1. Department of Medicine, Division of Cardiology, Emory University School of Medicine , 1364 Clifton Road, Atlanta, GA 30322 , USA
2. Georgia Institute of Technology, Department of Physics , 837 State St NW, Atlanta, GA 30332, USA
3. Department of Surgery, Division of Cardiovascular Surgery, Emory University School of Medicine, 1364 Clifton Road, Atlanta, GA 30322 , USA