Influence of nonuniformity on rate of left ventricular pressure fall in the dog.
Influence of nonuniformity on rate of left ventricular pressure fall in the dog.
复制标题
不均匀性对狗左心室压力下降速率的影响。
DOI：
10.1152/ajpheart.1989.256.1.h222
复制
发表时间：
1989
期刊：
影响因子：
--
通讯作者：
Rasmussen,CM
中科院分区：
文献类型：
--
作者：
Lew,WY;Rasmussen,CM
我们在10只麻醉狗上研究了局部心室功能不均匀性对左心室压力下降速率的影响。在左心室前壁、侧壁和后壁植入超声节段测量器。在7只犬中，通过以低流量（0.5 +/- 0.7 ml/min）和高流量（1.5 +/- 1.2 ml/min）速率将异丙肾上腺素（0.4 μ g/ml）输注至冠状动脉左前降支中段，产生不均匀性，总剂量分别为0.1 +/- 0.1和0.3 +/- 0.2 μ g。这产生了剂量依赖性增加眼前节缩短缩短，缩短完成较早，显着的节段延长发生在等容舒张。不直接刺激外侧节和后节。心率、左心室舒张末期压和收缩压峰值保持恒定。然而，左心室压力下降的时间常数tau在低剂量时从32 +/- 8增加到37 +/- 10 ms，在高剂量时从35 +/- 6增加到49 +/- 12 ms。当将异丙肾上腺素输注到左前降支近端、中段或远端时，2只犬和在左回旋支冠状动脉输注时，3只犬出现了类似的结果。结论：左室局部功能的不均匀性是影响射血左室压力下降的重要因素。
We examined the influence of nonuniformity in regional ventricular function on the rate of left ventricular pressure fall in 10 anesthetized dogs. Ultrasonic segment gauges were implanted in the midwall of the anterior, lateral, and posterior left ventricle. In seven dogs, nonuniformity was produced by infusing isoproterenol (0.4 microgram/ml) into the mid-left anterior descending coronary artery at low flow (0.5 +/- 0.7 ml/min) and high flow (1.5 +/- 1.2 ml/min) rates, for total doses of 0.1 +/- 0.1 and 0.3 +/- 0.2 micrograms, respectively. This produced a dose-dependent increase in anterior segment shortening so that shortening was completed earlier and marked segment lengthening occurred during isovolumic relaxation. Lateral and posterior segments were not directly stimulated. The heart rate, left ventricular end-diastolic pressure, and peak systolic pressure remained constant. However, tau, the time constant of left ventricular pressure fall, increased from 32 +/- 8 to 37 +/- 10 ms with the low dose, and from 35 +/- 6 to 49 +/- 12 ms with the high dose of isoproterenol. Similar results occurred in two dogs when isoproterenol was infused into the proximal, mid, or distal left anterior descending and in three dogs with infusions in the left circumflex coronary artery. We conclude that nonuniformity of regional left ventricular function is an important and independent factor regulating the rate of pressure fall in the intact ejecting left ventricle.