Tetsuo Yamaguchi is trained at Saiseikai Nakatsu Hospital in Osaka Prefecture, which is famous for cardiac catheterization. After further training in general internal medicine and cardiology at Toranomon Hospital in 2008, since 2011 he has been mainly engaged in cardiovascular intervention (coronary artery and peripheral artery) at Musashino Red Cross Hospital. So far, he has treated more than 500 cases as the main operator. Graduated from Tokyo Medical and Dental University Graduate School in 2017 and obtained a doctorate in medicine. In July 2019, he was appointed as Chief of Internal Medicine at Toranomon Hospital Cardiovascular Center and Deputy Director of the Cardiac and Vascular Catheterization Center. He is also working on advanced care planning and palliative care in anticipation of the "heart failure pandemic".