1.Department of Cardiology|Second |Hospital, Jilin University,Changchun 130041| China;2.Department of Electrodiagnosis,Affiliated Hospital| Changchun University of Traditional Chinese Medicine,Changchun 130021,China;3.Department of Cardiology,China-Japan Union Hospital,Jilin University,Changchun 130033,China;4.Department of Electrodiagnosis,461 Division,No.208 Hospital of PLA,Changchun 130021,China