1. Advanced Heart Failure and Transplant Cardiology Section, Spectrum Health, Grand Rapids, Michigan
2. Division of Cardiology, Sarver Heart Center, University of Arizona, Tucson, Arizona
3. Advanced Heart Failure Section, Methodist Hospital, Houston, Texas
4. Frederick Meijer Heart and Vascular Institute, Grand Rapids, Michigan
5. Cardiothoracic Surgery Division, Spectrum Health, Grand Rapids, Michigan
6. Scania University Hospitals, Lund, Sweden.