Low-frequency electromyostimulation (EMS) acts on the skeletal muscle abnormalities that aggravate intolerance to effort in patients with chronic heart failure (CHF). It improves the oxidative capacity of muscles and thus enhances aerobic performance and physical capacity to almost the same degree, as does conventional physical training. No local or hemodynamic intolerance has been reported, even in cases of severe CHF. However, the presence of a pacemaker is one of the relative contra-indications (prior evaluation of tolerance is required), while that of an implanted defibrillator is one of the absolute contra-indications. EMS is an alternative to physical effort training when the latter is impossible due to a high degree of deconditioning or because there is a contra-indication, which may be temporary, due to the risk of acute decompensation and/or rhythm troubles. EMS can also be used in patients waiting for a heart transplant or in CHF patients who are unwilling to engage in physical activities. As EMS is not expensive and easy to set up, its use is likely to develop in the future.