1. From the McGuire VA Medical Center, Cardiology Division (J.F.H., K.K., J.P., A.J.M., E.J.L., Q.C., K.A.E.), and Virginia Commonwealth University (J.F.H., K,K., J.P., A.J.M., E.J.L., A.A., E.M., Q.C., R.C.K., N.N.H., L.R.T., K.A.E., M.A.W.), Richmond, VA.