心室
心脏病学
内科学
血流
血流动力学
血管阻力
静脉血
医学
氧气
心输出量
单调的工作
麻醉
化学
有机化学
作者
Bradley J. Hart,Xiaoming Bian,Patricia A. Gwirtz,Srinath Setty,H. Fred Downey
出处
期刊:American Journal of Physiology-heart and Circulatory Physiology
[American Physiological Society]
日期:2001-08-01
卷期号:281 (2): H823-H830
被引量:43
标识
DOI:10.1152/ajpheart.2001.281.2.h823
摘要
This is the first investigation of right ventricular (RV) myocardial oxygen supply/demand balance in a conscious animal. A novel technique developed in our laboratory was used to collect right coronary (RC) venous blood samples from seven instrumented, conscious dogs at rest and during graded treadmill exercise. Contributions of the RV oxygen extraction reserve and the RC flow reserve to exercise-induced increases in RV oxygen demand were measured. Strenuous exercise caused a 269% increase in RV oxygen consumption. Expanded arteriovenous oxygen content difference (A-V(Delta)O2) provided 58% of this increase in oxygen demand, and increased RC blood flow (RCBF) provided 42%. At less strenuous exercise, expanded A-V(Delta)O2 provided 60-80% of the required oxygen, and increases in RCBF were small and driven by increased aortic pressure. RC resistance fell only at strenuous exercise after the extraction reserve had been mobilized. Thus RC resistance was unaffected by large decreases in RC venous PO2 until an apparent threshold at 20 mmHg was reached. Comparisons of RV findings with published left ventricular data from exercising dogs demonstrated that increased O2 demand of the left ventricle is met primarily by increasing coronary flow, whereas increased O2 extraction makes a greater contribution to RV O2 supply.
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