Witte K K A, Thackray S D R, Nikitin N P, Cleland J G F, Clark A L
Academic Cardiology, Castle Hill Hospital, Castle Road, Cottingham, Hull, UK.
Heart. 2003 Oct;89(10):1169-73. doi: 10.1136/heart.89.10.1169.
To assess the influence of acute alpha and beta blockade on ventilation and symptoms of breathlessness during exercise in patients with chronic heart failure and in controls.
11 patients with chronic heart failure and 11 control subjects underwent repeated exercise testing with metabolic gas exchange after random, double blind administration of either an alpha blocker and placebo, a beta blocker and a placebo, both an alpha blocker and a beta blocker, or double placebo.
Patients had a lower peak oxygen consumption (mean (SD) 20.7 (4.9) v 37.6 (9.6) ml/kg/min, p < 0.0001) and a steeper slope relating ventilation to carbon dioxide production (VE/CO2 slope) (26.5 (4.1) v 37.1 (8.2), p = 0.0011), than controls. Blood pressure was lower following alpha and beta blockade (p < 0.05) and the gradients of the slopes relating heart rate to oxygen consumption following the beta blocker were reduced (p < 0.05). Exercise time and peak ventilatory variables following beta or alpha blockers were unchanged. Ventilation was reduced during submaximal exercise following the active medications. Combined alpha and beta blockade produced the greatest difference (p < 0.005), but the alpha and beta blockers alone also reduced ventilation (p < 0.05). There was no difference in perceived exertion during exercise with any of the treatments.
Acute sympathetic inhibition can reduce submaximal ventilation during exercise in patients with heart failure and control subjects, suggesting that autonomic nervous system activation has an important role in the abnormal ventilatory response to exercise in chronic heart failure.
评估急性α和β受体阻滞剂对慢性心力衰竭患者及对照组运动期间通气和呼吸困难症状的影响。
11例慢性心力衰竭患者和11例对照受试者在随机、双盲给予α受体阻滞剂和安慰剂、β受体阻滞剂和安慰剂、α受体阻滞剂与β受体阻滞剂联合用药或双安慰剂后，进行重复运动测试并测定代谢气体交换情况。
与对照组相比，患者的峰值耗氧量较低（均值（标准差）20.7（4.9）对37.6（9.6）ml/kg/min，p<0.0001），且通气与二氧化碳产生的斜率（VE/CO2斜率）更陡（26.5（4.1）对37.1（8.2），p = 0.0011）。α和β受体阻滞剂治疗后血压降低（p<0.05），β受体阻滞剂治疗后心率与耗氧量关系的斜率梯度减小（p<0.05）。β或α受体阻滞剂治疗后的运动时间和峰值通气变量未改变。活性药物治疗后，次最大运动量运动期间通气减少。α和β受体阻滞剂联合用药产生的差异最大（p<0.005），但单独使用α和β受体阻滞剂也会降低通气（p<0.05）。任何一种治疗方式下运动期间的主观用力程度均无差异。
急性交感神经抑制可降低心力衰竭患者和对照受试者运动期间的次最大通气量，提示自主神经系统激活在慢性心力衰竭患者对运动的异常通气反应中起重要作用。
