This prospective, single-arm study aims to evaluate the effectiveness of Phase I cardiac rehabilitation based on remote electrocardiographic (ECG) monitoring in patients undergoing heart surgery. Eligible participants will receive a comprehensive cardiac rehabilitation program consisting of inpatient and home-based rehabilitation while wearing the MEMO Patch for remote ECG monitoring. Clinical outcomes, including functional exercise capacity, exercise performance, muscle strength, physical function, and health-related quality of life, will be evaluated before rehabilitation, before hospital discharge, and after completion of the rehabilitation program.