1. From the Division of Pediatric Cardiology, Department of Pediatric and Adolescent Medicine (J.H.A., M.J.A.), Department of Molecular Pharmacology and Experimental Therapeutics/Windland Smith Rice Sudden Death Genomics Laboratory (D.J.T., M.L.W., M.J.A.), and Division of Cardiovascular Diseases, Department of Medicine, Mayo Clinic, Rochester, MN (M.J.A.).