Frøbert O, Mølgaard H, Bøtker H E, Bagger J P
Department of Cardiology, Skejby University Hospital, Aarhus N, Denmark.
Eur Heart J. 1995 Oct;16(10):1356-60. doi: 10.1093/oxfordjournals.eurheartj.a060742.
The pathophysiology of angina pectoris in patients with a normal coronary angiogram is not clear. Furthermore, the pathophysiological impact of ST changes in syndrome X is controversial. The purpose of this study was to investigate cardiac autonomic function, by measuring 24 h heart rate variability, in patients with and without electrocardiographic evidence of ischaemia during exercise. Thirty-two patients with angina pectoris, a normal coronary angiogram, echocardiogram, hyperventilation test and gastro-oesophageal investigation were studied. Fourteen healthy subjects served as controls. Fifteen patients had significant ST segment depression during stress testing, whereas 17 had no electrocardiographic signs of ischaemia. Heart rate variability was calculated as (1) mean RR = mean of all normal RR intervals, (2) the difference in mean RR level between when awake and when asleep (mean RR wake-sleep)-a tentative index of sympathetic activation, (3) the standard deviation (SD)-a broad band measure of autonomic balance, and (4) a percentage of successive RR interval differences > or = 6% (pNN6%)-an index of vagal modulation. The coronary vascular resistance was measured at rest and during pacing. Mean RR and autonomic indexes did not differ between patients with a positive exercise test and controls (831/884 ms; 24 h SD 125/134 ms; pNN6% 6.715.4%, respectively). Patients with a normal exercise test had shorter mean RR (758 ms vs 844 ms; P < 0.05) and significantly reduced 24-h SD (103 ms vs 134 ms; P < 0.05) than controls, whereas values for vagal index (6.5% vs 5.4%) did not differ from healthy controls. Mean RR wake-sleep also tended to be lower in patients with a normal exercise test (-125 ms vs -173 ms) compared to controls (P < 0.1). Patients with a positive exercise test had a significantly attenuated reduction in coronary vascular resistance during pacing in comparison to patients with a normal exercise test (-0.131 -0.26 mmHg x min. ml-1; P < 0.05). The findings suggest the occurrence of general elevated sympathetic activation in angina patients with a normal exercise test. Patients with a positive exercise test exhibited no signs of autonomic dysfunction although these patients had altered coronary vascular resistance indicating microvascular angina. This supports the suggestion that patients with a normal exercise test constitute an independent pathophysiological entity.
冠状动脉造影正常的心绞痛患者的病理生理学尚不清楚。此外，X综合征中ST段改变的病理生理影响存在争议。本研究的目的是通过测量24小时心率变异性，来调查运动期间有无心电图缺血证据的患者的心脏自主神经功能。研究了32例患有心绞痛、冠状动脉造影正常、超声心动图正常、过度通气试验正常且胃食管检查正常的患者。14名健康受试者作为对照。15例患者在应激试验期间有显著的ST段压低，而17例没有心电图缺血迹象。心率变异性计算如下：(1)平均RR = 所有正常RR间期的平均值；(2)清醒时与睡眠时平均RR水平之差(平均RR清醒-睡眠)——交感神经激活的一个初步指标；(3)标准差(SD)——自主神经平衡的一个宽带测量指标；(4)连续RR间期差异≥6%的百分比(pNN6%)——迷走神经调节的一个指标。在静息和起搏期间测量冠状动脉血管阻力。运动试验阳性的患者与对照组之间的平均RR和自主神经指标无差异(分别为831/884毫秒；24小时SD 125/134毫秒；pNN6% 6.7/15.4%)。运动试验正常的患者的平均RR较短(758毫秒对844毫秒；P<0.05)，24小时SD显著降低(103毫秒对134毫秒；P<0.05)，而迷走神经指数的值(6.5%对5.4%)与健康对照组无差异。与对照组相比，运动试验正常的患者的平均RR清醒-睡眠也倾向于较低(-125毫秒对-173毫秒)(P<0.1)。与运动试验正常的患者相比，运动试验阳性的患者在起搏期间冠状动脉血管阻力的降低明显减弱(-0.131/-0.26毫米汞柱·分钟·毫升-1；P<0.05)。这些发现表明，运动试验正常的心绞痛患者存在普遍升高的交感神经激活。运动试验阳性的患者没有自主神经功能障碍的迹象，尽管这些患者的冠状动脉血管阻力发生了改变，提示微血管性心绞痛。这支持了运动试验正常的患者构成一个独立病理生理实体的观点。
