1. From the Division of Cardiovascular Diseases (T.A., F.H.S.-K., A.D.C., P.S., A.R.-C., C.v.d.W., D.E.D., J.B., T.K., J.S.-J., V.K.S.), Mayo Clinic College of Medicine, Rochester, MN; Division of Sleep Medicine (S.P.), University of Minnesota, Minneapolis, MN.