SUrvey of Guideline Adherence for Treatment of Systolic Heart Failure in Real World (SUGAR): a multi-center, retrospective, observational study. oleh Byung-Su Yoo, Jaewon Oh, Bum-Kee Hong, Dae-Hee Shin, Jang-Ho Bae, Dong Heon Yang, Wan-Joo Shim, Hyung-Seop Kim, Su-Hong Kim, Jin-Oh Choi, Woo-Jung Chun, Choong-Won Go, Hyun-Jae Kang, Sang Hong Baek, Jang-Hyun Cho, Suk-Keun Hong, Joon-Han Shin, Seok-Kyu Oh, Wook-Bum Pyun, Jun Kwan, Young-Joon Hong, Jin-Ok Jeong, Seok-Min Kang, Dong-Ju Choi, SUGAR Study