These results indicate that SV increases when HR decrease,but the change of stroke volume is very small when HR is smaller than90/min,and the relative variation is not greater than3%.

• 结果表明,虽然每搏输出量随心率的增加而减小,但心率低于90次/分的情况下,每搏输出量随心率的变化很小,相对变化量不大于3%25。