Effect of chronic neuromuscular electrical stimulation on primary cardiopulmonary exercise test variables in heart failure patients: A systematic review and meta-analysis

Background: Cardiopulmonary exercise testing (CPX) is an important clinical assessment in patients with heart failure (HF). Neuromuscular electrical stimulation (NMES) has shown promise as an approach to improving cardiopulmonary performance during exercise and thus could improve key CPX measures. The primary aim of the proposed study is to perform a systematic review and meta-analysis on the effects of NMES on key CPX measures in HF patients. Methods: Data sources: A systematic search without date or language restriction was conducted using Medline, Embase.com, Cochrane Central Register of Controlled Trials and CINAHL, Amedeo and PEDro. Study eligibility criteria: Randomized controlled trials, with or without crossover strategy, of NMES-based interventions and a comparison group submitted to usual medical care or exercise. Participants and interventions: Systolic HF patients; NMES-based interventions using skin electrodes to produce a muscle contraction. Study appraisal and synthesis methods: Studies were independently rated for quality (The Jadad Scale, PEDro Scale and The Quality of Research Score Sheet). Net changes were compared by weighted mean difference and 95% confidence interval. Heterogeneity among included studies was explored qualitatively and quantitatively. Begg's funnel plots and the Egger's regression assessed publication bias. Results: Findings suggest that NMES provides similar gains in CPX performance compared to traditional exercise or usual treatment. Conclusions: CPX performance has substantial prognostic and functional importance in the HF population. Our results suggest that NMES improves CPX performance and thus may be a valuable therapeutic intervention, positively altering the clinical trajectory of patients with HF.