The effect of functional electrical stimulation of the legs on cardiopulmonary function and quality of life in patients with chronic heart failure: A systematic review and meta-analysis

Introduction

Functional electrical stimulation is important for the rehabilitation of patients with chronic heart failure. This meta-analysis of randomized controlled trials compared the efficacy of functional electrical stimulation versus conventional exercise training or placebo in patients with chronic heart failure.

Methods

Studies were searched through PubMed, Embase, and the Cochrane Library databases up to 1 November 2023. The outcomes were cardiopulmonary function index (6-minute walking distance), peak oxygen consumption, and Minnesota Heart Failure Life Questionnaire quality of life scores. A subgroup analysis was conducted according to the ejection fraction. The 95% confidence interval and mean difference represented the outcome of the effect size.

Results

Seventeen studies involving 732 participants were included. Compared with the control, functional electrical stimulation significantly improved peak oxygen consumption (MD = 2.84 ml/kg/min, 95% Cl: 1.99-3.68 ml/kg/min), increased 6-minute walking distance (MD = 49.52 m, 95% Cl: 22.61-76.43 m), and improved the life quality scores (MD = -12.86, 95% Cl: -17.48 to -7.88). Compared with functional electrical stimulation, exercise training also improved peak oxygen consumption (MD = -0.94 ml/kg/min-1, 95% Cl: -1.36 to -0.52 ml/kg/min), and the quality of life (QoL, MD = 0.66, 95% Cl: 0.34-0.98, p < 0.05, I 2 = 38%), but the result of 6-minute walking distance (MD = -6.97 m, 95% Cl: -18.32 to -4.38 m) did not show a difference. Further subgroup analysis showed that outcomes including the above, significantly improved under the functional electrical stimulationfor both HF patients with reduced ejection fraction and HF patients with preserved ejection fraction patients, but difference is insignificant of the results between groups of aerobic exercise and functional electrical stimulationacted on patients with HF patients with reduced ejection fraction.

Conclusions

Our study demonstrates that compared with placebo, functional electrical stimulation benefits the patients with chronic heart failure on cardiopulmonary function and quality of life. Furthermore, HF patients with reduced ejection fraction patients benefit more from functional electrical stimulation than HF patients with reduced ejection fraction patients. Therefore, functional electrical stimulation is a promising complementary therapy for patients with chronic heart failure.

Association between skeletal muscle and left ventricular mass in patients with hyperthyroidism

Objective

This study aims to investigate the relationship between skeletal muscle and left ventricular mass (LVM) in patients with hyperthyroidism, providing theoretical and data-based foundations for further research on the interaction between secondary muscle atrophy and cardiac remodeling.

Methods

A retrospective data collection was conducted, including 136 patients with hyperthyroidism (Study group) and 50 healthy participants (control group). The Study group was further divided into Group A (high LVM) and Group B (low LVM) based on LVM size. Multiple linear regression analysis was performed to examine the correlation between skeletal muscle and LVM, with model evaluation. Based on the results, further nonlinear regression analysis was conducted to explore the detailed relationship between skeletal muscle and LVM.

Results

Compared to the control group, the Study group exhibited significantly lower LVM, skeletal muscle mass index (SMI), and skeletal muscle mass (SMM) (P<0.05). Within the subgroups, Group A had significantly higher SMI, SMM, and hand grip strength compared to Group B (P<0.05). The results of the multiple linear regression showed a certain correlation between SMI (β=0.60, P=0.042, 95% CI=0.02~1.17) and hand grip strength (β=0.34, P=0.045, 95% CI=0.01~0.67) with LVM. However, the residuals of the multiple regression did not follow a normal distribution (K-S=2.50, P<0.01). Further results from a generalized linear model and structural equation modeling regression also demonstrated a correlation between SMI (β=0.60, P=0.040, 95% CI=0.03~1.17) (β=0.60, P=0.042, 95% CI=0.02~1.17) and hand grip strength (β=0.34, P=0.043, 95% CI=0.01~0.67) (β=0.34, P=0.045, 95% CI=0.01~0.67) with LVM.

Conclusion

Patients with hyperthyroidism may exhibit simultaneous decreases in LVM, SMM, and SMI. The LVM in patients is correlated with SMM and hand grip strength, highlighting the need for further exploration of the causal relationship and underlying mechanisms. These findings provide a basis for the prevention and treatment of secondary sarcopenia and cardiac pathology in patients with hyperthyroidism.

In-hospital electrical muscle stimulation for patients early after heart failure decompensation: results from a prospective randomised controlled pilot trial

Background

Electrical muscle stimulation (EMS) is being evaluated as a possible alternative to exercise training to improve functional capacity in severely deconditioned patients with heart failure (HF). However, there is insufficient data on delayed effects of EMS starting early after decompensation. The aim of this study was to determine the impact of a short inpatient EMS intervention in severely deconditioned patients with HF on functional capacity and quality of life (QoL) over a follow-up period of 1 month.

Methods

This is a prospective randomised sham-controlled pilot study. 45 patients hospitalised for decompensated systolic HF (58% men, mean age 66.4±10.2 years) were randomised to EMS (n=22) or sham stimulation (n=23) of lower limbs starting within 3 days after admission. The intervention included 7–10 sessions lasting from 30 to 90 min. The 6-minute walking test distance (6-MWTD), Duke Activity Status Index (DASI) and Minnesota Living with Heart Failure Questionnaire (MLHFQ) were evaluated at baseline, discharge and after 1 month.

Results

All patients completed the programme with good EMS tolerance. 37 patients were included in the final analysis. At discharge, 6-MWTD improved from 206,1±61,3 to 299.5±91 m, DASI from 12.1±5.6 to 18.3±7.2 and MLHFQ from 55.6±8.5 to 34.2±9 with EMS compared with smaller improvements in the sham group (p<0.05 for all). One month after discharge, improvements in the EMS group remained significant for MLHFQ (p=0.004) and DASI (p=0.042) and statistically non-significant for 6-MWTD compared with the sham group.

Conclusions

Short-term in-hospital EMS leads to improvements in functional capacity and QoL in selected patients early after HF decompensation that are retained over 1 month after discharge and therefore may serve as initial intervention to improve physical capacity or as a bridge to further conventional exercise training. Larger studies are required to evaluate individual responses to an early initiation of EMS in decompensated HF as well as long-term effects.

Validación de constructo de la escala Zung en pacientes con falla cardíaca

Introducción: La escala Zung para depresión ha sido previamente utilizada en pacientes con falla cardíaca; sin embargo, en nuestro conocimiento no se encuentra evidencia de su validez para la versión en español y su uso en población adulta con falla cardíaca en Colombia. Objetivo: Determinar la validez de constructo de la escala Zung para depresión en su versión original y proponer una versión abreviada para pacientes adultos con falla cardíaca. Materiales y Métodos: Estudio de corte transversal, realizado en 200 pacientes de una clínica de falla y trasplante cardiaco, en quienes se aplicó Zung Self-Rating Depression Scale. Se evaluó la consistencia interna por medio del alfa de Cronbach y el  análisis factorial fue utilizado para identificar las dimensiones del instrumento. Resultados: La consistencia interna de la versión original de la escala (20 ítems) fue de α=0.811. El análisis de factores mostró una estructura compuesta por tres factores que explican el 51.59% de la varianza total. La nueva versión abreviada (13 ítems) obtuvo un α=0.819 y los ítems correlacionaron con un único factor que explicó el 33.54% de la varianza total. Discusión: Nuestros hallazgos son similares a los encontrados por otros autores en diferentes poblaciones a la estudiada. Conclusiones: Se evidenció validez de constructo tanto para la escala Zung para depresión en su versión original como para la abreviada creada en la población estudiada. Sin embargo, se requieren estudios adicionales que verifiquen estos hallazgos en una muestra representativa y que otros aspectos de la psicometría sean evaluados.

The effectiveness of functional electrical stimulation of the legs in patients with heart failure: A systematic review and meta-analysis of randomized controlled trials

OBJECTIVE

To investigate the effectiveness of functional electrical stimulation of the legs in patients with heart failure.

METHODS

Data were obtained from PubMed, Cochrane Library, and Embase databases until August 12, 2021. We included randomized controlled trials that evaluated the effects of functional electrical stimulation applied to the legs of patients with heart failure, namely changes in cardiopulmonary function, muscle strength, and quality of life.

RESULTS

In total, 14 randomized controlled trials (consisting of 518 patients) were included in our article. Pooled estimates demonstrated that functional electrical stimulation significantly improved peak oxygen consumption (peak VO₂; standardized mean difference = 0.33, 95% confidence interval = 0.07-0.59, eight randomized controlled trials, n = 321), 6-min walking distance (mean difference = 48.03 m, 95% confidence interval = 28.50-67.57 m, 10 randomized controlled trials, n = 380), and Minnesota Living with Heart Failure Questionnaire quality of life score (mean difference =  - 8.23, 95% confidence interval =  - 12.64 to - 3.83, nine randomized controlled trials, n = 383). Muscle strength of lower extremities was not significantly improved in the functional electrical stimulation group compared with that in the control group (standardized mean difference = 0.26, 95% confidence interval =  - 0.18 to 0.71, five randomized controlled trials, n = 218). Furthermore, the subgroup analysis revealed that functional electrical stimulation significantly improved peak VO₂, 6-min walking distance, and Minnesota Living with Heart Failure Questionnaire quality of life score in the heart failure with reduced ejection fraction and heart failure with preserved ejection fraction subgroups.

CONCLUSION

Functional electrical stimulation can effectively improve the cardiopulmonary function and quality of life in patients with heart failure. However, functional electrical stimulation did not significantly improve muscle strength in the legs.

Real-world experience of feasibility and efficacy of electrical muscle stimulation in elderly patients with acute heart failure: A randomized controlled study

BACKGROUND

Reduced aerobic capacity and deconditioning contributes to morbidity and mortality in elderly acute heart failure (AHF) patients. Electrical muscle stimulation (EMS) has shown to be a suitable alternative to exercise in AHF. However, feasibility and efficacy are unknown in a real-world setting.

METHODS

This is a prospective, open label blinded, randomized, controlled study, investigating feasibility and efficacy of high-intensity versus low-intensity EMS versus controls in elderly AHF patients. Patients and investigators were blinded to the intervention. EMS was offered to > 60 years old AHF patients, initiated during hospitalization and continued at home. Outcome measures included changes in 6-min walking test distance (6-MWTD), functional capacity and quality-of-life at 3 and 6 weeks.

RESULTS

Among 97 consecutive AHF patients (78.1 ± 9.4 years, 42.3% females), 60 (61.9%) were eligible for EMS. Of these, 27 provided written informed consent and were randomly assigned to high-intensity (n = 10), low-intensity EMS (n = 9) and controls (n = 8). 13/27 completed the intervention. Main reason for dropouts was intolerance of the overall intervention burden. MACE occurred in 5 and were not associated with the study. EMS groups showed significant improvement of 6-MWTD (controls vs low-intensity p = 0.018) and of independence in daily living (for both p < 0.05).

CONCLUSIONS

Changes in 6-MWTD suggest efficacy of EMS. Whereas all tolerated EMS well, the burden of study intervention was too high and resulted in a consent rate of <50% and high dropouts, which limit the interpretability of our data. Less demanding EMS protocols are required to evaluate the full potential of EMS in elderly AHF patients.

The Combined Effect of Neuromuscular Electrical Stimulation and Insulin Therapy on Glycated Hemoglobin Concentrations, Lipid Profiles and Hemodynamic Parameters in Patients with Type-2-Diabetes and Hemiplegia Related to Ischemic Stroke: A Pilot Study

Type-2-diabetes mellitus (T2DM) is a global problem of medical, social and economic consequences. Physical activity is a vital therapy in patients with T2DM, but some of them cannot exercise for various reasons. The purpose of our pilot study was to determine whether a combination of neuromuscular electrostimulation (NMES) and insulin therapy could improve the management of T2DM patients with hemiplegia caused by an ischemic stroke. Fifteen immobile patients with T2DM on insulin therapy were enrolled in the study. NMES was applied to their lower limbs for 60 min, 5 days a week, over a period of 12 weeks. The intervention caused statistically significant reductions in the blood concentrations of glycated hemoglobin, total cholesterol and low-density cholesterol in the participants. Furthermore, systolic and diastolic blood pressure levels were significantly lower. More randomized clinical trials are needed to accurately measure the effect of NMES on T2DM treatment and to determine whether it can be an alternative for physical activity for immobile patients with T2DM.

Estimulação elétrica funcional associada ao treinamento combinado pós-CRM: ensaio clínico randomizado

RESUMO Os efeitos da adição da estimulação elétrica funcional (EEF) ao treinamento aeróbico e resistido (treino combinado) de curto prazo em pacientes submetidos à cirurgia de revascularização do miocárdio (CRM) ainda não foram estabelecidos. O objetivo do presente estudo é avaliar o impacto da adição da EEF ao treino combinado no fluxo arterial periférico, na capacidade funcional e na qualidade de vida de pacientes pós-CRM participantes de um programa de reabilitação cardíaca - Fase II. Trata-se de um ensaio clínico randomizado, duplo cego, composto por 17 pacientes (54,8±10,5 anos, 12 homens) randomizados ou em grupo intervenção (GI, n=8,) submetido à EEF no músculo quadríceps associada ao treino combinado, ou em grupo sham (GS, n=9), que realizou a EEF sham em associação ao treino combinado. Os desfechos avaliados foram: fluxo arterial periférico (índice tornozelo-braquial), capacidade funcional (distância percorrida no teste de caminhada de seis minutos - DTC6M) e qualidade de vida (questionário MacNew). Na comparação entre os grupos, o aumento do índice tornozelo-braquial (GI: 0,14±0,08 mmHg vs. GC: 0,05±0,04 mmHg; p=0,020) e do escore do domínio global do questionário MacNew (GI: 1,1±0,3 pontos vs. GC: 0,6±0,4 pontos; p=0,020) foi maior no GI. Entretanto, não foi observada diferença entre os grupos para a DTC6M (GI: 130,9±73,7 m vs. GS: 73,7±32,6 m; p=0,072). A adição da EEF, durante curto período, potencializou os efeitos do exercício aeróbico e resistido sobre o fluxo arterial periférico e a qualidade de vida em pacientes pós CRM em Fase II da reabilitação cardíaca.

Tai Chi exercise and functional electrical stimulation of lower limb muscles for rehabilitation in older adults with chronic systolic heart failure: a non-randomized clinical trial

Exercise-based training decreases hospitalizations in heart failure patients but such patients have exercise intolerance. The objectives of the study were to evaluate the effect of 12 weeks of Tai Chi exercise and lower limb muscles' functional electrical stimulation in older chronic heart failure adults. A total of 1,084 older adults with chronic systolic heart failure were included in a non-randomized clinical trial (n=271 per group). The control group did not receive any kind of intervention, one group received functional electrical stimulation of lower limb muscles (FES group), another group practiced Tai Chi exercise (TCE group), and another received functional electrical stimulation of lower limb muscles and practiced Tai Chi exercise (FES & TCE group). Quality of life and cardiorespiratory functions of all patients were evaluated. Compared to the control group, only FES group had increased Kansas City Cardiomyopathy Questionnaire (KCCQ) score (P<0.0001, q=9.06), only the TCE group had decreased heart rate (P<0.0001, q=5.72), and decreased peak oxygen consumption was reported in the TCE group (P<0.0001, q=9.15) and FES & TCE group (P<0.0001, q=10.69). FES of lower limb muscles and Tai Chi exercise can recover the quality of life and cardiorespiratory functions of older chronic heart failure adults (trial registration: Research Registry 4474, January 1, 2015).

Effects of combined exercise training and electromyostimulation treatments in chronic heart failure: A prospective multicentre study

Background Exercise training as part of a comprehensive cardiac rehabilitation is recommended for patients with cardiac heart failure. It is a valuable method for the improvement of exercise tolerance. Some studies reported a similar improvement with quadricipital electrical myostimulation, but the effect of combined exercise training and electrical myostimulation in cardiac heart failure has not been yet evaluated in a large prospective multicentre study. Purpose The aim of this study was to determine whether the addition of low frequency electrical myostimulation to exercise training may improve exercise capacity and/or muscular strength in cardiac heart failure patients. Methods Ninety-one patients were included (mean age: 58 ± 9 years; New York Heart Association II/III: 52/48%, left ventricular ejection fraction: 30 ± 7%) in a prospective French study. The patients were randomised into two groups: 41 patients in exercise training and 50 in exercise training + electrical myostimulation. All patients underwent 20 exercise training sessions. In addition, in the exercise training + electrical myostimulation group, patients underwent 20 low frequency (10 Hz) quadricipital electrical myostimulation sessions. Each patient underwent a cardiopulmonary exercise test, a six-minute walk test, a muscular function evaluation and a quality of life questionnaire, before and at the end of the study. Results A significant improvement of exercise capacity (Δ peak oxygen uptake+15% in exercise training group and +14% in exercise training + electrical myostimulation group) and of quality of life was observed in both groups without statistically significant differences between the two groups. Mean creatine kinase level increased in the exercise training group whereas it remained stable in the combined group. Conclusions This prospective multicentre study shows that electrical myostimulation on top of exercise training does not demonstrate any significant additional improvement in exercise capacity in cardiac heart failure patients.

Effect of functional electrical stimulation on cardiovascular outcomes in patients with chronic heart failure

Background/design Functional electrical stimulation of lower limb muscles is an alternative method of training in patients with chronic heart failure (CHF). Although it improves exercise capacity in CHF, we performed a randomised, placebo-controlled study to investigate its effects on long-term clinical outcomes. Methods We randomly assigned 120 patients, aged 71 ± 8 years, with stable CHF (New York Heart Association (NYHA) class II/III (63%/37%), mean left ventricular ejection fraction 28 ± 5%), to either a 6-week functional electrical stimulation training programme or placebo. Patients were followed for up to 19 months for death and/or hospitalisation due to CHF decompensation. Results At baseline, there were no significant differences in demographic parameters, CHF severity and medications between groups. During a median follow-up of 383 days, 14 patients died (11 cardiac, three non-cardiac deaths), while 40 patients were hospitalised for CHF decompensation. Mortality did not differ between groups (log rank test P = 0.680), while the heart failure-related hospitalisation rate was significantly lower in the functional electrical stimulation group (hazard ratio (HR) 0.40, 95% confidence interval (CI) 0.21-0.78, P = 0.007). The latter difference remained significant after adjustment for prognostic factors: age, gender, baseline NYHA class and left ventricular ejection fraction (HR 0.22, 95% CI 0.10-0.46, P < 0.001). Compared to placebo, functional electrical stimulation training was associated with a lower occurrence of the composite endpoint (death or heart failure-related hospitalisation) after adjustment for the above-mentioned prognostic factors (HR 0.21, 95% CI 0.103-0.435, P < 0.001). However, that effect was mostly driven by the favourable change in hospitalisation rates. Conclusions In CHF patients, 6 weeks functional electrical stimulation training reduced the risk of heart failure-related hospitalisations, without affecting the mortality rate. The beneficial long-term effects of this alternative method of training require further investigation.

Effect of exercise training on endothelial function in heart failure patients: A systematic review meta-analysis

OBJECTIVE

Endothelial dysfunction contributes to the development and progression of cardiovascular disease and heart failure (HF) and is associated with an increased risk of mortality. Flow-mediated dilation (FMD) is widely utilised to assess endothelial function and is improved with exercise training in heart failure patients. The aim of this meta-analysis is to quantify the effect of exercise training in patients with heart failure.

BACKGROUND

A large number of studies now exist that have examined endothelial function in patients with heart failure. We sought to add to the current literature by quantifying the effect of exercise training on endothelial function.

METHODS

We conducted database searches (PubMed, EMBASE, PROQUEST and Cochrane Trials Register to June 2016) for exercise based rehabilitation trials in heart failure, using search terms exercise training, endothelial function, flow-mediated dilation (FMD) and endothelial progenitor cells (EPCs).

RESULTS

The 16 included studies provided a total of 529 participants, 293 in an intervention and 236 in controls groups. FMD was improved with exercise training in exercise vs. control, SMD of 1.08 (95%CI 0.70 to 1.46, p<0.00001).

CONCLUSION

Overall exercise training improved endothelial function, assessed via FMD, and endothelial progenitor cells in heart failure patients.

The mechanisms of breathlessness in heart failure as the basis of therapy

PURPOSE OF REVIEW

The review provides an overview of recent understanding in relation to the mechanisms relating to skeletal muscle and the sympathetic nervous system, and therapies for breathlessness which target these mechanisms. These are set in the context of established knowledge in this field.

RECENT FINDINGS

Despite strong evidence to support exercise training programmes, and recommendations in international guidelines, programmes are implemented poorly. Electrical stimulation appears to be a way of exercising people too frail to undertake a full exercise programme. There is evidence to support the use of opioids for breathlessness in other conditions, but as yet the evidence in chronic heart failure is mixed.

SUMMARY

Previous work in relation to the role of skeletal muscle and sympathetic nervous system has set the scene for targeted therapies for the relief of breathlessness in people with heart failure.

Muscle electrical stimulation improves neurovascular control and exercise tolerance in hospitalised advanced heart failure patients

BACKGROUND

We investigated the effects of muscle functional electrical stimulation on muscle sympathetic nerve activity and muscle blood flow, and, in addition, exercise tolerance in hospitalised patients for stabilisation of heart failure.

METHODS

Thirty patients hospitalised for treatment of decompensated heart failure, class IV New York Heart Association and ejection fraction ≤ 30% were consecutively randomly assigned into two groups: functional electrical stimulation (n = 15; 54 ± 2 years) and control (n = 15; 49 ± 2 years). Muscle sympathetic nerve activity was directly recorded via microneurography and blood flow by venous occlusion plethysmography. Heart rate and blood pressure were evaluated on a beat-to-beat basis (Finometer), exercise tolerance by 6-minute walk test, quadriceps muscle strength by a dynamometer and quality of life by Minnesota questionnaire. Functional electrical stimulation consisted of stimulating the lower limbs at 10 Hz frequency, 150 ms pulse width and 70 mA intensity for 60 minutes/day for 8-10 consecutive days. The control group underwent electrical stimulation at an intensity of < 20 mA.

RESULTS

Baseline characteristics were similar between groups, except age that was higher and C-reactive protein and forearm blood flow that were smaller in the functional electrical stimulation group. Functional electrical stimulation significantly decreased muscle sympathetic nerve activity and increased muscle blood flow and muscle strength. No changes were found in the control group. Walking distance and quality of life increased in both groups. However, these changes were greater in the functional electrical stimulation group.

CONCLUSION

Functional electrical stimulation improves muscle sympathetic nerve activity and vasoconstriction and increases exercise tolerance, muscle strength and quality of life in hospitalised heart failure patients. These findings suggest that functional electrical stimulation may be useful to hospitalised patients with decompensated chronic heart failure.