Raine A E, Pickering T G
Br Med J. 1977 Jul 9;2(6079):90-2. doi: 10.1136/bmj.2.6079.90.
The response to dynamic exercise was investigated in 21 patients receiving long-term treatment with beta-adrenoceptor antagonists and 22 controls. An electrocardiogram (ECG) and blood pressure were recorded before and after treadmill exercise, and plasma dopamine-beta-hydroxylase (DBH) activity was measured as an index of changes in sympathetic activity. Heart rate and blood pressure were lower at rest and throughout exercise in treated patients, although the pressor effect of exercise was not reduced. The ECG P-R interval was lengthened, and in addition the Q-T interval was prolonged. After exercise, plasma DBH activity was significantly increased in controls but not in treated patients. We conclude that long-term administration of beta-adrenergic blockers increases myocardial repolarisation time and reduces sympathetic nervous activity. These actions may contribute to the antiarrhythmic and hypotensive effects of long-term beta-blockade.
对21例接受β-肾上腺素能受体拮抗剂长期治疗的患者和22例对照者进行了动态运动反应的研究。在跑步机运动前后记录心电图（ECG）和血压，并测量血浆多巴胺-β-羟化酶（DBH）活性作为交感神经活动变化的指标。治疗组患者在静息时和整个运动过程中的心率和血压较低，尽管运动的升压作用并未降低。心电图P-R间期延长，此外Q-T间期也延长。运动后，对照组血浆DBH活性显著增加，而治疗组患者未增加。我们得出结论，长期给予β-肾上腺素能阻滞剂可延长心肌复极时间并降低交感神经活动。这些作用可能有助于长期β受体阻滞剂的抗心律失常和降压作用。
