1 Electrophysiology, Harvard Medical School, Boston, MA, USA.
2 Texas Cardiac Arrhythmia Institute, St. David's Medical Center, 3000 N. I-35, Suite 720, Austin, TX 78705, USA.
3 Interventional Electrophysiology, Scripps Clinic, 10666 N Torrey Pines Rd, La Jolla, CA 92037, USA.
4 Department of Internal Medicine, Metro Health Medical Center, Case Western Reserve University School of Medicine, 2500 Metrohealth Dr, Cleveland, OH 44109, USA.
5 Department of Biomedicine and Prevention, Division of Cardiology, University of Tor Vergata, Via Montpellier, 1, Rome 00133, Italy.