Shortness of breath, fatigue, and exercise intolerance are clinical symptoms of chronic heart failure (CHF). Recent studies suggested that peripheral impairment was the major cause of clinical symptoms, and mechanism may be related to neuroendocrine impairment and vascular smooth muscle dysfunction. It results in increased peripheral resistance that may influence limb blood flow, muscle fitness and activities of daily.The purposes of this study are

1. to compare muscular strength, endurance, and perfusion of quadriceps between CHF patients and healthy controls by isokinetic test and near-infrared spectroscopy (NIRS) and difference in activities of daily living
2. to compare endothelium function between CHF patients and healthy control subjects
3. the relationship between endothelium function, muscular strength, endurance, perfusion, and metabolism of quadriceps.

Inclusion Criteria:

• Age 40-75 years
• Chronic heart failure: ejection fraction<40% and at stable condition
• Coronary Disease and dilated cardiomyopathy without heart failure
• Control group without diagnosis of any heart disease

Exclusion Criteria:

• Clinical diagnosis of neuromusculoskeletal , pulmonary, or other systemic diseases that may affect the testing of the study

Chronic Heart Failure Coronary Disease Dilated Cardiomyopathy Control group without diagnosis of any heart disease