Heart failure (HF) has been associated with chronic deleterious effects on skeletal muscle, endocrine system, vasculature and sympathetic nervous system. These alterations have a significant impact on quality of life, leading to a reduction in functional capacity and limited symptoms, which involve dyspnea and fatigue. The investigators tested the hypothesis that hormonal anabolic deficiency associated with neurovascular alterations may worsen the prognosis of patients with heart failure.

One hundred and fifty six patients have been enrolled so far. Methods were as described below:

• Muscle sympathetic nerve activity (MSNA) was directly recorded from the peroneal nerve using the microneurography technique ;
• All patients underwent symptom-limited cardiopulmonary exercise test performed on a cycle ergometer, using a ramp protocol with workload increments of 5 or 10 Watts per minute;
• Body composition measurements were performed using dual-energy X-ray absorptiometry (DXA);
• Muscle strength was assessed by handgrip dynamometer using the mean value of three attempts;
• Blood samples were drawn in the morning after 12h overnight fasting. The laboratory tests included B-type natriuretic peptide (BNP; pg/mL) plasma level, serum sodium (mEq/L), serum potassium (mEq/L), creatinine (mg/dL), haemoglobin level (g/dL), high-sensitivity C-reactive protein (CRP; mg/L), lipid profile (triglyceride, total cholesterol, high-density lipoprotein, and low-density lipoprotein; mg/dL), and fasting glucose (mg/dL). Blood sample to assess hormone plasma levels were also drawn at the same time: total testosterone (TT), free testosterone (FT), sex hormone binding globulin (SHBG), dehydroepiandrosterone sulfate (DHEAS), luteinizing hormone (LH), follicle-stimulating hormone (FSH), thyroid stimulating hormone (TSH) and insulin-like growth factor 1 (IGF1).

Inclusion Criteria:

• age between 18 and 65 years old;
• at least1 year of diagnosed HF;
• left ventricular ejection fraction (LVEF) lower than 40% measured by echocardiography;
• non-ischaemic and ischaemic aetiologies;
• compensated HF with optimal medication for at least 3 months prior the study;
• New York Heart Association (NYHA) class of I to IV.

Exclusion Criteria:

• patients with autonomic diabetic neuropathy;
• patients with chronic renal failure with haemodialysis;
• heart transplantation;
• presence of pacemaker;
• patients with muscular dystrophy (i.e. Duchenne muscular dystrophy);
• patients submitted to any hormonal treatment;
• history of cancer;
• ongoing infection;
• myocardial infarction with percutaneous coronary intervention or revascularization 6 months prior to the study entry.

Patients with heart failure recruited at Clinical Unit of Myocardiopathy at General Hospital of the University of São Paulo Medical School (UNCAR/HC-FMUSP).