1. From the Heart Rhythm Institute and Department of Medicine, University of Oklahoma Health Sciences Center (K.Y., H.N., A.I., T.S., R.L., W.M.J.), Department of Pathology, Veterans Administration Medical Center (J.V.P.), Oklahoma City, Oklahoma; Hospital Cantonal De Geneve (D.C.S.) and Endosense SA (H.L., G.L., N.A.), Geneva, Switzerland.