Aronson D, Burger A J
Division of Cardiology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA.
Int J Cardiol. 2001 Jun;79(1):31-9. doi: 10.1016/s0167-5273(01)00401-6.
One of the putative mechanisms for the salutary effects of beta-blockers in patients with congestive heart failure is their ability to improve autonomic dysfunction. However, patients with profound neurohumoral abnormalities derive little survival benefit from beta-blockers. The purpose of the current study was to evaluate the effect of beta-blockers on heart rate variability in decompensated heart failure.
Time and frequency domain heart rate variability indices were obtained from 24-h Holter recordings and compared to assess the role of beta-blockade in 199 patients (mean age 60+/-14 years [range 21 to 87]) with decompensated heart failure (New York Heart Association functional class III [66%] and IV [34%]).
All heart rate variability indices were markedly suppressed but were substantially higher in patients who were on beta-blockers. Time domain measures of parasympathetic cardiac activity, the percentage of RR intervals with >50 ms variation (4.9+/-0.6 vs. 7.7+/-1.2%, P=0.006) and the square root of mean squared differences of successive RR intervals (22.7+/-2.0 vs. 31.6+/-4.1 ms, P=0.004), were higher in the beta-blocker group. Spectral analysis revealed that the total power and the ultra low frequency power were significantly higher in patients on beta-blockers (82% and 59%, respectively). The high frequency power, a spectral index of parasympathetic modulation, was 41% higher in the beta-blocker group (121+/-25 vs. 171+/-27 ms(2), P=0.02). Multiple linear regression, adjusted for clinical parameters and drug therapies, revealed a strong positive relationship between beta-blockade and higher values of time and frequency domain measures. The mean number of ventricular tachycardia episodes were significantly lower in patients on beta-blocker therapy (3.6+/-1.5 vs. 19.0+/-5.3, P=0.04).
beta-blockers improve the impaired cardiac autonomic regulation during high sympathetic stress of decompensated heart failure.
β受体阻滞剂对充血性心力衰竭患者有益的一种可能机制是其改善自主神经功能障碍的能力。然而，神经体液异常严重的患者从β受体阻滞剂中获得的生存益处甚微。本研究的目的是评估β受体阻滞剂对失代偿性心力衰竭患者心率变异性的影响。
从24小时动态心电图记录中获取时域和频域心率变异性指标，并进行比较，以评估β受体阻滞剂在199例（平均年龄60±14岁[范围21至87岁]）失代偿性心力衰竭（纽约心脏协会功能分级III级[66%]和IV级[34%]）患者中的作用。
所有心率变异性指标均明显受到抑制，但在服用β受体阻滞剂的患者中显著更高。副交感神经心脏活动的时域测量指标，RR间期变化>50毫秒的百分比（4.9±0.6对7.7±1.2%，P = 0.006）以及连续RR间期均方根差（22.7±2.0对31.6±4.1毫秒，P = 0.004），在β受体阻滞剂组中更高。频谱分析显示，服用β受体阻滞剂的患者总功率和超低频功率显著更高（分别为82%和59%）。高频功率作为副交感神经调节的频谱指标，在β受体阻滞剂组中高41%（121±25对171±27毫秒²，P = 0.02）。经临床参数和药物治疗校正后的多元线性回归显示，β受体阻滞剂与更高的时域和频域测量值之间存在强正相关。接受β受体阻滞剂治疗的患者室性心动过速发作的平均次数显著更低（3.6±1.5对19.0±5.3，P = 0.04）。
β受体阻滞剂可改善失代偿性心力衰竭高交感应激期间受损的心脏自主神经调节。
