1. Department of Cardiology, Daping Hospital, The Third Military Medical University, Chongqing City 400042, People's Republic of China
2. Department of Pediatrics, Georgetown University Medical Center, Washington D.C. 20007, U.S.A.
3. Department of Medicine, Georgetown University Medical Center, Washington D.C. 20007, U.S.A.
4. Department of Physiology and Biophysics, Georgetown University Medical Center, Washington D.C. 20007, U.S.A.