Effects of Transcutaneous Acupoint Electrical Stimulation on Postoperative Heart Rate Variability and High-sensitive Cardiac Troponin of Elderly Patients With Coronary Heart Disease

General anesthesia can inhibit sympathetic nerve activity and attenuate stress response, but it also inhibits vagus nerve activity. The decrease of vagus nerve activity can cause cardiovascular complications, especially ventricular arrhythmia in patients with coronary heart disease. Some study have shown that electrical stimulation of transcutaneous acupoints can regulate the function of autonomic nervous system and enhance the activity of vagus nerve so as to protect myocardial tissue. But the effect on autonomic nervous function and myocardial injury markers in elderly patients with coronary heart disease was not reported. Heart rate variability (HRV) is a noninvasive and reliable index reflecting cardiac autonomic nervous function. High-sensitive cardiac troponin hs-cTnT is the best myocardial injury marker.

The investigators plan to recruite 150 patients with coronary heart disease of both sexes, aged 65-80 yr, undergoing elective lumbar decompression and fusion internal fixation surgery. They will be randomly divided into 2 groups(n=75 each)using random number table : control group ( group C ) and TAES group (group T). Patients in group T receive TEAS (disperse-dense waves, frequency 4/20Hz) at the points of PC6 (Neiguan) and PC4 (Ximen) from 30 min before anesthesia induction to the end of surgery, the optimal intensity will be adjusted to maintain a slight twitching of the midfinger or ring finger (De-Qi response). Patients in group C receive electrode plate at the same acupoints without any electrical stimulation. Heart rate variability will be collected on 1 day before surgery, 1, 3 and 5d after surgery. 3mL of venous blood will be collected before the induction of anesthesia, 1, 3 and 5d after surgery, the serum will be isolated for the measurement of serum concentration of high-sensitive troponin T (hs-cTnT)、CK、CRP.