[Electrical myostimulation: improvement of quality of life, oxygen uptake and left ventricular function in chronic heart failure]. / Elektromyostimulation: Verbesserung von Lebensqualität, Sauerstoffaufnahme und linksventrikulärer Funktion bei chronischer Herzinsuffizienz.

AIM OF THE STUDY: Regular physical activity has found to be a strategy to increase exercise capacity in patients with chronic heart failure (CHF). Next to endurance training also electromyostimulation (EMS) of thigh and gluteal muscles results in an increased capacity in CHF patients. EMS therapy was either done by stimulating 8 major muscle groups involving also trunk and arm muscles (extended electromyostimulation (exEMS)) in comparison to EMS therapy limited to gluteal and leg muscles (limEMS). METHODS: 31 individuals completed the EMS training program. Stable CHF patients (NYHA class II-III) received either exEMS (18 patients, 11 males, mean age 59.8±13.8 years) or limEMS (13 patients, 10 males, 63.6±9.4 years). Training was performed for 10 weeks twice weekly for 20 min, the level of daily activity remained unchanged. Effects on exercise capacity, left ventricular function (EF - ejection fraction) and QoL (quality of life) were evaluated. RESULTS: QoL was found to be improved in all domains of the SF-36 questionnaire. In the exEMS group there was a significant improvement in the domain physical functioning (54.09±29.9 to 75.45±15.6, p=0.48) and emotional role (63.63±45.8 to 93.93±20.1 p=0.048). LimEMS group showed significant improvement in the domain vitality (37.5±6.9 to 52.8±12.5, p=0.02).There was a significant increase of oxygen uptake at aerobic threshold in all groups (exEMS: +29.6%, p<0.001; limEMS +17.5%, p<0.001). EF -increased from 36.94±8.6 to 42.36±9.1% (+14.7%, p=0.003) in the exEMS group (limEMS 37.7±3.6 to 40.3±5.9% [+6.9%, p=0.18]). CONCLUSION: EMS contributes to an improved quality of life and can improve oxygen uptake and EF in CHF. It may be an alternative therapy in CHF patients who are otherwise unable to undertake conventional forms of exercise training.

Effect of an anabolic steroid (Metenolon) on contractile performance of the chronically stimulated latissimus dorsi in sheep.

In 12 sheep the left latissimus dorsi muscles (LD) were conditioned by chronic electrostimulation with a pulse generator (Itrel, Medtronic). Six animals (group B) received a weekly intramuscular injection of an anabolic steroid (Metenolon). After 14 weeks the contraction parameters of the left LDs (group A and B) and right LDs (control group) were investigated. The increase in weight of the conditioned LDs was 11.07% (+/- 1.06%) in group A and 79.97% (+/- 40.8; P < 0.05) in group B. The force capacity under stimulation patterns which were just tetanic was 1.15 kp in group A and 4.13 kp in group B (P < 0.05); under supramaximal stimulation patterns it was 4.23 kp (A) and 6.0 kp (B) (P = ns). The force time relation (dF/dt) was 6.7 kp/s for the left LDs in group A versus 16.4 kp/s for the right LDs (P < 0.01); in group B it was 5.13 kp/s for the left LDs versus 15.8 kp/s for the control muscles (P < 0.05). The maximal force (Fmax) per 100 g muscle weight did not differ significantly (A: 2.42 kp/100 g; B: 2.52 kp/100 g). In conclusion, the LD muscles which were subjected to both anabolic therapy and electrical stimulation showed a significant increase in their force capacity due to an enormous increase in mass. Fibre type transformation was complete only in group B. No fibre deterioration was observable in either group. No anabolic side effects were detected in the animals. With the use of anabolic steroids, therefore, a clearer direct increase in contractility on the left ventricle should be expected ("squeezing" theory), as well as a contribution to reduction in wall tension and myocardial oxygen consumption, respectively, according to Laplace's Law (via the considerable increase in thickness).