男，56岁，充血性心力衰竭，心率长期维持在100～110次／分，口服地高辛0.25mg1次／日，治疗2周后心率无明显下降为了控制心率应首先的措施是（）
A.增加地高辛用量
B.加用普罗帕酮
C.加用胺碘酮
D.加用维拉帕米
E.β受体阻断药
参考答案：E
解析：充血性心力衰竭又称慢性心功能不全，地高辛是洋地黄类药物，属于正性肌力药物洋地黄治疗心衰时剂量与心肌收缩效应呈线性关系，盲目增加洋地黄剂量不仅易引起中毒反应，且可能加重心衰。另外胺碘酮和维拉帕米均可降低地高辛的经肾排泄率而增加中毒的可能性，所以均排除。普罗帕酮有轻度的降压和减慢心率的作用，但心衰禁忌。β受体阻滞剂对舒张性心功能不全有效，它可减慢心率，延长心室舒张期充盈时间增加冠脉血流灌注，且可改善心肌弛缓性和顺应性）
In many parts of the world, cars play an important role in daily life and many societies would not exist without them. 1 But this is the prediction made by a team of transport researchers who are taken seriously, not only by government but also by car manufacturers. The Human Science and Advanced Technology Institute at Loughborough in the UK is part of an international research program. 2 That will mean much saving, no accidents and better use of roads. The super-intelligent car in the future will drive itself. 3 Instead, we will have a choice of cars and change them as frequently as we change our clothing. According to Dr. David Davis, who leads the research team, these predictions are based on the rising cost of the car culture, which had blocked up our cities, polluted our air, and caused more deaths than both world wars put together. Davis says, cars will be fitted with some intelligent devices(装置) to regulate(调节) the distance between one car and another. 4 computers are much safer drivers than people, so cars in a road train will be able to drive much closer together than cars driven by people. By 2010, Dr. David Davis believes, car technology will give motorists a clear view of the road, whatever the weather conditions, by projecting an image of the road ahead on to the car’s windscreen. 5 Cars will be connected by an electronic tow bar to the car in front to form “road-trains”. “The front vehicle in such a train burns the normal amount.”says Davis. “but all the others in the train would burn about ten percent of the normal amount, and so produce about ten percent of the pollution.”
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