1 Division of Cardiology, Department of Medicine, Nihon University School of Medicine, Tokyo, Japan; Division of Cardiology, Kawaguchi Municipal Medical Center, Kawaguchi, Japan.
2 Division of Cardiology, Department of Medicine, Nihon University School of Medicine, Tokyo, Japan. Electronic address: cocakochan@gmail.com.
3 Division of Cardiology, Kawaguchi Municipal Medical Center, Kawaguchi, Japan.
4 Division of Cardiology, Department of Medicine, Nihon University School of Medicine, Tokyo, Japan.
5 Section of Cardiac Electrophysiology, Division of Cardiology, University of California San Francisco, San Francisco, California.