Conclusion The hypothermia,extracorporeal circulation,clamp of aorta and drugs,etc.can lead to decrease of HRV in cardiac surgery.The resume of autonomic cardioneural system was a slow process.

结论心脏手、体外循环、低温、主动及药物因素可导心率变异性下降，心脏自主神经系统的恢复是一个缓慢的过程。