Department of Cardiology, The First Hospital of China Medical University, Shenyang, Liaoning, PR China; Disease Control and Prevention of Liaoning Province, Shenyang, Liaoning, PR China. Department of Cardiovascular Ultrasound, The First Hospital of China Medical University, Shenyang, Liaoning, PR China. Disease Control and Prevention of Liaoning Province, Shenyang, Liaoning, PR China. Disease Control and Prevention of Tiexi District, Anshan, Liaoning, PR China. Disease Control and Prevention of Yuanbao District, Dandong, Liaoning, PR China. Disease Control and Prevention of Liaoyang County, Liaoyang, Liaoning, PR China. Disease Control and Prevention of Dawa District, Panjin, Liaoning, PR China. Department of Cardiology, The First Hospital of China Medical University, Shenyang, Liaoning, PR China. Electronic address: yxsun@cmu.edu.cn.