Bauernschmitt R, Malberg H, Wessel N, Kopp B, Schirmbeck E U, Lange R
Clinic for Cardiovascular Surgery, German Heart Center Munich, Lazarettstr. 36, D-80636 Munich, Germany.
Eur J Cardiothorac Surg. 2004 Mar;25(3):320-6. doi: 10.1016/j.ejcts.2003.12.019.
Impairment of the baroreceptor reflex activity reflects an alteration of the autonomous regulation of the cardiovascular system and has proven to predict fatal outcome in patients after acute myocardial infarction. The following study was performed to analyse the baroreceptor sensitivity, heart rate variability and blood pressure variability in patients early after coronary surgery.
Twenty-five male patients undergoing coronary artery bypass were examined in a prospective study; normal values were obtained from healthy volunteers. Arterial pressure signals were recorded from a radial artery catheter for 30 min preoperatively and in short intervals after surgery. Mechanical manipulations and pharmacological interventions were avoided during the sampling periods. Baroreflex function was calculated according to the dual sequence method, heart rate variability and blood pressure variability were calculated including nonlinear methods.
Initial values of the patients did not differ from healthy volunteers. The strength of baroreflex sensitivity (increase in blood pressure causing a synchronous decrease of heart rate) is low 2 h postoperatively. The number of delayed tachycardic changes of heart rate, which are caused by sympathetic activation, is only moderately reduced as compared to values obtained from healthy volunteers. Heart rate variability is widely unchanged as compared to preoperative values; blood pressure variability showed an increase of low-frequency components, again indicating sympathetic predominance. Nonlinear analyses revealed reduced system complexity at the beginning of the postoperative course.
Obviously, there is a vagal suppression 20 h after surgery, while the sympathetic tonus works in a normal range. This unbalanced interaction of the autonomous systems is similar to findings in patients after myocardial infarction. The predictive value of these markers has to be elucidated in further clinical studies.
压力感受器反射活动受损反映了心血管系统自主调节功能的改变，并且已被证明可预测急性心肌梗死后患者的致命结局。进行以下研究以分析冠状动脉手术后早期患者的压力感受器敏感性、心率变异性和血压变异性。
在一项前瞻性研究中检查了25名接受冠状动脉搭桥术的男性患者；从健康志愿者获得正常值。术前从桡动脉导管记录30分钟的动脉压力信号，并在术后短时间间隔内记录。在采样期间避免进行机械操作和药物干预。根据双序列法计算压力反射功能，包括非线性方法计算心率变异性和血压变异性。
患者的初始值与健康志愿者无差异。术后2小时压力反射敏感性强度（血压升高导致心率同步下降）较低。与从健康志愿者获得的值相比，由交感神经激活引起的心率延迟心动过速变化的数量仅适度减少。与术前值相比，心率变异性基本未变；血压变异性显示低频成分增加，再次表明交感神经占优势。非线性分析显示术后病程开始时系统复杂性降低。
显然，术后20小时存在迷走神经抑制，而交感神经张力在正常范围内起作用。自主系统的这种不平衡相互作用与心肌梗死后患者的发现相似。这些标志物的预测价值必须在进一步的临床研究中阐明。
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