Melenovsky Vojtech, Simek Jan, Sperl Michal, Malik Jan, Wichterle Dan
Third Department of Internal Medicine, First School of Medicine, Charles University, Prague, Czech Republic.
Am J Cardiol. 2005 Apr 15;95(8):999-1002. doi: 10.1016/j.amjcard.2004.12.048.
This study evaluated the effect of beta blockade on cardiac autonomic control and its dependence on heart rate change. The relations between RR interval duration, heart rate variability (HRV), and baroreflex sensitivity (BRS) were studied in 111 healthy men and in 21 male volunteers before and after a 100-mg oral dose of metoprolol. HRV and BRS correlated significantly with mean RR (r = 0.39, r = 0.57). Metoprolol administration increased both mean RR (from 996 to 1,176 ms, p <0.001), BRS from 24 to 36 ms/mm Hg (p = 0.003), and the SD of RR from 61 to 74 ms (p = 0.05). However, metoprolol-induced changes of HRV and BRS became insignificant (p = 0.69 and 0.48) after they were normalized to the same cycle length, suggesting that the improvement of cardiac autonomic control after beta blockade could be explained by a change of heart rate.
本研究评估了β受体阻滞剂对心脏自主神经控制的影响及其对心率变化的依赖性。在111名健康男性和21名男性志愿者口服100毫克美托洛尔前后，研究了RR间期持续时间、心率变异性（HRV）和压力反射敏感性（BRS）之间的关系。HRV和BRS与平均RR显著相关（r = 0.39，r = 0.57）。服用美托洛尔后，平均RR增加（从996毫秒增加到1176毫秒，p <0.001），BRS从24毫秒/毫米汞柱增加到36毫秒/毫米汞柱（p = 0.003），RR的标准差从61毫秒增加到74毫秒（p = 0.05）。然而，将美托洛尔引起的HRV和BRS变化归一化为相同的周期长度后，这些变化变得不显著（p = 0.69和0.48），这表明β受体阻滞剂后心脏自主神经控制的改善可以用心率变化来解释。
