1. Division of Cardiovascular Medicine, Kumamoto Aging Research Institute, Kumamoto 860-8518, Japan
2. Division of Cardiovascular Medicine, Mizuno Heart Clinic, Koshi 861-1115, Japan
3. Department of Cardiovascular Medicine, Faculty of Life Science, Graduate School of Medical Sciences, Kumamoto University, Kumamoto 860-8556, Japan
4. Division of Cardiology, Department of Internal Medicine, The Jikei University School of Medicine, Tokyo 105-0003, Japan