Exercise Prescription in Cardiac Rehabilitation Mediated by Autonomic Function

Inclusion Criteria: * Patients with Coronary artery disease and no heart failure criteria * Patients with non ischaemic heart failure and reduced left ventricle ejection fraction Exclusion Criteria: * patients with ongoing acute coronary syndrome * patients with ongoing acute decompensated heart failure * Severe valvular heart disease that might confound the relationship between exercise and autonomic function. * Severe arrhythmias (e.g., sustained ventricular tachycardia, atrial fibrillation with a rapid ventricular rate) that are symptomatic or untreated * Severe uncontrolled hypertension (e.g., systolic BP \> 180 mmHg or diastolic BP \> 110 mmHg) * Active infectious diseases or other significant acute medical illnesses (e.g., sepsis, active malignancy, acute kidney injury) * Pregnancy or lactation (to ensure safety during exercise interventions) * Significant cognitive impairment or mental illness (e.g., dementia, schizophrenia) that would impair the ability to follow exercise protocols or understand study instructions * nability to comply with study procedures due to any reason (e.g., language barriers, lack of informed consent) * Chronically immunocompromised states (e.g., HIV with CD4 count \< 200 cells/µL or on immunosuppressive therapy) * Presence of significant comorbidities such as advanced chronic obstructive pulmonary disease (COPD), kidney disease (e.g., stage 4-5 chronic kidney disease), or uncontrolled diabetes that would make exercise unsafe or confound the study outcomes * Critical limb ischemia, or severely symptomatic peripheral artery disease or claudication limiting functional capacity and response to exercise * Advanced chronic kidney disease (stage 4 or 5), due to contraindications with exercise * Severe anemia (hemoglobin \< 8 g/dL) or other blood disorders that affect exercise capacity * Inability to tolerate exercise due to other comorbidities or debility * individuals with known autonomic neuropathy (such as poorly controlled diabetes or neurodegenerative disorders) Specific Exclusion Criteria for Coronary Artery Disease (CAD) without Heart Failure Group: * Left ventricular ejection fraction (LVEF) \< 50% * Clinical/echocardiographic criteria of heart failure with oreserved ejection fraction. Specific Exclusion Criteria for Non-Ischemic Heart Failure with Reduced LVEF Group: * Ischemic heart disease or previous myocardial infarction * LVEF \> 40% * End-stage heart failure (e.g., patients on a heart transplant list, those with imminent need for mechanical circulatory support like LVAD). * Severe fluid overload that cannot be corrected