鉴别室速与阵发性室上速最有力的证据是（）
A.QRS波群宽大畸形的程度
B.是否存在房室分离
C.心室率的快慢
D.静脉应用普罗帕酮是否可终止
E.对迷走神经刺激的反应
参考答案：B
解析：下列心电图表现提示为室性心动过速：①室性融合波；②心室夺获；③房室分离，如心室搏动逆传，P波与QRS波群相关，房室分离消失，可出现1：1室房传导或2：l室房传导阻滞；④QRS波群时限超过0.14s，电轴左偏；⑤QRS波群形态，当表现为右束支传导阻滞时，具有以下的特征：V1导联呈单相或双相波（R>R′）；V6导联呈rS或QS；亦可呈左束支传导阻滞型；⑥全部胸导联QRS波群主波方向呈同向性：即全部向上或向下。
请阅读短文，并根据所读内容在文章后表格中的空格里填入一个最恰当的单词。 注意：每个空格只填一个单词。请将答案写在答题卡上相应题号的横线上。 Celebrating Sleep World Sleep Day, observed on 21 March, was created to bring attention to the growing number of sleep problems worldwide. Sleep is a natural part of human life, but many people in the modern world ignore its importance. As a result, sleep problems are increasingly common. In 2002, scientists at the University of Athens in Greece conducted a survey of over 35,000 people in 10 countries around the world, including China, Belgium and South Africa. Of the people that responded to the survey, 24 percent said that they did not sleep well, and based on their responses, 31.6 percent were diagnosed with insomnia and another 17.5 percent were diagnosed with borderline insomnia(失眠). In addition, 30.7 percent of survey respondents reported visiting a doctor for help with sleep problems and 11.6 per cent said that they felt very sleepy during the day. Overall, the survey found that many people suffer the effects of poor quality sleep, some examples of which are being unable to fall asleep and waking up in the middle of the night. The main factors causing these problems are pressure from school or work and a fast pace of life, but noise pollution and light pollution also interfere with sleep and contribute to poor quality sleep. The survey’s findings are particularly troubling because large numbers of people were found to have difficulty sleeping at night. The short-term effects of this are tiredness and trouble concentrating. If this happens for a long time, the risk of gaining weight and having a heart attack may increase. There are many things you can do to improve the quality of your sleep. First, you should have regular sleep habits. Try to go to bed and wake up around the same time each day. You also need to make your bedroom a cool, dark, quiet place to sleep so that heat, light and noise do not disturb you. At night, you should also avoid things that contain caffeine, such as chocolate, coffee, tea and many soft drinks, as caffeine may keep you from sleeping. Getting a good night’s sleep is important for everyone. By following the advice above, you can rest better at night and work better during the day. Title: Celebrating Sleep
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