Cardiovascular Center, Tufts Medical Center, Boston, Massachusetts. Electronic address: mkonstam@tuftsmedicalcenter.org. Cardiovascular Center, Tufts Medical Center, Boston, Massachusetts. University Cardiology Associates, Augusta, Georgia. Cardiovascular Division, University of Wisconsin, Madison, Wisconsin. Division of Cardiology, VA Greater Los Angeles, Los Angeles, California. Division of Cardiology, Drexel University, Philadelphia, Pennsylvania. Heart Center Research, Huntsville, Alabama. The Heart Institute, Mercy Hospital, Fairfield, Ohio. Division of Cardiology, Emory University, Atlanta, Georgia. Cardiovascular Medicine, Lahey Medical Center, Burlington, Massachusetts. Cardiovascular Institute, Miriam Hospital, Providence, Rhode Island. Advanced Cardiovascular Specialists, Shreveport, Louisiana. Center for Enhancing Quality of Life in Chronic Diseases, Indiana University School of Nursing, Indianapolis, Indiana. Cardiovascular Clinical Science Foundation, Boston, Massachusetts. Boston University School of Public Heath, Boston, Massachusetts.