1. Scottish National Advanced Heart Failure Service, Golden Jubilee National Hospital, Clydebank, United Kingdom (R.S.G.).
2. Massachusetts General Hospital, Boston (J.P.S.).
3. Eastern Slovakia Institute for Cardiac and Vascular Diseases, Kosice, Slovakia (B.S.).
4. St. Bernards Heart and Vascular Center, Jonesboro, AR (D.G.N.).
5. Golden Heart Medical, Rosemead, CA (M.C.).
6. Cardiology Consultants of Philadelphia, PA (C.S.).
7. Boston Scientific, Marlborough, MA (P.H.T., Q.A., S.W., E.F.H., Y.Z.).
8. Penn State Milton S. Hershey Medical Center, Hershey, PA (J.P.B.).