Dependence of canine right coronary arterial flow upon heart rate and right ventricular pressure

为了阐明右冠状动脉(RCA)应对超负荷的确切机制，我们研究了9只开胸成年比格犬，分析了RCA的血流信号与独立变化的心率(起搏)和右室压(肺动脉环)的关系。心率和右室压的增加都增加了RCA的总流量，但舒张期/总流量比(D/T)随着心率的增加而增大，而随着心率的增加而下降。我们的数据也证实，RCA流量的增加主要是由收缩期的增加提供的，而右室压的增加则是由舒张期的增加提供的。RCA设法以两种不同的方式将血液输送到右心室肌肉系统，以应对心率和心室压的增加。慢性实验尚未得出最终结论。我们落后于赛程，部分原因是我周围的情况发生了一些不可避免的变化。我们计划在1996年按照原来的协议再做一些实验，以完成这项研究。

To elucidate the exact mechanisms for the right coronary artery (RCA) to cope with the overload, we studied nine open-chest adult Beagles and analyzed the flow signals of the RCA in relation to independently varied heart rate (pacing) and right ventricular pressure (pulmonary artery banding).Both increased heart rate and right ventricular pressure increased the total volume flow of the RCA.The diastolic over total flow ratio (D/T), however, enlarged on increasing right ventricular pressure while it declined on increasing heart rates. Our data confirmed, as well, that increased flow of RCA on rising heart rate was provided mainly by an increase in systolic phase, while the increase on augmented right ventricular pressure was provided by the increase in diastolic phase. The RCA manages to deliver blood to the right ventricular musculature in two different ways in response to increasing heart rate and ventricular pressure.Final conclusion from chronic experiments is not reached yet. We are left behind the schedule, partly because of some unavoidable alterations of situations around me. We are planning to do some more experiments according to the original protocol in 1996 to complete the study.