1. Department of Pediatric Cardiology, The Affiliated Hospital of Southwest Medical University, Luzhou, Sichuan 646000, P.R. China
2. School of Nursing, Southwest Medical University, Luzhou, Sichuan 646000, P.R. China
3. Department of Pediatrics, Chengdu Women and Children's Central Hospital, Chengdu, Sichuan 610091, P.R. China
4. Department of Pediatrics, Xinqiao Hospital, Third Military Medical University, Chongqing 400037, P.R. China
5. Department of Pediatric Cardiology, West China Second University Hospital, Chengdu, Sichuan 610041, P.R. China