Shaorui Yi1, Linqiang Cong2, Yuqiang Zhang3. 1. Department of Cardiovascular Medicine, Yantai Affiliated Hospital, Binzhou Medical College, Liaocheng, China. 2. Department of Cardiology, Yantai Affiliated Hospital, Binzhou Medical College, Liaocheng, China. 3. Department of Electrocardiogram Room, East District of Liaocheng People's Hospital, Liaocheng, China - 93989852@qq.com.