目的 分析不明原因心悸患者的心脏自主神经功能状态，探讨其发病机制。方法 选取不明原因心悸患者45例及健康对照组22例，进行24 h动态心电图检查并行心率变异性（HRV）分析，比较心悸组中动态心电图大致正常者与对照组24 h正常R-R间期标准差（SDNN）、每5 min正常R-R间期均值的标准差（SDANN）、相邻正常R-R间期差值的均方根（RMSSD）、SDNN＜100的例数、SDNN日夜比值以及LF/HF比值等指标。结果 不明原因心悸组与对照组平均心率无统计学差异。心悸组共检出室性心律失常8例（17.8%），均为单源性室性期前收缩，平均（83.2±119.3）个/ h；窦性心动过缓3例（6.7%）；阵发性室上性心动过速6例（13.3%）；动态心电图大致正常28例（62.2%）。对照组动态心电图均大致正常（100%）。心悸组除了窦性心动过缓者外，其余各组SDNN、SDANN多小于对照组（P＜0.05或P＜0.01），RMSSD各组间无显著差异。心悸组中动态心电图正常者的SDNN＜100为12例（42.9%），对照组为0例（0.0%），差异有统计学意义（χ²=12.4060，P＜0.05）。心悸组SDNN日夜比值及LF/HF比值增大，与对照组比较差异均有统计学意义（t=4.280、6.788，P＜0.01）。结论 不明原因心悸患者24 h动态心电图多数为大致正常，但心率变异性分析结果显示其心脏自主神经功能已有不同程度受损，主要表现为夜间迷走神经张力减低。

Objective To study the pathogenesis of palpitation of unknown causes in patients with cardiac autonomic nervous function. Methods Forty-five patients with palpitations of unknown causes and 22 healty controls were examined for 24 hours of dynamic electrocardiogram parallel heart rate variability (HRV) analysis, comparison of palpitation group dynamic electrocardiogram almost normal with control group of 24 h normal R-R interval standard deviation ( SDNN ), each 5 min normal R-R interval mean standard deviation ( SDANN ), adjacent normal R-R interval difference of root mean square ( RMSSD ), SDNN<100 cases, SDNN ratio and LF/HF ratio and other indicators．Results Unexplained palpitation group and control group showed no significant difference in mean heart rate. In palpitation group ventricular arrhythmia was detected in 8 patients (17.8%), which was single source of ventricular extrasystole, averaged (83.2 ±119.3) / h; sinus heartbeat bradycardia in 3 cases (6.7%); paroxysmal supraventricular tachycardia of heartbeat in 6 cases (13.3%); dynamic electrocardiogram was normal in 28 cases (62.2%). Dynamic electrocardiograms were normal in control group (100%). In palpitation group, in addition to sinus bradycardia heartbeat, the SDNN and SDANN were smaller than that in the control group (P<0.05 or P<0.01), but the RMSSD. In palpitation group, dynamic electrocardiogram normal with SDNN<100 in 12 cases (42.9% ), in the control group 0 case ( 0%), the difference was statistically significant (χ²=12.4060, P<0.05 ). Compared with the control group, the SDNN circadian ratio and LF/HF ratio in palpitation group increased (t=4.280, 6.788, P<0.01). Conclusions In patients with palpitations of unknown causes, 24 h dynamic electrocardiogram is in majority generally normal, but heart rate variability analysis Results show that the cardiac autonomic function is damaged to varying degrees, mainly manifested as decrease in nocturnal vagus tone.