Jones D P, Damiano R, Cox J L, Wolfe W G
J Thorac Cardiovasc Surg. 1981 Aug;82(2):216-20.
Mechanical obstruction of the pulmonary artery causes an increase in right ventricular myocardial blood flow (MBF) proportional to the increased work load. This study was done to assess the response of MBF to hypoxia in the absence of mechanical obstruction of the right heart. The effects of hypoxia on cardiac performance and regional MBF were studied in ten awake, unanesthetized dogs at 4,600 m (15,000 feet). Intracardiac pressures and pulmonary artery (PA) and thoracic aorta blood gases were recorded daily, initially at sea level and subsequently at 3,000 m and 4,500 m altitude. Regional MBF was measured on days 1 (control), 3, and 5 by use of 8 to 10 mu radioactive tracer microspheres, followed by postmortem assessment of subepicardial and subendocardial flow patterns in the left ventricle (LV), septum, and right ventricle (RV) (4,600 m). The results indicate that: (1) RV and PA pressures increase linearly with increasing degrees of hypoxia, (2) MBF increases in both the RV and LV with increasing degrees of hypoxia and elevated right-sided pressures, without increased systemic pressure, and (3) the transmural distribution of MBF is unaltered in both the BV and LV with altitude-induced hypoxia. These findings are distinctly different from those in which right-sided pressures are elevated secondary to mechanical obstruction of the PA in the absence of hypoxia.
肺动脉的机械性梗阻会导致右心室心肌血流量（MBF）增加，且与工作量的增加成正比。本研究旨在评估在无右心机械性梗阻的情况下MBF对缺氧的反应。在海拔4600米（15000英尺）的高度，对10只清醒、未麻醉的犬进行了研究，观察缺氧对心脏功能和局部MBF的影响。每天记录心内压、肺动脉（PA）和胸主动脉血气，最初在海平面，随后在海拔3000米和4500米处。在第1天（对照）、第3天和第5天，使用8至10微居里放射性示踪微球测量局部MBF，随后对左心室（LV）、室间隔和右心室（RV）（海拔4600米）的心外膜下和心内膜下血流模式进行尸检评估。结果表明：（1）右心室和肺动脉压力随缺氧程度的增加呈线性增加；（2）随着缺氧程度的增加和右侧压力升高，右心室和左心室的MBF均增加，而全身压力未升高；（3）在海拔诱导的缺氧情况下，右心室和左心室MBF的透壁分布均未改变。这些发现与在无缺氧情况下因肺动脉机械性梗阻继发右侧压力升高的情况明显不同。
