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European Journal of Heart Failure 2008 10(7):709-713; doi:10.1016/j.ejheart.2008.05.014
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© 2008 European Society of Cardiology

Effects of functional electrical stimulation on quality of life and emotional stress in patients with chronic heart failure secondary to ischaemic or idiopathic dilated cardiomyopathy: A randomised, placebo-controlled trial

Apostolos Karavidasa, John Parissisb,*, Sophia Arapia, Dimitrios Farmakisb, Dimitrios Korresa, Maria Nikolaoub, John Fotiadisa, Nikolaos Potamitisa, Xenia Drivaa, Ioannis Paraskevaidisb, Evaggelos Matsakasa, Gerasimos Filippatosb and Dimitrios T. Kremastinosb

a Cardiology Department, General Hospital "G.Genimmatas" Athens, Greece
b Second Cardiology Department and Heart Failure Unit, University of Athens Medical School, Attikon University Hospital Athens, Greece

* Corresponding author. Aftokratoros Irakliou 17, 15122, Maroussi, Athens, Greece. Tel./fax: +30 210 5831295. E-mail address: jparissis{at}yahoo.com (J. Parissis).


   Abstract
Top
 Abstract
1. Introduction
 2. Methods
 3. Results
 4. Discussion
 References
 
Objective: Functional electrical stimulation (FES) improves exercise capacity and endothelial function in chronic heart failure (CHF) patients. This study evaluates the impact of FES on quality of life and emotional stress in patients with moderate to severe CHF.

Methods: Thirty patients with stable CHF (24 men; NYHA class II–III; left ventricular ejection fraction <35%) were randomly assigned (2:1) to a 6-week FES training program (n=20) or placebo (n=10). Questionnaires addressing quality of life [Kansas City Cardiomyopathy Questionnaire (KCCQ), functional and overall], and emotional stress [Zung self-rating depression scale (SDS), Beck Depression Inventory (BDI)], as well as plasma B-type natriuretic peptide (BNP) and 6-min walking distance test (6MWT) were assessed at baseline and after completion of training protocol.

Results: A significant improvement in KCCQ functional (F=76.666, p<0.001), KCCQ overall (F = 41.508, p<0.001), BDI (F = 17.768, p<0.001) and Zung SDS (F = 27.098, p<0.001) was observed in the FES group compared to placebo. Patients in the FES group had also a significant increase in 6MWT (F = 19.413, p<0.001) and a trend towards reduction in plasma BNP (F = 4.252, p=0.053) compared to placebo.

Conclusion: FES seems to have a beneficial effect on quality of life, exercise capacity and emotional stress in patients with moderate to severe CHF.

Key Words: Quality of life • Depression • Exercise training programs • Heart failure • B-type natriuretic peptide

Received November 16, 2007; Revised April 30, 2008; Accepted May 22, 2008


   1. Introduction
Top
 Abstract
 1. Introduction
2. Methods
 3. Results
 4. Discussion
 References
 
A number of studies have shown that exercise training can improve psychosocial outcomes in otherwise healthy individuals, increasing their self-esteem and decreasing depression. Exercise is beneficial as an antidepressant, inducing neurochemical and functional changes in the human brain that activate brain reward pathways [1]. Low levels of physical activity and low maximal oxygen uptake (VO2 max), on the other hand, have been associated with depression [2] and a Swedish study has shown that inactive elderly people have higher depression scores than more active individuals, both in terms of light and strenuous exercise [3].

Depression is a significant factor affecting the increasingly large population of chronic heart failure (CHF) patients. These patients are poor candidates for exercise due to their compromised health status and resulting limitations, such as diminished exercise capacity and possibly lack of motivation.

On the other hand, it is known that physical exercise confers significant beneficial effects in heart failure patients, in terms of endothelial function, skeletal and respiratory muscle performance and cardiac function. Functional electrical stimulation (FES) has been shown in a number of studies to be a useful and promising alternative to exercise training for the management of patients with CHF, since it has beneficial effects on exercise capacity, muscle performance, neurohormonal profile and endothelial function [4-5].

However, to our knowledge, no study has examined the impact of FES on the emotional status of CHF patients. Therefore, this study was conducted to determine the impact of FES, as an alternative exercise modality, on depressive symptoms and quality of life assessed by relevant questionnaires, in patients with CHF.


   2. Methods
Top
 Abstract
 1. Introduction
 2. Methods
3. Results
 4. Discussion
 References
 
2.1. Study population
Of 42 CHF patients screened for entry into the study, 30 (mean age 62.8±10.6 years, 24 males/6 females) agreed to participate. All patients were clinically stable on optimal medical therapy. Criteria for eligibility were; documented clinical signs and symptoms of heart failure, left ventricular ejection fraction less than 35% and New York Heart Association (NYHA) class II-III. The clinical characteristics of the patients are summarized in Table 1. The cause of heart failure was ischaemic (63%) or idiopathic dilated cardiomyopathy (37%).


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  		Table 1 Baseline demographic and clinical characteristics of the CHF patients according to treatment group

 
Exclusion criteria were: patients who had not reached the optimal dose of angiotensin converting enzyme inhibitors and/or beta-blockers, recent onset of decompensated CHF, acute coronary syndromes, chronic renal failure or dialysis, chronic inflammatory diseases or malignancies.

2.2. Protocol
The study protocol was approved by the Institute's Ethics Committee. All patients gave written informed consent. Patients were randomly assigned (2:1) to either the FES training or placebo, using a computer-generated randomisation schedule. The two groups differed in terms of electrical stimulation, which elicited strong contractions only in the FES group, whereas the placebo group received current input up to the sensory threshold without muscle contractions.

The patients underwent the training program in the physiotherapy department at our Institution, under the control of our chief therapist. Eight adhesive electrodes (size: 50x90 mm) were positioned on the skin over the upper lateral and lower medial aspects of the quadriceps muscle of both legs and over the upper and lower portions of the gastrocnemius muscles of both legs. On the quadriceps of both legs, the upper electrode was positioned 4 cm below the inguinal fold, while the lower electrode was placed above the kneecap. On the gastrocnemius, the upper electrode was positioned 2 cm below the popliteal fossa, while the lower was placed just above the Achilles tendon of both tibials. In the FES group, the stimulator was configured to deliver a direct electrical current at 25 Hz for 5 s followed by 5 s of rest. The intensity of the stimulation was adjusted to achieve a visible muscle contraction that was not sufficiently strong to cause discomfort or a significant movement at either the knee or the ankle joints. When the muscles of the right leg were contracted, the muscles of the left leg were relaxing and vice versa. The patients were trained for 30 min a day, 5 days per week for a total of 6 weeks. The placebo group was exposed to the same regimen as the FES group, using a lower intensity of stimulation (5 Hz) that did not lead to visible or palpable contractions, as judged objectively or subjectively [4].

Plasma B-type natriuretic peptide (BNP) levels were measured by standard immunoassay technique (Triage BNP assay, Biosite Inc., San Diego, California, USA) [6]. Six-minute walk distance (6MWT), as an index of exercise capacity, was assessed before and after completion of the training protocol. This test was performed in a properly graded (every 20 m) corridor of our heart failure clinic under the supervision of a physician who was blinded to the treatment status of each patient. Patients were also asked to complete instruments to screen for depressive symptoms and/or emotional stress (BDI and Zung SDS as two independently used tools) and to assess functional capacity and quality of life both at the baseline evaluation and after the training program. Neither of these tests differed significantly between the two groups at the baseline evaluation (Table 1).

2.3. Instruments

I). Beck Depression Inventory (BDI) is a self self-administered 21-item questionnaire that has been established for screening depressive symptoms in various populations. Since only five of its items concern somatic symptoms, while the remaining sixteen reflect non-somatic symptoms of depression, the BDI instrument has been extensively used in heart failure [7]. The standard cut-off point of ≥10 was used to classify patients as having depressive symptoms and emotional stress.
II). Zung self-rating depression scale (SDS) has been designed to provide a quantitative assessment of the subjective experience of depression. It contains 20 items covering affective, psychological and somatic features of emotional stress. Individuals without significant emotional stress typically score less than 40, while as score of 40 to 80 covers various grades of depressive symptomatology and serious emotional stress [8].
III).Kansas City Cardiomyopathy Questionnaire (KCCQ) is a disease specific, self-administered 23-item questionnaire that quantifies physical limitation and quality of life. It consists of different domains that can be summarized in a functional score (assessing physical activity and symptoms) and in a summary score (functional score and quality of life) which reflect the overall health status. Scale scoring is transformed to a 0 to 100 range, with lower levels implying worse function and life quality. KCCQ has proven to be valid and reliable and it appears very sensitive in monitoring clinical changes [9].

2.4. Statistical analysis
Statistical analysis was performed using the SPSS 11.0 statistical software package (SPSS Inc., Chicago, Illinois, USA). Continuous variables were expressed as mean±standard deviation. Categorical variables are expressed as percentages of the corresponding population. Continuous variables were tested for normal distribution by the Kolmogorov-Smirnov test and compared between groups at baseline using the Student's t test or the Mann-Whitney U test, accordingly. Two-way ANOVA for repeated measurements was used to assess the effects of treatment status on different variables in the two study groups; results were provided by the Sphericity test or the Greenhouse-Geisser test if the criteria for Sphericity were not met; base-10 logarithms were used for non-normally distributed variables. Pearson correlation was used to investigate the relationships between percent changes in values observed during treatment. A p<0.05 was considered statistically significant.


   3. Results
Top
 Abstract
 1. Introduction
 2. Methods
 3. Results
4. Discussion
 References
 
No significant differences were observed between the two study groups for any of the clinical, echocardiographic or biochemical variables tested at baseline (Table 1).

Compared with the placebo group, patients in the FES group had a significant increase in 6-min walk distance (F statistic=19.413, p<0.001) and a significant amelioration in all quality of life and depression scores, including KCCQ functional (F=76.666, p<0.001) and summary (F=41.508, p<0.001), Zung SDS (F=27.098, p<0.001) and BDI (F=17.768, p<0.001). Plasma BNP also showed a trend towards amelioration in the FES group (F=4.252, p=0.053). Table 2 summarizes the effects of the two treatment modalities on exercise capacity, neurohormonal activation, depressive symptoms and quality of life in the study population.


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  		Table 2 Exercise capacity, emotional status and quality of life measurements at baseline and after treatment in the two study groups

 
3.1. Correlations
FES-induced KCCQ functional increase significantly correlated with a concomitant decrease in Zung SDS (r=–0.57, p=0.001) and BDI (r=–0.422, p=025), as well as with an increase in 6MWT (r=0.435, p=.0.049). Zung SDS decrease in the patients of our study, also correlated significantly with a decrease in BDI (r=–0.631, p<0.001) and an increase in 6MWT (r=–0.438, p=0.047).


   4. Discussion
Top
 Abstract
 1. Introduction
 2. Methods
 3. Results
 4. Discussion
References
 
The present study demonstrates that functional electrical stimulation of the peripheral muscles improves functional capacity and neurohormonal activation in patients with stable CHF. Moreover, we showed for the first time that these beneficial effects are closely associated with the significant improvement in patients' quality of life and emotional stress. More specifically, we found that a 6 week-training program of FES increases the distance covered during the 6-minute walk test, with a respective reduction in BNP levels and an additional improvement in depression scales BDI and Zung, as well as in quality of life scales KCCQs.

FES-induced beneficial changes in peripheral haemodynamics and skeletal muscle metabolic status, reversion of a "deconditioning" process common in sedentary patients with heart failure and counteraction of the vicious cycle mobilized by activated neurohormonal and inflammatory pathways, are potential mechanisms that could explain the favourable outcomes in functional capacity and quality of life of patients with CHF.

Decreased exercise capacity, on the other hand, is a main factor restricting everyday life of CHF patients, thus compromising their quality of life [10]. The improved exercise capacity contributes to the general wellbeing of these patients in their daily activities, and this fact may beneficially affect their quality of life [11].

The FES-induced favourable effect on KCCQ scores, may also have prognostic implications in CHF patients, since these scales have been associated with adverse clinical outcomes and their improvement by therapeutic interventions may predict lower rehospitalisation rates [12].

On the other hand, plasma BNP levels have been proposed as an independent predictor for adverse outcomes in CHF [13], reflecting also the clinical severity of the disease. FES training seems to beneficially modulate the release of plasma BNP, possibly through the improvement of endothelial function and concomitant decrease of cardiac afterload that reduce end-systolic wall stress [4].

Moreover, FES improves depression symptoms in CHF patients providing an additional clinical advantage, since emotional stress has been shown to adversely affect both short- and long-term prognosis in CHF patients [14]. The prevalence of depression in hospitalised CHF patients ranges from 35 to 70% and depressive symptoms are associated with a significant increase in the risk of both mortality and readmission rate of these patients [15-17].

In this study, we assessed emotional stress using instruments that screen somatic and non-somatic depressive symptoms, which have been validated in the Greek language [17]. Thus, focusing for the first time on the impact of FES on the emotional status of CHF patients, we demonstrated that both Zung SDS and BDI scores were improved in patients undergoing a 6-week program of FES, but remained unchanged in the placebo group.

The FES-induced improvement in exercise capacity and functional status, the favourable effect on the patients' general wellbeing and their quality of life, as well as the alleviation of the numerous daily activity limitations experienced by these patients, are some of the probable reasons for the beneficial effect exerted on the patients' emotional status.

A number of studies have shown that running induces neurochemical and morphological adaptations in brain reward pathways, that account for its anti-depressive effect [1,18,19]. Functional electrical stimulation of peripheral muscles could constitute an alternative means of inducing these beneficial neurochemical and morphological effects in the brain, but further studies are needed in this area.

There are a number of limitations related to this study. First, the sample size (30 patients) was rather small. In addition, the patients were randomised in a 2:1 manner to FES or placebo, giving only 10 patients in the placebo group. Therefore, this trial should only be considered as a pilot study and the derived results as preliminary ones in need of further confirmation by larger patient populations. Finally, given the preliminary nature of the study, a power calculation was not included in the study design.

In conclusion, FES exerted a beneficial effect on both exercise capacity and quality of life in these CHF patients; in addition it favourably modulated their neurohormonal profile. Furthermore, the present study demonstrated that FES is related to lower depression scores in patients with chronic heart failure. These effects may have important clinical relevance, not only in terms of the daily life and emotional status of heart failure patients, but also for prognosis.


   References
Top
 Abstract
 1. Introduction
 2. Methods
 3. Results
 4. Discussion
 References
 

  1. Brene S., Bjornebekk A., Aberq E., Mathe A., Olson L., Werme M. Running is rewarding and anti-depressive. Physiol Behav (2007) 92:136–140.[CrossRef][Medline]
  2. Tolmunen T., Laukkanen J.A., Hintikka J., et al. Low maximal oxygen uptake is associated with elevated depressive symptoms in middle-aged men. Eur J Epidemiol (2006) 21:701–706.[CrossRef][Web of Science][Medline]
  3. Lindwall M., Rennemard M., Halling A., Berglund J., Hassmen P. Depression and exercise in elderly men and women: findings from the Swedish national study on aging and care. J Aging Phys Act (2007) 15:41–55.[Web of Science][Medline]
  4. Karavidas A., Raisakis G., Parissis J., et al. Functional electrical stimulation improves endothelial function and reduces peripheral immune responses in patients with chronic heart failure. Eur J Cardiovasc Prev Rehabil (2006) 13:592–597.[CrossRef][Web of Science][Medline]
  5. Deley G., Kervio G., Verges B., et al. Comparison of low-frequency electrical myostimulation and conventional aerobic exercise training in patients with chronic heart failure. Eur J Cardiovasc Prev Rehabil (2005) 12:226–233.[CrossRef][Web of Science][Medline]
  6. Maisel A.S., Krishnaswamy P., Nowak R.M., et al. Breathing Not Properly Multinational Study Investigators. Breathing Not Properly Multinational Study Investigators. Rapid measurement of B-type natriuretic peptide in the emergency diagnosis of heart failure. N Engl J Med (2002) 347:161–167.[Abstract/Free Full Text]
  7. Jiang W., Kuchibhatla M., Clary G.L., et al. Relationship between depressive symptoms and long-term mortality in patients with heart failure. Am Heart J (2007) 154:102–108.[CrossRef][Web of Science][Medline]
  8. Zung W.W.K., Richards C.B., Short M.J. Self-rating depression scale in an outpatient clinic. Arch Gen Psychiatry (1965) 13:508–515.[Abstract/Free Full Text]
  9. Green C.P., Porter C.B., Bresnahan D.R., Spertus J.A. Development and evaluation of the Kansas City Cardiomyopathy Questionnaire: a new health status measure for heart failure. J Am Coll Cardiol (2000) 35:1245–1255.[Abstract/Free Full Text]
  10. Maria Sarullo F., Gristina T., Brusca I., et al. Effect of physical training on exercise capacity, gas exchange and N-terminal pro-brain natriuretic peptide levels in patients with chronic heart failure. Eur J Cardiovasc Prev Rehabil (2006) 13:812–817.[CrossRef][Web of Science][Medline]
  11. Thompson D.R. Improving end-of-life care for patients with chronic heart failure. Heart (2007) 93:901–902.[Abstract/Free Full Text]
  12. Heidenreich P.A., Spertus J.A., Jones P.G., et al. Health status identifies heart failure outpatients at risk for hospitalization or death. J Am Coll Cardiol (2006) 47:752–756.[Abstract/Free Full Text]
  13. Emdin M., Passino C., Prontera C., et al. Cardiac natriuretic hormones, neuro-hormones, thyroid hormones and cytokines in normal subjects and patients with heart failure. Clin Chem Lab Med (2004) 42:627–636.[CrossRef][Web of Science][Medline]
  14. Joynt K.E., Whellan D.J., O'Connor C.M. Why is depression bad for the failing heart? A review of the mechanistic relationship between depression and heart failure. J Card Fail (2004) 10:258–270.[CrossRef][Web of Science][Medline]
  15. Havranek E.P., Ware M., Lowes B.D. Prevalence of depression in patients with congestive heart failure. Am J Cardiol (1999) 84:348–350.[CrossRef][Web of Science][Medline]
  16. Jiang W., Alexander J., Christopher E., et al. Relationship of depression to increased risk of mortality and re-hospitalization in patients with congestive heart failure. Arch Intern Med (2001) 161:1849–1856.[Abstract/Free Full Text]
  17. Parissis J.T., Nikolaou M., Farmakis V., et al. Clinical and prognostic implications of self-rating depression scales and plasma B-type natriuretic peptide in hospitalized patients with chronic heart failure. Heart (2008) 94(5):585–589.[Abstract/Free Full Text]
  18. Bjornebekk A., Mathe A.A., Brene S. Running has differential effects on NPY opiates and cell proliferation in an animal model of depression and controls. Neuropsychopharmacology (2006) 31:256–264.[CrossRef][Web of Science][Medline]
  19. Bjornebekk A., Mathe A.A., Brene S. The antidepressant effect of running is associated with increased hippocampus cell proliferation. Int J Neuropsychopharmacol (2005) 8:357–368.[CrossRef][Web of Science][Medline]

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