Prof. Ken Okumura served as a Professor of Medicine at Hirosaki University School of Medicine from 1996 to 2016. He also served as a President of the Japanese Heart Rhythm Society (JHRS) from 2012 to 2016. He is now working at Saiseikai Kumamoto Hospital Cardiovascular Center, Japan, while providing the latest interventional treatments for cardiac arrhythmias especially catheter ablation of AF. His main interests include pharmacological and non-pharmacological treatments of cardiac arrhythmias, catheter ablation of persistent AF, and oral anticoagulant therapy for stroke prevention in AF especially in the elderly AF patients.