Department of Veterans Affairs Medical Center and the University of Colorado, Denver, Colorado, USA.
Rev Esp Cardiol. 2010 Jan;63(1):81-95. doi: 10.1016/s1885-5857(10)70012-8.
The primary purpose of the right ventricle and pulmonary circulation is gas exchange. Because gas exchange occurs in thin, highly permeable alveolar membranes, pulmonary pressure must remain low to avoid pulmonary edema; because the right ventricle and the lungs are in series with the left ventricle and the systemic circulation, the entire cardiac output must pass through the lungs. This low pressure, high volume system, makes dramatically different demands on the right ventricle compared with the demands made on the left ventricle by the systemic circulation. Moreover, the right ventricle and pulmonary circulation must buffer dynamic changes in blood volume and flow resulting from respiration, positional changes, and changes in left ventricular cardiac output. The optimizations needed to meet these conflicting demands result in reduced capacity to compensate for increased afterload or pressure. Unfortunately, a large number of pathologic processes can result in acute and or chronic increases in afterload stress. As afterload stress rises, right heart failure may develop, and hemodynamic instability and death can occur abruptly. Several biochemical pathways have been identified that may participate in adaptation or maladaptation to excessive pressure loads.
右心室和肺循环的主要功能是进行气体交换。由于气体交换发生在薄且具有高度通透性的肺泡膜上，为了避免肺水肿，肺内压力必须保持较低水平；由于右心室和肺与左心室和体循环串联，所以全部心输出量必须流经肺部。这种低压、高容量系统对右心室的需求与体循环对左心室的需求大不相同。此外，右心室和肺循环必须缓冲因呼吸、体位变化和左心室心输出量变化而导致的血量和血流的动态变化。为了满足这些相互冲突的需求而进行的优化导致了其对后负荷或压力增加的代偿能力降低。不幸的是，大量病理过程可导致后负荷应激的急性和/或慢性增加。随着后负荷应激的增加，可能会发生右心衰竭，并且可能会突然出现血流动力学不稳定和死亡。已经确定了几种可能参与对过度压力负荷的适应或不适应的生化途径。
