非器质性心脏病的心脏变时功能不良和交感神经功能关系的探讨

目的 评价心脏变时功能不良的发生和自主神经功能调节的关系.方法 2006年至2009年75例（2006年至2008年南京医科大学第一附属医院心脏中心66例,2009年江苏大学附属武进医院心内科9例）平时窦性心动过缓的体检人群,男52,女23,年龄14 ～72（47.6±13.0）岁,进行运动平板试验和动态心电图检测,检测运动前及运动高峰时血浆去甲肾上腺素（NE）水平,运动前静息阶段至运动最高峰的心率（HR）、代谢当量（METS）和NE水平变化,△NE用对数标度表示（log△NE）,log△NE/运动时间和log△NE/METS表示运动中交感神经反应的敏感性.观察动态心电图的心率变异指标.按运动试验中运动后最大心率能否达85％年龄预测心率分为变时功能正常组（Non-CI组）及变时功能不良组（CI组）.结果 ①CI组动态心电图心率变异分析指标：低频（LF,49.44±40.73对27.88±12.55,P=0.04）、低频/高频比值（LF/HF,1.85±0.50对1.49±0.32,P=0.008）显著高于Non-CI组,RR间期的标准差（SDNN）、全程每5 min段RR间期平均值的标准差（SDANN）、相邻RR间期之差的均方根值（RMSSD）、相邻心搏RR间期的差值＞50 ms的心搏数占心搏总数的百分比（PNN50）、HF两组间差异无统计学意义;②CI组log△NE/METS（0.051 5±0.062 3对0.087 4±0.048 7,P=0.012）和log△NE/运动时间（0.049±0.062对0.080±0.046,P=0.019）明显低于Non-CI组.结论 心脏变时功能不良的发生和自主神经功能异常密切相关,对交感神经的反应迟钝可能是心脏变时功能不良发生的重要原因之一.

Relationship between sympathetic nerve function and chronotropic incompetence in people without organic heart disease

Objective To evaluate the relationship between chronotropic incompetence（CI） and autonomic nervous system.Methods From 2006 to 2009,75 persons with sinus bradycardia （52 men and 23 women,mean age 47.6± 13.0 years） received treadmill exercise test and a 24-hour Holter ECG.Plasma norepinephrine （NE） was measured at time of just before exercise and peak exercise.The changes in heart rate （HR）,metablic equivalent （METS） and NE from the resting state to peak exercise were calculated as △HR、△METS and △NE,respectively.Log△NE/METS,log△NE/exercise time was used as sympathetic activity to exercise.The heart rate variability （HRV） during Holter ECG were measured.Non-CI and CI were defined as whether or not to achieve 85% of the age predicted maximal heart rate （APMHR）.Results ①）HRV was significantly higher in subjects with CI than in those without CI：the low frequency （LF,49.44±40.73 vs.27.88± 12.55,P =0.04）and low frequency/high frequency （LF/HF,1.85 ±0.50 vs.1.49 ±0.32,P =0.008）.There was no significant difference in SDNN（standard deviation of normal to normal） 、SDANN（standard deviation of the averages of NN intervals in all 5-minute segments of the entire recording） 、RMSSD（root mean square values of the standard deviation between adjacent normal number of intervals） 、PNN50（NN50 count divided by the total number of all NN intervals）and HF（high frequency） between two groups.②）log△NE/△METS （0.051 5±0.062 3 vs.0.087 4±0.048 7,P=0.012）and log△NE/exercise time （0.049±0.062 vs.0.080±0.046,P=0.019）were significantly lower in patients with CI than in those without CI.Conclusion CI is closely related autonomic nervous system.Impaired sympathetic response may be an important reason for CI.