1. Division of Cardiology, Department of Internal Medicine, The Jikei University School of Medicine, Tokyo, Japan (S.Y., M.T., S. Matsuo, H.S., H.O., M. Yokoyama, R.I., K.T., K.Y., R.N., M.K., S. Miyanaga, M. Yoshimura, T.Y.).
2. Department of Cardiac Electrophysiology, Liverpool Heart & Chest Hospital (S. Mahida).
3. Liverpool Centre for Cardiovascular Science, United Kingdom (S. Mahida).