实验性心肌缺血大鼠心脏自主神经活性的动态变化及意义

采用心率变异（ＨＲＶ）时域及频域指标分析急性心肌缺血２４ｈ大鼠心脏自主神经功能的变化以探讨其意义。将实验动物分成三组，即正常对照组（２０只）、假手术组（２０只）与心肌缺血组（４８只），并运用动态心电图记录２４ｈ心电信号变化。结果显示：与假手术组及正常对照组分别比较，心肌缺血组正常窦性心律ＲＲ间期标准差（ＳＤＮＮ）下降（２８．９±９．４ｍｓｖｓ３４．４±１３．７ｍｓ或３５．１±１４．３ｍｓ，Ｐ均＜０．０５），低频（ＬＦ）及低频与高频的比值（ＬＦ／ＨＦ）明显增加（１８９．４±３６．５ｍｓ２／Ｈｚｖｓ５７．３±１７．８ｍｓ２／Ｈｚ或５１．８±１８．６ｍｓ２／Ｈｚ；３．８５±０．９１ｖｓ１．７６±０．６３或１．６８±０．５７，Ｐ均＜０．０１）；２４ｈ心率功率谱示心肌缺血组ＬＦ及ＬＦ／ＨＦ波动幅度较假手术组及正常对照组增高，缺血大鼠ＬＦ与ＬＦ／ＨＦ在缺血后０～３ｈ（２６７．５±１２．４ｍｓ２／Ｈｚ、４．３３±１．０８）及９～１２ｈ（２４４．７±１３．９ｍｓ２／Ｈｚ、３．９６±０．９８）期间增高显著，而在缺血后５～７ｈ（１４９．２±８．７ｍｓ２／Ｈｚ、２．０５±０．４２）内则相对较低。结果表明大鼠心肌缺血后ＨＲＶ降低主?

Dynamic Change and Implication of Cardiac Autonomic Nerve Activity in Rats With Experimental Myocardial Ischemia During 24 Hours

The study was designed to test the changes and implication of cardiac autonomic nerve activity in rats with 24 hours(h) of acute myocardial ischemia by time and frequency domain measures of heart rate variability (HRV).The electrocardiogram(ECG) of 24h was recorded from rats with normal control group (20 rats),sham operated group (20 rats) and myocardial ischemia group (48 rats) by Holter recorder.The results showed standard deviation of all normal RR intervals(SDNN) in entire 24h ECG recording was lower,but value of low frequency (LF) and the ratio of low to high frequency power (LF/HF) were significantly higher in myocardial ischemia group than that in sham operated group or normal control group (SDNN:28.9±9.4 ms vs 34.4±13.7 ms or 35.1±14.3 ms,P<0.05;LF:189.4±36.5 ms2/Hz vs 57.3±17.8 ms2/Hz or 51.8±18.6 ms2/Hz,P<0.01;LF/HF:3.85±091 vs 1.76±063 or 1.68±0.57,P<0.01).Dynamic analysis of heart rate power spectrum(HRPS) indicated that the differences in LF value and LF/HF value were larger in myocardial ischemia group when compared with sham operated group or normal control group.In rats with myocardial ischemia,the value of LF and LF/HF increased significantly during the periods of 0～3 h(LF:267.5±12.4 ms2/Hz,LF/HF:4.33±1.08) and 9～12 h (LF:244.7±13.9 ms2/Hz;LF/HF:396±098),but decreased relatively during the period of 5～7 h(LF:149.2±8.7 ms2/Hz;LF/HF:2.05±042) after myocardial ischemia.It was concluded that the decrease of HRV in rats with myocardial ischemia was mainly associated with the significant increases in sympathetic nerve activity and the relatively depress of vagal nerve activity.It is suggested that LF/HF is very important in evaluating cardiac autonomic nerve activity by HRV.