1. From the University of California, Los Angeles Cardiac Arrhythmia Center, University of California, Los Angeles Health System, David Geffen School of Medicine at University of California, Los Angeles (R.T., R.N., R.M., E.F.B., J.S.B., M.V., N.G.B., K.S.); St. Luke’s Health System/Texas Heart Institute, Houston (N.S.M.); and University of Texas Health Science Center, Houston (N.S.M.).