1 Departments of Cardiovascular Medicine (Division of Heart Rhythm Services), Pediatric and Adolescent Medicine (Division of Pediatric Cardiology), and Molecular Pharmacology & Experimental Therapeutics (Windland Smith Rice Sudden Death Genomics Laboratory), Mayo Clinic, Rochester, Minnesota. Electronic address: ackerman.michael@mayo.edu.
2 Department of Cardiovascular Medicine (Clinician-Investigator Training Program), Mayo Clinic, Rochester, Minnesota.