1. Department of Cardiology, Second Affiliated Hospital of Shantou University Medical College, Shantou, Guangdong 515041, P.R. China
2. Department of Pediatrics, Second Affiliated Hospital of Shantou University Medical College, Shantou, Guangdong 515041, P.R. China
3. Department of Pediatrics, Maternal and Child Health Care Hospital of Pingshan District, Shenzhen, Guangdong 518000, P.R. China
4. Department of Pediatrics, Beijing Children's Hospital, Capital Medical Hospital, Beijing 100032, P.R. China