Rev Bras Fisiol Exerc. 2026;25(1):e255658

doi: 0.33233/rbfex.v25i1.5658

REVIEW

Neuromuscular electrostimulation in patients with heart failure: a systematic review with meta-analysis

Eletroestimulação neuromuscular em pacientes com insuficiência cardíaca: uma revisão sistemática com metanálise

 

Aline de Sousa Nassif, Fernanda Lobo de Jesus Brito, Gilmara Santa Rosa Santos, André Luiz Lisboa Cordeiro

 

Centro Universitário Nobre, Feira de Santana, BA, Brazil

 

Received: February 16, 2026; Accepted: May 27, 2026

Correspondence: André Luiz Lisboa Cordeiro, andrelisboacordeiro@gmail.com

 

How to cite

AS Nassif, FLJ Brito, GSR Santos, ALL Cordeiro. Neuromuscular electrostimulation in patients with heart failure: a systematic review with meta-analysis. Rev Bras Fisiol Exerc. 2026;25(1):e255658. doi: 10.33233/rbfex.v25i1.5658

 

Abstract

Introduction: Chronic Heart Failure (CHF) occurs when the heart is unable to meet the body's demands adequately, resulting in reduced blood flow. The patient experiences dyspnea, fatigue, and an inability to perform exercises that require greater effort. Neuromuscular electrostimulation (NMES) has been used as a treatment to increase muscle strength, functional capacity, and quality of life. Objective: To review the effectiveness of NMES on muscle strength, quality of life, and functional capacity in patients with heart failure. Methods: This is a systematic review using the PICO strategy, with searches conducted in the PUBMED, SciELO, and LILACS databases using the descriptors: heart failure, transcutaneous electrical nerve stimulation, quality of life, muscle strength, and functional status, combined with the boolean operators 'AND' and 'OR'. Results: Eighteen studies were included after selection. NMES showed no statistically significant difference on the functional capacity outcome (difference between means 12.06 meters; 95% CI, -2.55 to +26.66), but there was a statistically significant difference in quality of life (difference between means 4.20 points; 95% CI, 2.79 to 5.62). The studies showed superiority in muscle strength for patients with CHF who were exposed to NMES. Conclusion: Neuromuscular electrostimulation can safely be implemented in patients with heart failure, positively impacting quality of life and muscle strength, but without affecting functional capacity.

Keywords: heart failure; transcutaneous electrical nerve stimulation; quality of life; muscle strength; functional status

 

Resumo

Introdução: A insuficiência cardíaca crônica (ICC) ocorre quando o coração se torna incapaz de atender adequadamente às demandas do organismo, levando à redução do fluxo sanguíneo. O paciente apresenta dispneia, fadiga e incapacidade de realizar exercícios que exigem maior esforço. A eletroestimulação neuromuscular (EENM) tem sido utilizada como tratamento para aumentar a força muscular, a capacidade funcional e a qualidade de vida. Objetivo: Revisar a efetividade da eletroestimulação neuromuscular sobre força muscular, qualidade de vida e capacidade funcional em pacientes com insuficiência cardíaca. Métodos: Trata-se de uma revisão sistemática utilizando a estratégia PICO, com buscas realizadas nas bases de dados PUBMED, SciELO e LILACS, utilizando os descritores: insuficiência cardíaca, estimulação elétrica nervosa transcutânea, qualidade de vida, força muscular e estado funcional, combinados pelos operadores booleanos “AND” e “OR”. Resultados: Dezoito estudos foram incluídos após o processo de seleção. A EENM não demonstrou diferença estatisticamente significativa no desfecho capacidade funcional (diferença entre médias de 12,06 metros; IC 95%, -2,55 a +26,66), porém houve diferença estatisticamente significativa para qualidade de vida (diferença entre médias de 4,20 pontos; IC 95%, 2,79 a 5,62). Os estudos demonstraram superioridade na força muscular em pacientes com ICC submetidos à EENM. Conclusão: A eletroestimulação neuromuscular pode ser implementada com segurança em pacientes com insuficiência cardíaca, impactando positivamente a qualidade de vida e a força muscular, porém sem efeito sobre a capacidade funcional.

Palavras-chave: insuficiência cardíaca; estimulação elétrica nervosa transcutânea; qualidade de vida; força muscular; estado funcional

 

Introduction

 

Heart failure (HF) is a clinical condition characterized by the heart's inability to pump blood efficiently, leading to symptoms such as fatigue, dyspnea, and fluid retention. According to McMurray et al. [1], the prevalence of HF has been increasing globally due to the aging population and the longer survival of patients with cardiovascular diseases. Despite therapeutic advances, HF still presents a high rate of morbidity and mortality, making it necessary to explore alternatives to improve patients' quality of life. Cardiovascular rehabilitation has become an important approach, and neuromuscular electrostimulation (NMES) emerges as a promising intervention to optimize the muscular and functional performance of patients with HF [2].

NMES uses electrical stimuli to promote muscle contraction and improve muscle strength and endurance in individuals with neuromuscular dysfunctions. In patients with HF, peripheral muscle function is often compromised due to the chronic deconditioning process, leading to reduced functional capacity [3]. According to Barlow et al. [4], NMES has shown potential in the rehabilitation of skeletal muscles, particularly in the lower limbs, which are more affected by HF. This treatment modality is capable of stimulating both slow and fast-twitch muscle fibers, improving muscle trophism and reducing the risk of atrophy [5].

Recent studies have shown that NMES can improve muscle strength, exercise tolerance, and quality of life in patients with heart failure [6,7]. The combination of NMES with cardiovascular rehabilitation programs has proven effective in optimizing outcomes in terms of functionality and overall physical health of patients [7]. However, there are discrepancies regarding the most appropriate stimulation protocol, such as frequency, intensity, and duration of the treatment. Among these parameters, the personalization of the therapy appears to be a key factor in maximizing the benefits [8].

Based on current evidence, it is expected that this will provide support for the integration of NMES into clinical cardiovascular rehabilitation practice, offering more effective therapeutic alternatives for this patient population [9,10]. In light of this scenario, the present systematic review aims to assess the effectiveness of NMES on muscle strength, quality of life, and functional capacity in patients with heart failure.

 

Methods

 

Study type and registration

 

This systematic review was completed following the guidelines of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) [11]. The article was registered in the International Prospective Register of Systematic Reviews (PROSPERO) with the number CRD42025637595.

 

Eligibility criteria

 

This systematic review used the PICOS strategy [12]. The study population consisted of heart failure patients who underwent neuromuscular electrostimulation. The control group consisted of patients who did not undergo electrostimulation. The outcomes were related to muscle strength, quality of life, and functional capacity. We included randomized clinical trials, with no restrictions on language or year of publication.

 

Information sources

 

A search was conducted on the computer, consulting Web of Science, Latin American and Caribbean Literature in Health Sciences (LILACS), PubMed, Cochrane Central Register of Controlled Trials (CENTRAL), and OVID. Additionally, the reference lists of previous systematic reviews and eligible clinical trials for this review were examined. The search for articles was completed in November 2024.

 

Search

 

The search was based on the previously described PICOS strategy and the boolean operators AND and OR. The search strategy used in PubMed is presented in Chart 1.

 

Chart 1 – Search strategy

 

Study selection

 

This systematic review included randomized clinical trials involving patients with heart failure. To be eligible, the clinical trial had to assign heart failure patients to a neuromuscular electrostimulation treatment. Studies, regardless of sex, were also included. Neuromuscular electrostimulation (NMES) consists of applying an electrical current, which can be either low or medium frequency, through electrodes placed on the skin to stimulate a specific muscle. Studies involving other types of interventions combined with NMES were excluded.

 

Data collection process

 

For the extraction of selected articles, the following steps were followed: title screening (first step), abstract review (second step), and full-text reading (third step). Then, an exploratory reading of the selected studies was performed, followed by a selective and analytical reading. The data extracted from the articles were summarized by authors, journal, year, title, and conclusions, to gather important information for the research.

The methodological quality of the studies was assessed by three independent reviewers. When disagreements arose, the article was read in full for reassessment. If the disagreement persisted, a fourth reviewer evaluated the study and made the final decision.

 

Data items

 

Two authors independently extracted data from the published reports using a standard data extraction method, considering the following aspects:

 

  1. Study population characteristics, such as mean age, sex, number of patients, and diagnosis;

  2. Intervention details, including sample size, type of neuromuscular electrical stimulation, presence of supervision, intensity, frequency, and duration of each session;

  3. Follow-up;

  4. Loss to follow-up;

  5. Outcome measures;

  6. Reported results.

 

Quality of each study

 

The methodological quality was assessed using the PEDro scale [13], which includes 11 items: 1-Eligibility criteria; 2-Random allocation; 3-Concealed allocation; 4-Baseline comparison; 5-Blinding of participants; 6-Blinding of therapists; 7-Blinding of assessors; 8-Adequate follow-up; 9-Intention-to-treat analysis; 10-Comparisons between groups; 11-Point estimates and variability. Each item is scored as present (1) or absent (0), resulting in a maximum score of 10 points, excluding the first item.

 

Synthesis of results

 

The presence of heterogeneity was evaluated using the chi2 test and the I2 statistic. This statistic illustrates the percentage of variability in effect estimates from heterogeneity rather than sampling error.

 

Statistical assessment

 

The mean difference between groups and the respective 95% confidence intervals were calculated and used to quantify the effect of continuous outcomes. For the meta-analyzes in which the studies used the same scales, the results were presented as mean difference (MD) and 95% confidence intervals. Otherwise, the effects were calculated using standardized mean difference (SMD) and 95% confidence intervals. The effect size of the interventions was defined as small (MD < 10% of the scale or SMD < 0.4); moderate (MD = 10% to 20% of the scale or SMD = 0.41 to 0.7) or large (MD > 20% of the scale or SMD > 0.7).

 

Results

 

Study selection and characteristics

 

According to the data presented in the article selection flowchart (Figure 1), the database search yielded a total of 1,980 articles, with 43 duplicates. Initially, 1,870 articles were excluded based on title and abstract screening. After full-text review, 49 articles were excluded because they combined NMES with other interventions. Therefore, this systematic review included 18 articles, which met the eligibility criteria for inclusion in this review.

 

 

Figure 1 - Flowchart for study selection

 

Methodological quality results

 

According to the PEDro scale, six studies were rated as having low methodological quality, eleven as moderate, and two as high. The criteria evaluated by the PEDro scale, and the scores obtained by each study are presented in detail in Table I.

 

Table I - Classification of articles on the PEDro Scale

 

 Participants

 

A total of 292 patients received the intervention in the studies included in this review. The age ranged from 18 to 66 years and the prevalence was male with 195 (66%). The remaining data are in Table II.

Table III shows the main parameters used to apply NMES to the study population.

 

Table II - Summary of the characteristics of the articles analyzed

 

Table III - Characteristics of the NMES intervention in the studies included in the review

 

Functional capacity

 

Sixteen studies [14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,31] analyzed the impact of EENM on functional capacity. For the meta-analysis of this comparison, a random model was used (I2 = 74%, df = 15, p = 0.00001), which revealed no statistically significant difference between the groups in the comparison between the EENM and the control (difference between the means 12.06 meters; 95% CI, -2.55 to +26.66; Fig. 2). 

 

 

Figure 2 - Forest plot of the results of the meta-analysis 

 

Quality of life

 

Nine studies [14,18,19,22,24,26,27,28,31] analyzed the impact of EENM on quality of life. For the meta-analysis of this comparison, a random model was used (I2 = 97%, df = 8, p = 0.00001), in which there was a statistically significant difference between the groups in the comparison between the EENM and the control (difference between the means 4.20 points; 95% CI, 2.79 to 5.62; Fig. 3). 

 

 

Figure 3 - Forest plot of the results of the meta-analysis 

 

We also conducted a specific analysis, separating the effect on functional capacity during hospitalization and in phase 2 (Figures 4 and 5).

 

Functional capacity in hospital

 

Three studies analyzed the impact of EENM on functional capacity in hospital scenarios. For the meta-analysis of this comparison, a fixed model was used (I2 = 94%, df = 2, p < 0.00001), in which there was no statistically significant difference between the groups in the comparison between the EENM and the control (difference between the means 7.02 meters; 95% CI, -6.25 to +20.30; Fig. 4). 

 

 

Figure 4 - Forest plot of the results of the meta-analysis 

 

Functional capacity in out-of-hospital scenario

 

Thirteen studies analyzed the impact of EENM on functional capacity in out-of-hospital scenarios. For the meta-analysis of this comparison, a fixed model was used (I2 = 53%, df = 12, p = 0.01), in which there was no statistically significant difference between the groups in the comparison between the EENM and the control (difference between the means 2.12 meters; 95% CI, -3.20 to +7.45; Fig. 5). 

 

 

Figure 5 - Forest plot of the results of the meta-analysis 

 

Discussion

 

Neuromuscular Electrical Stimulation (NMES) has been widely investigated as a therapeutic tool to improve functional capacity, muscle strength, and quality of life in patients with chronic heart failure (CHF). The present discussion analyzes the results of several studies that evaluated the impact of NMES in patients with stable or decompensated CHF, addressing both the effectiveness of this approach and the variables that may influence the outcomes.

The results of the reviewed studies consistently demonstrate that the distance covered in the 6-minute walk test (6MWT) is a variable sensitive to changes induced by NMES. Most studies reported significant improvements in patients' functional capacity, with notable works by Deley et al. [15] and Eicher et al. [17], which showed substantial increases in the distance covered with the use of NMES. For example, Deley et al. [15] observed a 13.8% increase in the NMES group compared to a 16.5% increase in the conventional exercise control group. The effectiveness of NMES was even more pronounced in studies such as Sacilotto et al. [27], which demonstrated an average increase of 120 meters in the distance covered by patients following NMES treatment.

This improvement can be explained by the ability of NMES to directly activate muscles without requiring voluntary effort. For patients with significant muscle weakness, which is common in the advanced stages of CHF, electrical stimulation allows for the activation of peripheral and respiratory muscles that are not sufficiently recruited during conventional physical activities, such as walking. Additionally, NMES can enhance muscle efficiency, promoting strength gains and reducing fatigue. This mechanism makes it particularly beneficial for individuals who struggle with muscle activation due to the limitations imposed by their condition.

Although both NMES and conventional exercise have shown beneficial effects on functional capacity, the impact of NMES tends to be more pronounced in patients with limited mobility or severe physical restrictions. In studies such as those by Groehs et al. [26] and Deley et al. [18], NMES produced greater increases in the distance covered in the 6MWT compared to conventional interventions, especially in patients with advanced CHF or marked muscle weakness. This suggests that NMES can provide a more effective means of improving functional capacity in individuals who are less able to perform traditional exercises due to their physical limitations. By directly stimulating the muscles, NMES helps overcome some of the barriers posed by the disease, leading to more substantial gains in mobility.

Although studies demonstrate benefits in preserving muscle mass and strength, as well as in improving cardiorespiratory function, gaps remain in the understanding of the underlying cellular and molecular processes. Investigating aspects such as selective muscle fiber recruitment, modulation of peripheral perfusion, influence on tissue oxygenation, and effects on metabolic and inflammatory pathways may provide stronger support for evidence-based practice. This mechanistic understanding would allow for the development of more targeted protocols, the identification of patient subgroups that may benefit more significantly, and the safe and effective translation of scientific evidence into clinical practice.

On the other hand, in patients with preserved mobility or better functional capacity, conventional training with aerobic and resistance exercises, as used in Dobšák et al. [14], demonstrated similar or even superior effects compared to NMES. The active mobilization provided by conventional exercise may be more effective in maintaining and improving aerobic capacity and muscle strength in patients with less physical impairment. Therefore, while NMES may be advantageous for patients in more advanced stages of the disease or with severely limited mobility, conventional exercise remains a relevant strategy for patients with less severe CHF. In essence, the choice between NMES and conventional exercise largely depends on the patient's stage of the disease and physical limitations. For those with more preserved function, conventional exercise can provide more comprehensive benefits, whereas NMES serves as an effective tool for patients with significant functional decline.

The variability in the results observed across different studies can be attributed to several factors, with a key focus on the intensity and frequency of the NMES protocols used. Studies with higher stimulation frequencies, such as 50 Hz (observed in Groehs et al. [26] and Sacilotto et al. [27]), showed better results in terms of muscle strength increase and distance covered in the 6MWT. This is because intense stimulation tends to generate visible and stronger muscle contractions, which are more effective in improving muscle capacity. In contrast, low-frequency protocols and suboptimal intensity may have limited effects, as observed in studies by Nuhr et al. [24] and Ennis et al. [31], where improvements were less pronounced or even not significant. The intensity of the muscular work performed with NMES is a determining factor in the effectiveness of the intervention, as a lower intensity may not be sufficient to promote significant physiological adaptations. The proper balance between frequency, intensity, and duration of stimulation is essential for achieving the desired therapeutic outcomes. Therefore, tailoring the protocol to the individual patient's condition and needs is crucial to maximizing the benefits of NMES.

Moreover, the heterogeneity of NMES protocols used across the reviewed trials — including differences in stimulation frequency, duration, intensity, and treatment length — makes it challenging to establish standardized recommendations and may partly explain the divergent results reported in literature.

Another factor that can influence the results is the duration of the treatment protocol. Longer protocols, such as those used in Karavidas et al. [22] and Banerjee et al. [21], generally produce more robust results. The continuity of stimulation over weeks or months appears to be crucial for promoting sustained muscle adaptations and long-term benefits. Shorter protocols may have immediate beneficial effects, but they often fail to sustain improvements in functional capacity and quality of life over time. This suggests that for NMES to be truly effective, especially in improving the long-term health and well-being of patients with chronic heart failure, consistent and prolonged use of the therapy is needed. Short-term gains may be encouraging, but without continued stimulation, patients may experience a return to baseline levels of function. Hence, protocols with longer duration are likely to have a more lasting impact on both muscle strength and overall functional capacity.

Improvement in quality of life is another important point observed in the studies. Although NMES has led to improvements in functional capacity, its effects on quality of life have been more variable. Some studies, such as those by Groehs et al. [26] and Sacilotto et al. [27], showed significant improvements in quality of life, with reductions in symptoms of dyspnea and fatigue. These benefits may be attributed to the reduction in muscular overload and the improvement in exercise efficiency, which, in turn, can alleviate the symptoms associated with heart failure. However, studies such as those by Harris et al. [18] and Ennis et al. [30] found no significant differences between the NMES and control groups in quality of life, suggesting that, despite the benefits to functional capacity, NMES may not be sufficient to induce significant changes in psychological or emotional aspects, which could require a more holistic therapeutic approach.

Although the results of the reviewed studies are promising, several limitations must be considered. Many of the studies have small sample sizes and a heterogeneity in stimulation protocols, which makes direct comparisons between the results difficult [30,31]. Additionally, most of the studies include patients in more advanced stages of heart failure, which may limit the generalization of the findings to populations with less severe heart failure. Future investigations should consider more heterogeneous samples, including different stages of heart failure, to assess the effects of NMES on various populations. Moreover, further studies are needed to determine the ideal doses of intensity and duration for the NMES protocol, as well as the composition of rehabilitation programs, which could combine conventional exercises with NMES.

 

Conclusion

 

The results of this review indicate that NMES may provide benefits in quality of life and, in some studies, improvements in functional capacity such as the 6-minute walk test. However, when statistically pooled, the impact on functional capacity was not consistent across trials, highlighting the divergence between narrative interpretation and statistical conclusions. NMES appears to be particularly useful for patients with limited mobility or significant muscle weakness, offering advantages that conventional exercise may not always provide. Nevertheless, NMES protocols should be carefully adjusted in terms of frequency and intensity to maximize their potential benefits. For patients with preserved mobility, conventional training remains a valid and effective strategy, and its combination with NMES may enhance outcomes. Ultimately, a multimodal therapeutic approach — including NMES, structured exercise and continuous monitoring of quality of life — may represent the most appropriate strategy for managing patients with chronic heart failure.

 

Conflict of interest

The authors declare no conflict of interest.

 

Sources of funding

This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.

 

Authors' contributions

Conception and design of the research: Nassif AS, Brito FLJ, Santos GSR, Cordeiro ALL; Data collection: Nassif AS, Brito FLJ, Santos GSR; Data analysis and interpretation: Cordeiro ALL; Manuscript writing: Nassif AS, Brito FLJ, Santos GSR; Critical revision of the manuscript for important intellectual content: Cordeiro ALL

 

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