1. From the Electrophysiology Section, Division of Cardiology, Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, CA (E.S.G., B.L.N.); Magnetecs Corp, Inglewood, CA (Y.S., Laszlo F., Leslie F., B.M., D.J.); the Department of Pathology and Laboratory Medicine, David Geffen School of Medicine at UCLA, Los Angeles, CA (M.C.F.); the Heart and Great Vessels Department, Umberto I Hospital, Sapienza University of Rome, Italy (B.L.N., C.G.); and St Jude Medical, St Paul, MN (S.J.K.).