1. Department of Medicine Olive View‐UCLA Medical Center Los Angeles California USA
2. Department of Medicine, Division of Cardiology David Geffen School of Medicine at UCLA Los Angeles California USA
3. Department of Medicine, Division of Cardiology Veterans Affairs Greater Los Angeles Healthcare System and UCLA Los Angeles California USA
4. Exercise Physiology Research Laboratory, Departments of Medicine and Physiology David Geffen School of Medicine at UCLA Los Angeles California USA
5. UCLA Cardiac Arrhythmia Center David Geffen School of Medicine at UCLA Los Angeles California USA