1 Electrophysiology Section, Division of Cardiology, Department of Medicine, University of California-San Francisco, San Francisco, California, USA.
2 Interventional Cardiology Section, Division of Cardiology, Department of Medicine, University of California-San Francisco, San Francisco, California, USA.
3 Electrophysiology Section, Division of Cardiology, Department of Medicine, University of California-San Francisco, San Francisco, California, USA. Electronic address: edward.gerstenfeld@ucsf.edu.