The purpose of this study is to determine if addition of low frequency electro-myo-stimulation to cardiac rehabilitation is effective to improve exercise capacity and/or muscular strength in chronic heart failure patients.

In chronic heart failure, low exercise capacity is due, in part, to peripheral muscles abnormalities. Exercise training performed during cardiac rehabilitation improves exercise tolerance measured by cardiopulmonary exercise test. Low frequency electromyostimulation (EMS) was proposed as an alternative to exercise training (ET) in this population.

However, the effectiveness of the combination (EMS +ET) compared with ET alone is not proved. The main objective is to compare exercise capacity judged by peak VO2 after treatment by ET alone versus EMS+ET. The secondary end points are results on sub maximal parameters, muscular resistance, quality of life and effectiveness regarding clinical sub-groups.

This study is a controlled, randomized, multicentric (14 centres) designed to include 90 patients by group in two years period. Inclusion criteria are: CHF patients , NYHA class II to IIIb, with LVEF < 40% referred to complete a cardiac rehabilitation program.

All the patients benefit from a comprehensive cardiac rehabilitation program including educational program, therapeutical optimisation and exercise training for 20 sessions, 3 to 5 days a week. The group of patients randomized for additional EMS has 20 sessions of 1 hour electrical quadricipital myostimulation.

Inclusion Criteria:

• age from 18 to 75 yo
• stable Chronic Heart Failure (CHF) under "optimal" treatment since at least 1 week
• NYHA functional class II to IIIb
• left ventricular ejection fraction < 40%
• cardiopulmonary exercise test feasible
• whatever etiology of heart failure
• age of heart failure ≥ 3 months.
• have signed the consent document to participate in the study

Exclusion Criteria:

• previous treatment by functional electrical myo stimulation
• recent acute heart failure or inotropic intravenous agents used (< 10 days)
• recent coronary angioplasty (< 10 days)
• cardiac surgery < 1 month
• valvular disease requiring surgical treatment
• uncontrolled hypertension (≥ systolic 180 and/or diastolic 110 mmHg)
• severe respiratory insufficiency (VEMS < 1000 ml)
• pregnancy
• Automatic implantable defibrillator
• pace-makers : cardiac stimulation dependence or not known
• incapacity to achieve 6 min walk test and/or exercise testing
• absolute contra-indication to exercise test and/or exercise training
• myocarditis or pericarditis
• uncontrolled ventricular arrhythmias
• Obesity (BMI ≥ 35)
• known and documented peripheral myopathy
• participation to another study protocol
• patient incapable of giving consent