Paridon S M, Bricker J T, Dreyer W J, Reardon M, Smith E O, Porter C B, Michael L, Fisher D J
Department of Pediatrics, Baylor College of Medicine, Houston, Texas.
Pediatr Res. 1989 Mar;25(3):280-4. doi: 10.1203/00006450-198903000-00015.
We evaluated the adequacy of regional and transmural blood flow during exercise and rapid pacing after 1 wk of hypoxemia. Seven mature mongrel dogs were made hypoxemic (mean O2 saturation = 72.4%) by anastomosis of left pulmonary artery to left atrial appendage. Catheters were placed in the left atrium, right atrium, pulmonary artery, and aorta. Atrial and ventricular pacing wires were placed. An aortic flow probe was placed to measure cardiac output. Ten nonshunted dogs, similarly instrumented, served as controls. Recovery time was approximately 1 wk. Cardiac output, mean aortic pressure, and oxygen saturation were measured at rest, with ventricular pacing, atrial pacing, and with treadmill exercise. Ventricular and atrial pace and exercise were at a heart rate of 200. Right ventricular free wall, left ventricular free wall, and septal blood flow were measured with radionuclide-labeled microspheres. Cardiac output, left atrial blood pressure, and aortic blood pressure were similar between the two groups of dogs in all testing states. Myocardial blood flow was significantly higher in the right and left ventricular free wall in the hypoxemic animals during resting and exercise testing states. Myocardial oxygen delivery was similar between the two groups of animals. Pacing resulted in an increase in myocardial blood flow in the control animals but not the hypoxemic animals.(ABSTRACT TRUNCATED AT 250 WORDS)
我们评估了低氧血症1周后运动和快速起搏期间局部及透壁血流的充足性。通过将左肺动脉与左心耳吻合，使7只成年杂种犬处于低氧血症状态（平均氧饱和度 = 72.4%）。将导管分别置于左心房、右心房、肺动脉和主动脉中。放置心房和心室起搏电极。放置主动脉血流探头以测量心输出量。10只未分流的犬同样进行仪器植入，作为对照。恢复时间约为1周。在静息状态、心室起搏、心房起搏及跑步机运动时测量心输出量、平均主动脉压和氧饱和度。心室和心房起搏以及运动时心率均为200。用放射性核素标记的微球测量右心室游离壁、左心室游离壁和室间隔的血流。在所有测试状态下，两组犬的心输出量、左心房血压和主动脉血压相似。在静息和运动测试状态下，低氧血症动物右心室和左心室游离壁的心肌血流显著更高。两组动物的心肌氧输送相似。起搏使对照动物的心肌血流增加，但低氧血症动物未增加。（摘要截断于250字）
