This trial is to evaluate two types of electrical muscle Stimulation (EMS) stimulation (low intensity "conventional stimulation" vs. high intensity "Russian" stimulation) of legs in comparison with a control group without EMS in a cohort of elderly patients with severe deconditioning after CHF decompensation.

BACKGROUND:

Congestive heart failure (CHF) is increasingly prevalent worldwide and is associated with significant morbidity and mortality. Poor exercise capacity is well known as a risk factor for poor prognosis. The deconditioning is mainly associated with a decrease in leg muscle mass and loss of leg strength as well as loss of muscle endurance. This affects especially elderly patients. To improve this condition in CHF electrical muscle stimulation (EMS) is a suitable method of training, which hardly affects the heart. However, most EMS existing stimulation protocols are uncomfortable and not user-friendly, especially for elderly patients. The Russian space medicine has many years' experience in specific EMS stimulation protocols, which are well tolerated by cosmonauts for hours even during working activities. Therefore, a research project has been established between the Russian Academy of Sciences (Laboratory for Biomedical Problems) and the ARTORG Research Center for Biomedical Engineering to study the effects of new developed EMS procedures in elderly persons.

Aims:

The aim of trial is to evaluate two types of EMS stimulation (low intensity "conventional stimulation" vs. high intensity "Russian" stimulation) of legs in comparison with a control group without EMS in a cohort of elderly patients with severe deconditioning after CHF decompensation.

METHOTOLOGY:

This prospective, randomized controlled study will use commercially available electronic stimulator devices (Medel GmbH, Hamburg, Germany) for EMS. For the "Russian" stimulation, an especial developed stimulator (Amplidin-EST No.5) will be used for frequency modulation of the stimulation impulse, which is supposed to make stimulation sensation more comfortable. Supervised EMS training will be performed 5 times per week (weekdays) during 30 minutes over a period of 6 weeks in elderly deconditioned CHF patients, starting at the Kantonsspital Olten during the hospitalisation and continued at home. We will include 20 patients in each group (20 in control group, 20 in low intensity "conventional group and 20 in high intensity "Russian" group). The control group was preformed to exclude an attention bias in the study results. The primary endpoint of the study is the difference in maximum oxygen uptake (peak VO2) and in 6 minutes walking distance between baseline and after 6-weeks EMS training in all groups (high intensity vs low intensity vs control). The follow-up period is planned for 2 years.

POTENTIAL SIGNIFICANCE:

Exercise capacity and quality of life in severely deconditioned patients with CHF is poor and life expectancy is low. While the possibilities to improve the poor condition and function of the heart by pharmaceutical therapies are limited, there is potential to improve the condition of the peripheral muscles by exercise training. However, a successful aerobic training is rarely feasible in these patients. Therefore, EMS training may prove to be ideal tool to improve leg muscle mass and function of elderly patients. Because, CHF patients do not tolerate most of the existing EMS stimulation protocols, we have developed a new EMS stimulation protocol. The application is virtually painless and therefore well tolerated over hours due to a sophisticated stimulation protocol. Therefore, we hope that, this especial for elderly CHF patients developed training protocol, may improve their daily activity as well as their quality of life.

Inclusion Criteria:

• age ≥ 60 years
• hospitalized due to heart failure
• left ventricular ejection fraction ≤ 40%
• NYHA class II to IV
• willingness to complete the 6-week EMS training programme
• tolerability of the electrical stimulation
• provision of informed consent

Exclusion Criteria:

• severe neuromuscular or oncologic diseases with inability to perform exercise testing and EMS training
• inotropic intravenous agents used (≤10 days)
• implanted pacemaker/ICD
• unstable angina
• severe uncontrolled arrhythmias
• patients with severe pulmonary limitation (Tiffeneau ratio <70%, or vital capacity <70% of predicted value)