Background: Functional electrical stimulation (FES) improves exercise capacity and quality of life in chronic heart failure (CHF) patients. However, there is no evidence regarding the effectiveness of this treatment modality according to the severity of CHF. This study compares the effectiveness of FES on exercise capacity, endothelial function, neurohormonal status, and emotional stress in New York Heart Association (NYHA) III-IV versus NYHA II patients.
Methods and results: Eighteen NYHA II and 13 age- and sex-matched NYHA III-IV patients with stable CHF (left ventricular ejection fraction <35%) underwent a 6-week FES training program. Questionnaires addressing quality of life (Kansas City Cardiomyopathy Questionnaire, functional and overall), and emotional stress (Zung self-rating depression scale, Beck Depression Inventory), as well as plasma B-type natriuretic peptide (BNP), 6-minute walking distance test (6MWT), and endothelial function (flow-mediated dilatation [FMD]) were assessed at baseline and after completion of training protocol. 6MWT and plasma BNP improved significantly in 2 patient groups (both P < .001) after training program. The improvement of BNP was statistically greater in NYHA III-IV patients posttreatment than in those with NYHA II class (F=315.342, P < .001). Similarly, the improvement of 6MWT was statistically greater in NYHA III-IV group than in NYHA II patients (F=79.818, P < .001). Finally, an FES-induced greater improvement of FMD (F=9.517, P=.004) and emotional stress scores was observed in NYHA III-IV patients in comparison to NYHA II patients. There was a higher proportion of NYHA III-IV patients adhering to the FES training program for additional 3 months compared with the NYHA II group of patients (76.9% vs. 55.6%, P < .001).
Conclusion: FES might exert a greater beneficial effect on clinical and neurohormonal status of NYHA III-IV patients in comparison to NYHA II patients. This effect may have important clinical relevance leading to increased adherence of severe CHF patients to exercise rehabilitation programs.
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