A Pilot Randomized Controlled Trial Comparing Core Exercise, Aerobic Exercise, and Combined Exercise in Patients Undergoing Phase II Cardiac Rehabilitation.

Inclusion Criteria: * Age over 18 years. * Diagnosed with myocardial infarction or heart failure with stable condition, and referred for participation in Phase II cardiac rehabilitation. * Able to regularly attend training sessions twice a week. Exclusion Criteria: * Underwent cardiac surgery within the past three months. * Presence of a pacemaker, defibrillator, or left ventricular assist device. * Cognitive impairment or dementia that prevents understanding or following training instructions. * Inability to complete cardiopulmonary exercise testing. * Pregnancy. * Contraindications to cardiac rehabilitation based on the American College of Sports Medicine (ACSM) guidelines, such as unstable angina, uncontrolled severe hypertension (resting systolic BP \>180 mmHg or diastolic BP \>110 mmHg), orthostatic hypotension (drop in BP \>20 mmHg upon position change), severe aortic stenosis, uncontrolled severe arrhythmia, decompensated heart failure, third-degree atrioventricular block, acute pericarditis or myocarditis, aortic dissection, acute pulmonary embolism, or other acute medical conditions such as infection or fever. * Refusal to participate in the study.