The investigators evaluated the effects of neuromuscular electrical stimulation (NMES) therapy on functional capacity and oxidative stress in patients hospitalized for an episode of acute heart failure (AHF). The NMES therapy was used on top of the conventional rehabilitation program. After randomization the investigators followed the patients by measuring the evolution of functional capacity, oxidative stress and adverse events.

In this program the investigators will include patients with acute heart failure (AHF) with left ventricular ejection fraction (LVEF) lower than 50%, admitted to our clinic.

Patients prior to being included in this research will sign an informed consent form in two samples, one remaining with the patient. This form will contain the study protocol, risks, potential benefits as well as assuring patients that personal data will be used strictly for research purposes. The inclusion and exclusion criteria are presented below. The patients will be randomized into two groups: neuromuscular electrostimulation (NMES) therapy and conventional rehabilitation or a conventional rehabilitation program alone (respiratory gymnastics and strength / endurance exercises in bed).

Patients will receive optimal medical therapy for AHF according to current management guidelines. Patients will complete different questionnaires (Kansas, Beck for Depression). In the first phase, patients will be given a form with questions regarding notions about heart failure and cardiovascular recovery to assess the level of knowledge about their disease.

All patients included will perform the following:

• Clinical evaluation
• ECG
• Biological samples (including NT pro BNP, CK, oxidized LDL plus standard samples)
• Cardiac ultrasound
• 6-minute walk test (6MWT) The duration of NMES therapy will be equal to the duration of hospitalization. At the time of discharge, all patients will undergo a 6MWT and biological samples (NT pro BNP and oxidized LDL) and receive a cardiac rehabilitation program that they will follow at home. They will be given advice on initiating and maintaining a healthy diet, as well as discontinuing smoking if this risk factor is identified.

There will be a telephone visit at 30 days and the investigator will note the vital status and rehospitalizations.

Inclusion Criteria:

• patients with acute heart failure and a LVEF below 50% (echocardiography), admitted consecutively to the cardiology clinic of "Sfantul Pantelimon" Hospital, Bucharest

Exclusion Criteria:

• age under 18 years,
• acute coronary syndrome in the last month,
• recent myocardial revascularization (in the last 6 weeks),
• severe ischemic lesions at the level of the lower limbs,
• life-threatening arrhythmias,
• uncontrolled blood pressure,
• high-grade atrioventricular block,
• acute myocarditis,
• acute pericarditis,
• obstructive hypertrophic cardiomyopathy,
• acute systemic disease,
• deep vein thrombosis,
• severe uncorrected primary valvular disease,
• psychiatric disorders or marked cognitive impairment,
• active neoplastic disorders except basal or squamous cell carcinoma,
• other conditions that in the opinion of the investigator do not allow the participation to the study
• patient's refusal.

All the individual participant data can be available by email on request. This study is a part of a PhD thesis and a publication of the results will follow

The data is available from the present and 15 years from now

all the data can be accessed by request on email

After the patients were evaluated for inclusion in the study and after signing the informed consent form, they were randomized using the website www.randomization.com (1 complete randomized block). Considering our intervention protocol, it was not possible to blind the patients and/or the investigator who performed the electrostimulation. However, the other investigators who conducted the 6MWT and performed the randomization were blinded.