Ridha Mustafa, Mäkikallio Timo H, Lopera Gustavo, Pastor Juan, de Marchena Eduardo, Chakko Simon, Huikuri Heikki V, Castellanos Agustin, Myerburg Robert J
Cardiology (111-A), V.A. Medical Center, 1201 NW 16th Street, Miami, FL 33125, USA.
Ann Noninvasive Electrocardiol. 2002 Apr;7(2):133-8. doi: 10.1111/j.1542-474x.2002.tb00154.x.
Patients with congestive heart failure (CHF) have alterations in the traditional and nonlinear indices of heart rate (HR) dynamics, which have been associated with an increased risk of mortality. This study was designed to test the effects of carvedilol, a nonselective beta-blocker with alpha-1 blocking properties, on HR dynamics in patients with CHF.
We studied 15 patients with CHF secondary to ischemic or idiopathic cardiomyopathy who met the following inclusion criteria: NYHA functional class II-III, optimal conventional medical therapy, normal sinus rhythm, left ventricular ejection fraction (LVEF) of < 40%, and resting systolic blood pressure greater than 100 mmHg. The 6-minute corridor walk test, estimation of LVEF, and 24-hour Holter recording were performed at baseline and after 12 weeks of therapy with carvedilol. Traditional time and frequency domain measures and short-term fractal scaling exponent of HR dynamics were analyzed.
After 12 weeks of therapy with carvedilol, the mean LVEF improved significantly (from 0.27 +/- 0.08 to 0.38 +/- 0.08, P < 0.001). The average HR decreased significantly (from 86 +/- 11 to 70 +/- 8 beats/min, P < 0.001). The mean distance traveled in the 6-minute walk test increased significantly (from 177 +/- 44 to 273 +/- 55 m, P < 0.01). The frequency-domain indices (HF and LF), the time domain indices (rMSSD and PNN5 ), and the short-term fractal scaling exponent increased significantly. The scaling exponent increased particularly among the patients with the lowest initial values (< 1.0), and the change in the fractal scaling exponent correlated with the change in ejection fraction (r = 0.63, P < 0.01).
Carvedilol improves time and frequency domain indices of HR variability and corrects the altered scaling properties of HR dynamics in patients with CHF. It also improves LVEF and functional capacity. These specific changes in HR behavior caused by carvedilol treatment may reflect the normalization of impaired cardiovascular neural regulation of patients with CHF.
充血性心力衰竭（CHF）患者的心率（HR）动态传统指标和非线性指标均有改变，这些改变与死亡风险增加相关。本研究旨在测试具有α-1阻滞特性的非选择性β受体阻滞剂卡维地洛对CHF患者HR动态的影响。
我们研究了15例继发于缺血性或特发性心肌病的CHF患者，这些患者符合以下纳入标准：纽约心脏协会（NYHA）心功能II-III级、最佳常规药物治疗、正常窦性心律、左心室射血分数（LVEF）<40%以及静息收缩压大于100 mmHg。在基线时以及卡维地洛治疗12周后，进行6分钟走廊步行试验、LVEF评估和24小时动态心电图记录。分析了HR动态的传统时域和频域指标以及短期分形缩放指数。
卡维地洛治疗12周后，平均LVEF显著改善（从0.27±0.08提高到0.38±0.08，P<0.001）。平均HR显著降低（从86±11次/分钟降至70±8次/分钟，P<0.001）。6分钟步行试验中的平均行走距离显著增加（从177±44米增至273±55米，P<0.01）。频域指标（HF和LF）、时域指标（rMSSD和PNN5）以及短期分形缩放指数均显著增加。缩放指数在初始值最低（<1.0）的患者中增加尤为明显，分形缩放指数的变化与射血分数的变化相关（r = 0.63，P<0.01）。
卡维地洛可改善CHF患者HR变异性的时域和频域指标，并纠正HR动态改变的缩放特性。它还可改善LVEF和功能能力。卡维地洛治疗引起的HR行为的这些特定变化可能反映了CHF患者受损的心血管神经调节的正常化。
