1. Department of Internal Neurology, Baotou Medical School, Inner Mengolia Medical University, Inner Mengolia�014000, P.R.�China
2. Department of Emergency, The First Hospital of Qiqihar, Qiqihar, Heilongjiang 161005, P.R.�China
3. Department of ECG Room of Second Ward, The First Hospital of Qiqihar, Qiqihar, Heilongjiang 161005, P.R.�China
4. Department of Public Health, The First Hospital of Qiqihar, Qiqihar, Heilongjiang 161005, P.R.�China
5. Second Department of Breast Surgery, The First Hospital of Qiqihar, Qiqihar, Heilongjiang 161005, P.R.�China