The purpose of this study is to assess functional capacity, quality of life and functioning of the autonomic nervous system in heart failure patients on beta-blocker treatment. The study hypothesis is that subjects who walk less distance, have lower quality of life and reduced heart rate variability during the six minute walk test.

Heart failure and its treatment result in symptoms such as pulmonary or systemic congestion causing impairment to the effort, psychological and social commitment, and impact on quality of life.

Inclusion Criteria:

• Both sexes
• Different etiologies of Heart Failure
• Functional class I - III (NYHA)
• Left ventricular ejection fraction (LVEF) ≤ 50%
• No history of previous cardiac surgery
• In return for medical evaluation at the Amelio Marques Clinic, Hospital de Clinicas, Federal University of Uberlândia scheduled for the period from October 2012 to January 2013
• Clinical stability observed by: heart rate, respiratory rate, blood pressure and arterial oxygen saturation

Exclusion Criteria:

• Bad cognition compromising the understanding of tests
• Physical disability that compromise the performance in walk test
• Aortic aneurysm or any aortic deformity
• Patients with signs or symptoms of transient myocardial ischemia with angina pectoris and/or class IV by the Canadian Cardiovascular Society Classification
• Anomalous pressure behavior with hypertension > 180/100 mmHg
• Orthostatic hypotension (decrease > 15 mmHg ) with symptoms
• Arrhythmia with presence of complex ventricular extra systoles
• Tachycardia sinus at rest (HR > 120 beats/min)
• Atrioventricular block of 2nd or 3rd degree
• Subjects with pacemakers or implantable cardioverter-defibrillator (ICD)
• Functional class IV by the New York Heart Association
• Chronic organ dysfunction such as renal failure, respiratory or liver disease
• Active neoplasia over the past five years
• Commitment as general weakness, fever, other limiting factors (psychological, musculoskeletal)
• Feeling sick before the beginning of the Six minute walk test: intolerable angina or dyspnea, cramps in legs, staggering gait, excessive sweating (diaphoresis), pallor or ashen skin or SpO2 below 85%
• Voluntary desire of the patient to withdraw from research

Heart failure patients routinely treated at the Amelio Marques Clinic, Hospital de Clínicas, Federal University of Uberlandia, who have scheduled a visit during the period of study and attends the criterias of the study will be included.

The sample will be a convenience, and included all patients who meet the study criteria.

The control group included healthy participants with the same gender and age of the chronic heart failure group.