A function relationship exists between CO and HR.CO is in-creasing while HR is increasing.After the maximum point,the value of CO drops dramatically.

• 而心输出量与心率之间存在函数关系,心率较低的情况下,心输出量随心率的增大而增大,心输出量达到极大值后,心输出量随心率的增大而下降。