1. Division of Cardiac Surgery, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA
2. Leipzig Heart Centre, University Clinic of Cardiac Surgery, 02189 Leipzig, Germany
3. Department of Regenerative Medicine and Cell Biology, University of South Carolina, Charleston, SC 29425, USA
4. Cardiac Ultrasound Laboratory, Department of Cardiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA
5. Department of Biomedical Engineering, University of Arkansas, Fayetteville, AR 72701, USA
6. Department of Mechanical Engineering, University of Kentucky, Lexington, KY 40508, USA
7. Department of Surgery, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA