericardium plays an important role in mechanical interactions between the right (RV) and left (LV) ventricles, referred to as ventricular interdependence. However, the exact mechanisms of its supportive role remain unknown. The present study aimed to evaluate specifically ventricular interdependence in a model of isolated biventricular working heart of large mammal, which is in absence of neurohormonal influence or series interactions, and to evaluate the impacts of intact pericardium on this phenomenon. Pig hearts were excised with the pericardium intact and connected to a biventricular working mode setup. Low and high ventricular preloads and afterloads were imposed on the hearts by changing independently the left (LA) and right (RA) atrial pressures, or the aortic (Ao) and pulmonary artery (PA) pressures, respectively, in the presence or absence of an intact pericardium. In the presence of the pericardium, increasing atrial pressures mainly impacted the ipsilateral ventricular haemodynamics, including an increase in ventricular outflow and end-diastolic pressures, independent of the contralateral atrial pressure. LV haemodynamics were also mainly altered by the increase in the ipsilateral afterload (Ao pressure). By contrast, RV haemodynamics, including the PA flow, were not only affected by increasing its ipsilateral (PA pressure), but also by its contralateral (Ao pressure) ventricular afterload. The preload but not afterload-dependent effects were abolished after removing the pericardium. Our work indicates that RV haemodynamics are highly impacted by the pericardiectomy. This highlights the requirement of keeping the pericardium intact to explore accurately cardiac haemodynamics, particularly in the RV. KEY POINTS: Pericardium has an important role in maintaining mechanical interventricular interaction, even if it is not essential for life. We used an ex vivo biventricular working pig heart model to explore intrinsic ventricular responses to independent variations of left and right preload and afterload, in the presence and absence of the pericardium. We show that, in the presence of the pericardium, the right ventricular haemodynamics is impacted by the ipsilateral preload as well as the ipsi- and contralateral afterloads, whereas the left ventricular haemodynamics is only impacted by its ipsilateral pre- and afterload. The preload but not afterload-dependent effects are abolished after removing the pericardium. These results demonstrate a critical function of the pericardium in maintaining RV haemodynamics, as well as preload-dependent ventricular interactions.
心包在右心室（RV）和左心室（LV）之间的机械相互作用中发挥着重要作用，这种作用被称为心室相互依存。然而，其支持作用的确切机制仍不清楚。本研究旨在专门评估大型哺乳动物离体双心室工作心脏模型中的心室相互依存情况，该模型不存在神经激素影响或串联相互作用，并评估完整心包对这一现象的影响。将猪心脏完整切除心包后，连接到双心室工作模式装置上。在有或无心包完整的情况下，分别通过独立改变左心房（LA）和右心房（RA）压力，或主动脉（Ao）和肺动脉（PA）压力，对心脏施加低和高心室前负荷及后负荷。在心包存在的情况下，增加心房压力主要影响同侧心室血流动力学，包括心室流出量和舒张末期压力增加，且与对侧心房压力无关。左心室血流动力学也主要因同侧后负荷（Ao压力）增加而改变。相比之下，右心室血流动力学，包括肺动脉血流量，不仅受同侧（PA压力）增加的影响，还受对侧（Ao压力）心室后负荷的影响。去除心包后，前负荷依赖性效应消失，但后负荷依赖性效应未消失。我们的研究表明，心包切除术对右心室血流动力学有很大影响。这突出了保持心包完整以准确探究心脏血流动力学的必要性，尤其是在右心室方面。要点：心包在维持心室间机械相互作用中起重要作用，即使它并非生命所必需。我们使用离体双心室工作猪心脏模型，探究在有或无心包的情况下，心室对左右前负荷和后负荷独立变化的内在反应。我们发现，在心包存在时，右心室血流动力学受同侧前负荷以及同侧和对侧后负荷的影响，而左心室血流动力学仅受其同侧前负荷和后负荷的影响。去除心包后，前负荷依赖性效应消失，但后负荷依赖性效应未消失。这些结果证明了心包在维持右心室血流动力学以及前负荷依赖性心室相互作用方面的关键作用。
