Study aim: Comparison of the Effects of Microlearning and Teach-back Methods in Discharge Education on Self-efficacy and Quality of Life among Patients Hospitalized in the Cardiac Care Unit Design: A three-arm parallel randomized controlled trial with a 1:1:1 allocation ratio will be conducted. Variable block randomization will be used. Participants and the intervention provider cannot be blinded; however, data analysis will be performed by a person unaware of group allocation. Clinical trial phase: Not applicable. Settings and conduct: The study will be conducted in cardiac care units of teaching hospitals affiliated with Shahid Beheshti University of Medical Sciences in Tehran. Outcomes will be assessed at baseline, one month, and two months after discharge. Participants/Inclusion and exclusion criteria: Participants will include patients aged 18 years and older with a confirmed diagnosis of acute coronary syndrome, hospitalized in the coronary care unit for at least 24 hours, who are fully conscious, able to communicate verbally, and have access to a smartphone. Patients with cognitive impairment or severe psychiatric illness, hemodynamic instability, transfer to another healthcare facility, failure to complete the study, or death during the study will be excluded. Intervention groups: The microlearning group will receive 14 short educational units over 14 consecutive days after discharge. The teach back group will receive the same educational content during three inpatient sessions and one discharge session using the teach back method. The usual care group will receive routine discharge education. Main outcome variables: Cardiac self-efficacy; quality of life