Inclusion Criteria:  eligible participants will be cardiac patients as those with myocardial infarction (6-weeks post-insult), coronary bypass graft surgery (CABG), cardiac patients with valve diseases, stable atrial fibrillation (AF), heart failure (HF)-I,II and III, with and resting ejection fraction (EF) greater than 50%.  Exclusion Criteria:  Cardiac patients with unstable angina, uncontrolled high blood pressure, unstable arrythmia, presence of complex ventricular arrhythmias, ST-segment depression ≥2mm from baseline during exercise testing or recovery, pacemaker patients will be all execluded from the study