1. Division of Cardiology, Mercy Heart Hospital, Springfield, MO 65804, USA
2. Division of Cardiology, University of Missouri, Columbia, MO 65212, USA
3. Division of Cardiology, Yuma Regional Medical Center, Yuma, AZ 85364, USA
4. Division of Cardiology, Ascension Borgess Hospital, Kalamazoo, MI 49048, USA
5. Homer Stryker M.D. School of Medicine, Western Michigan University, Kalamazoo, MI 49008, USA