1. Nankai Hospital, Tianjin Medical University, Tianjin, China
2. Department of cardiology, Nankai Hospital, Tianjin, China
3. Department of Obstetrics, The First Teaching Hospital of Tianjin University of Traditional Chinese Medicine, Tianjin, China
4. Institute of Cardiovascular Disease and Heart Center, Characteristic Medical Center of the Chinese People’s Armed Police Force, Tianjin, China
5. Department of Cardiology, Tianjin Economic-Technological Development Area (TEDA) International Cardiovascular Hospital, Tianjin, China