1 Texas Cardiac Arrhythmia Institute, St David's Medical Center, Austin, Texas, USA.
2 Texas Cardiac Arrhythmia Institute, St David's Medical Center, Austin, Texas, USA; Department of Biomedicine and Prevention, Division of Cardiology, University of Tor Vergata, Rome, Italy; Interventional Electrophysiology, Scripps Clinic, San Diego, California, USA; Department of Internal Medicine, Metro Health Medical Center, Case Western Reserve University School of Medicine, Cleveland, Ohio, USA. Electronic address: [email protected].