In cardiac surgery patients, decreased Respiratory Muscle Strength has been associated with decreased functional capacity and has contributed to a prolonged period of recovery of lung function and the occurrence of physical deconditioning, which can last for several weeks. Respiratory repercussions also generate changes in RMS, as well as changes in lung volumes and capacities, alveolar dysfunction, depression of central respiratory stimulation, and mechanical disorders of thoracic function. In addition, it is known that most cardiac surgery patients present with episodes of muscle weakness in the preoperative period, which is accentuated after the surgical procedure. However, this muscle weakness is more noticeable in the respiratory muscles than in the peripheral muscles, although the latter muscles are also inactive.After coronary artery bypass graft (CABG) surgery, Postoperative pulmonary complications [PPCs] are a major source of morbidity and mortality, and increase length of hospital stay and resource utilization. Post operative inspiratory muscle training (IMT) efficacy in reducing the incidence of PPCs in high-risk patients undergoing CABG surgery has not yet been determined. Therefore, the present study is to determine the efficacy of Powerbreathe medic plus device on maximal inspiratory pressure, functional capacity and quality of life in Coronary Artery Bypass Graft Patients.