Functional electrical stimulation of lower limbs in patients with chronic heart failure

Physical training is an important component of therapy for patients with chronic heart failure (CHF) and is considered complementary to their pharmacological treatment. The majority of conventional rehabilitation programs include aerobic training, which has been demonstrated to induce significant beneficial effects on the neurohumoral, immunoreactive and functional status of patients with moderate CHF. Functional electrical stimulation (FES) of skeletal muscles constitutes an alternative training mode with beneficial effects comparable to classical aerobic exercise, suitable for patients with CHF who cannot participate in traditional training programs due to either advanced grades of CHF or the presence of comorbidities. We present a review of the numerous studies evaluating the effects of FES in CHF, focusing on its main effects on skeletal myopathy reversal, exercise tolerance improvement and quality of life modification.     

Low-frequency electrical stimulation increases muscle strength and improves blood supply in patients with chronic heart failure.

BACKGROUND: This study was designed to evaluate the effects of low-frequency electrical stimulation (LFES) on muscle strength and blood flow in patients with advanced chronic heart failure (CHF). METHODS AND RESULTS: Patients with CHF (n=15; age 56.5 +/- 5.2 years; New York Heart Association III - IV; ejection fraction 18.7 +/- 3.3%) were examined before and after 6 weeks of LFES (10 Hz) of the quadriceps and calf muscles of both legs (1 h/day, 7 days/week). Dynamometry was performed weekly to determine maximal muscle strength (F(max); N) and isokinetic peak torque (PT(max); Nm); blood flow velocity (BFV) was measured at baseline and after 6 weeks of LFES using pulsed-wave Doppler velocimetry of the right femoral artery. Six weeks of LFES significantly increased F(max) (from 224.5 +/- 96.8 N to 340.0 +/- 99.4 N; p<0.001), and also PT(max) (from 94.5 +/- 41.5 Nm to 135.3 +/- 28.8 Nm; p<0.01). BFV in the femoral artery increased after 6 weeks from 35.7 +/- 15.4 cm/s to 48.2 +/- 18.1 cm/s (p<0.05); BFV values at rest before and after 6 weeks of LFES did not differ significantly. CONCLUSIONS: LFES may improve muscle strength and blood supply, and could be recommended for the treatment of patients with severe CHF.     

Repeated sauna treatment improves vascular endothelial and cardiac function in patients with chronic heart failure

OBJECTIVES: The purpose of this study was to determine the mechanism by which 60 degrees C sauna treatment improves cardiac function in patients with chronic heart failure (CHF). BACKGROUND: We have previously reported that repeated 60 degrees C sauna treatment improves hemodynamic data and clinical symptoms in patients with CHF. We hypothesized that the sauna restores endothelial function and then improves cardiac function. METHODS: Twenty patients (62 plus minus 15 years) in New York Heart Association (NYHA) functional class II or III CHF were treated in a dry sauna at 60 degrees C for 15 min and then kept on bed rest with a blanket for 30 min, daily for two weeks. Ten patients with CHF, matched for age, gender and NYHA functional class, were placed on a bed in a temperature-controlled (24 degrees C) room for 45 min as the nontreated group. Using high-resolution ultrasound, we measured the diameter of the brachial artery at rest and during reactive hyperemia (percent flow-mediated dilation, %FMD: endothelium-dependent dilation), as well as after sublingual administration of nitroglycerin (%NTG: endothelium-independent dilation). Cardiac function was evaluated by measuring the concentrations of plasma brain natriuretic peptide (BNP). RESULTS: Clinical symptoms were improved in 17 of 20 patients after two weeks of sauna therapy. The %FMD after two-week sauna treatment significantly increased from the baseline value, whereas the %NTG-induced dilation did not. Concentrations of BNP after the two-week sauna treatment decreased significantly. In addition, there was a significant correlation between the change in %FMD and the percent improvement in BNP concentrations in the sauna-treated group. In contrast, none of the variables changed at the two-week interval in the nontreated group. CONCLUSIONS: Repeated sauna treatment improves vascular endothelial function, resulting in an improvement in cardiac function and clinical symptoms.     

Exercise training in patients with chronic heart failure improves endothelial function predominantly in the trained extremities.

The present study investigates whether lower-limb dominant exercise training in patients with chronic heart failure (CHF) improves endothelial function primarily in the trained lower extremities or equally in the upper and lower extremities. Twenty-eight patients with CHF were randomized to the exercise or control group. The exercise group underwent cycle ergometer training for 3 months while controls continued an inactive sedentary lifestyle. Exercise capacity (6-min walk test) and flow-mediated vasodilation in the brachial and posterior tibial arteries were evaluated. After 3 months, walking performance increased only in the exercise group (488+/-16 to 501+/-14 m [control]; 497+/-23 to 567+/-39 m [exercise, p<0.05]). The flow-mediated vasodilation in the brachial arteries did not change in either group (4.2+/-0.5 to 4.5+/-0.4% [control]; 4.3+/-0.5 to 4.6+/-0.4% [exercise]), but that in the posterior tibial arteries increased only in the exercise group (4.1+/-0.5 to 4.1+/-0.3% [control]; 3.6+/-0.3 to 6.4+/-0.6% [exercise, p<0.01]). Cycle ergometer training improved flow-mediated vasodilation in the trained lower limbs, but not in the untrained upper limbs. Exercise training appears to correct endothelial dysfunction predominantly by a local effect in the trained extremities.     

步行训练对老年慢性心力衰竭患者心脏功能康复的影响

目的:观察步行训练方式对老年慢性心力衰竭患者心功能康复的效果和安全性。方法:295例Ⅱ～Ⅲ级慢性心功能不全的老年患者随机被分为康复组(152例)和对照组(143例),康复组在药物治疗基础上进行步行训练,对照组只进行药物治疗。经过6个月的随访,对比两组治疗前、后的血压、静息心率、6min步行距离、心脏超声的左室射血分数(LVEF)和左室舒张末期内径(LVEDd)等的变化情况。结果:运动训练前不同组间一般情况、血压、静息心率、6min步行距离和左室功能无明显差异(P0.05);运动训练6个月后各组死亡情况没有差别;步行运动训练组总再次住院率(20.4%∶33.6%)和因心血管疾病再次住院率(11.8%∶22.8%)明显低于对照组(P均0.05);与运动训练前及对照组治疗后比较,康复组治疗后静息心率明显下降[(72.1±15.7)次/min,(74.3±16.8)次/min∶(66.8±12.4)次/min],6min步行距离[(284.9±104.7)m,(296.1±134.5)m∶(328.6±124.2)m]和LVEF[(33.4±9.7)%,(30.4±9.6)%∶(35.9±10.9)%]均明显增加(P均0.01);血压和LVEDd无明显变化(P0.05)。结论:一定强度的步行训练对老年慢性充血性心力衰竭患者心脏功能的康复是安全和有效的。     

Physical training reduces peripheral markers of inflammation in patients with chronic heart failure.

AIMS: Previous studies have shown an abnormal expression of cellular adhesion molecules and cytokines in chronic heart failure, which may be related to endothelial dysfunction characterizing this syndrome. Our study investigates the effects of physical training on serum activity of some peripheral inflammatory markers associated with endothelial dysfunction, such as granulocyte-macrophage colony-stimulating factor (GM-CSF), macrophage chemoattractant protein-1 (MCP-1), soluble intercellular adhesion molecule-1 (sICAM-1) and soluble vascular cell adhesion molecule-1 (sVCAM-1) in patients with chronic heart failure. METHODS AND RESULTS: Serum levels of GM-CSF, MCP-1, sICAM-1 and sVCAM-1 were determined in 12 patients with stable chronic heart failure (ischaemic heart failure: 6/12, dilated cardiomyopathy: 6/12, New York Heart Association: II-III, ejection fraction: 24+/-2%) before and after a 12-week programme of physical training in a randomized crossover design. In addition, the functional status of chronic heart failure patients was evaluated by using a cardiorespiratory exercise stress test to measure peak oxygen consumption. Physical training produced a significant reduction in serum GM-CSF (28+/-2 vs 21+/-2 pg. ml(-1), P<0.001), MCP-1 (192+/-5 vs 174+/-6 pg. ml(-1), P<0.001), sICAM-1 (367+/-31 vs 314+/-29 ng. ml(-1), P<0.01) and sVCAM-1 (1247+/-103 vs 1095+/-100 ng. ml(-1), P<0.01) as well as a significant increase in peak oxygen consumption (14.6+/-0.5 vs 16.5+/-0.5 ml. kg(-1)min(-1), P<0.005). A significant correlation was found between the training-induced improvement in peak oxygen consumption and percentage reduction in soluble adhesion molecules sICAM-1 (r=-0.72, P<0.01) and sVCAM-1 (r=-0.67, P<0.02). CONCLUSION: Physical training affects beneficially peripheral inflammatory markers reflecting monocyte/macrophage-endothelial cell interaction. Training-induced improvement in exercise tolerance is correlated with the attenuation of the inflammatory process, indicating that inflammation may contribute significantly to the impaired exercise capacity seen in chronic heart failure.     

Effective sleep apnoea treatment improves cardiac function in patients with chronic heart failure

Background

Sleep disordered breathing (SDB) is highly prevalent in patients with chronic heart failure (CHF) and is associated with adverse effects on cardiac geometry and function. Continuous positive airway pressure (CPAP) has been proved an effective treatment modality for obstructive sleep apnoea (OSA), whereas adaptive servoventilation (ASV) is more effective in patients with central sleep apnoea (CSA). The impact of selection of therapy and effective apnoea alleviation on cardiac performance and reverse left ventricular remodelling (r-LVR) has not yet been evaluated.

Methods

Eighty five patients with stable CHF were screened for SDB and underwent polysomnography and treatment according to the type of SDB. Clinical evaluation and a comprehensive echocardiographic study was performed before initiation of therapy and after six months of effective treatment (ventilator use > 5 h/day with AHI < 5 events/h).

Results

Seventeen compliant patients under effective treatment were included in the analysis (8 OSA under Autoset CPAP and 9 CSA under ASV). In both groups, a significant improvement in all measured, conventional and TDI LV systolic indexes was recorded, including LVEF (32% ± 6% vs. 27% ± 6%, p < 0.001). A decrease in LV end-systolic volume (189 ± 94 ml vs. 211 ± 88 ml, p = 0.015, difference > 10%) was indicative of r-LVR. Furthermore, RV systolic parameters were also increased (TAPSE, p < 0.001; systolic TDI wave from lateral tricuspid annular aspect, p = 0.001), whereas right heart dimensions and areas were diminished, indicating better pulmonary haemodynamics. Moreover, a significant improvement in patients' clinical status, as evaluated by New York Heart Association Class was also documented at the end of six months follow-up.

Conclusions

Effective alleviation of SDB in CHF patients is associated with significant improvements in LV and RV systolic function and r-LVR. Longitudinal studies are needed to evaluate effects on morbidity and mortality.     

运动康复改善老年慢性心衰患者心功能和生活质量的研究

目的:观察老年慢性心衰患者运动康复后心功能和生活质量的改变。方法:对60例老年慢性心衰病人在常规药物治疗的基础上,实施运动康复疗法,并与58例非康复组进行对照比较;观察出院时病人6min步行距离、运动耐量、平均住院日和心功能变化,同时测定血浆脑钠肽(BNP)含量,对其生活质量进行评定;观察随访一年时病人的心功能、再住院率和死亡率。结果:出院时康复组运动贮量、生活质量明显提高,NYHA心功能级别显著改善(P<0.05或<0.01),BNP水平和心室重量指数(LVMI)则显著降低(P<0.05);较之对照组除上述指标显著改善(P<0.05~<0.01)外,6min步行距离增加非常显著(P<0.01)平均住院日显著减少(P<0.05);随访一年时康复组病人的心功能、6min步行距离、运动贮量、生活质量、左室射血分数(LVEF)和E/A比值均明显增加,NYHA心功能级别显著改善(P<0.01),左房内径(LAd)、LVMI以及再入院率和死亡率明显低于对照组(P<0.01或P<0.05)。结论:运动康复可以改善心功能,提高运动耐量和生活质量,缩短住院时间,降低再入院率和死亡率;长期运动康复可能有改善心肌的重构的作用。     

运动康复改善老年慢性心衰患者心功能和生活质量的研究

目的:观察老年慢性心衰患者运动康复后心功能和生活质量的改变.方法:对60例老年慢性心衰病人在常规药物治疗的基础上,实施运动康复疗法,并与58例非康复组进行对照比较;观察出院时病人 6 min步行距离、运动耐量、平均住院日和心功能变化,同时测定血浆脑钠肽(BNP)含量,对其生活质量进行评定;观察随访一年时病人的心功能、再住院率和死亡率.结果:出院时康复组运动贮量、生活质量明显提高,NYHA心功能级别显著改善(P＜0.05或＜0.01),BNP水平和心室重量指数(LVMI)则显著降低(P＜0.05);较之对照组除上述指标显著改善(P＜0.05～＜0.01)外,6 min步行距离增加非常显著(P＜0.01)平均住院日显著减少(P＜0.05);随访一年时康复组病人的心功能、6 min步行距离、运动贮量、生活质量、左室射血分数(LVEF)和E/A比值均明显增加,NYHA心功能级别显著改善(P＜0.01),左房内径(LAd)、LVMI以及再入院率和死亡率明显低于对照组(P＜0.01或P＜0.05).结论:运动康复可以改善心功能,提高运动耐量和生活质量,缩短住院时间,降低再入院率和死亡率;长期运动康复可能有改善心肌的重构的作用.     

Adaptive servoventilation improves cardiac function in patients with chronic heart failure and Cheyne-Stokes respiration

BACKGROUND AND AIMS: Sleep disordered breathing (SDB), especially Cheyne-Stokes respiration (CSR) is common in patients with chronic heart failure (CHF). Adaptive servoventilation (ASV) was recently introduced to treat CSR in CHF. The aim of this study was to investigate the effects of ASV on CSR and CHF parameters. METHODS: In 29 male patients (63.9+/-9 years, NYHA> or =II, left ventricular ejection fraction [LV-EF]< or =40%), cardiorespiratory polygraphy, cardiopulmonary exercise (CPX) testing, and echocardiography were performed and concentrations of NT-proBNP determined before and after 5.8+/-3.5 months (median 5.7 months) of ASV (AutoSet CS2, ResMed) treatment. All patients also received guideline-driven CHF therapy. RESULTS: Apnoea-hypopnoea-index was reduced from 37.4+/-9.4/h to 3.9+/-4.1/h (p<0.001). Workload during CPX testing increased from 81+/-26 to 100+/-31 W (p=0.005), oxygen uptake (VO2) at the anaerobic threshold from 12.6+/-3 to 15.3+/-4 ml/kg/min (p=0.01) and predicted peak VO2 from 58+/-12% to 69+/-17% (p=0.007). LV-EF increased from 28.2+/-7% to 35.2+/-11% (p=0.001), and NT-proBNP levels decreased significantly (2285+/-2192 pg/ml to 1061+/-1293 pg/ml, p=0.01). CONCLUSIONS: In selected patients with CHF and CSR, addition of ASV to standard heart failure therapy is able to improve SDB, CPX test results, LV-EF and NT-proBNP concentrations.     

Therapy with cardiac contractility modulation electrical signals improves left ventricular function and remodeling in dogs with chronic heart failure.

OBJECTIVES: This study examined the effects of long-term delivery of cardiac contractility modulation (CCM) electric signals on left ventricular (LV) function and global, cellular, and molecular remodeling in dogs with chronic heart failure (HF). BACKGROUND: Acute studies in dogs with experimentally induced HF showed that CCM signals applied to the failing myocardium during the absolute refractory period improved LV function without increasing myocardial oxygen consumption. METHODS: In one study, dogs with intracoronary microembolization-induced HF were randomized to 3 months of active CCM monotherapy or to a sham-operated control group. In another study, 19 HF dogs were randomized to 3 months chronic monotherapy with extended release metoprolol succinate (MET-ER), MET-ER with CCM, or no therapy at all (control group). RESULTS: In CCM-only treated dogs, LV ejection fraction (EF) increased (27 +/- 1% vs. 33 +/- 1%, p < 0.0001) compared with a decrease in sham-operated control animals (27 +/- 1% vs. 23 +/- 1%, p < 0.001). The increase in EF seen with CCM-treated dogs was accompanied by reduced LV volumes, improved myocardial structure, reversal of the maladaptive fetal gene program, and an improvement in sarcoplasmic reticulum calcium cycling proteins. Dogs treated with a combination of MET-ER and CCM showed a greater increase in LV EF and a greater reversal of LV global, structural, and biochemical remodeling compared with dogs treated with MET-ER alone. CONCLUSIONS: In dogs with HF, long-term CCM therapy improves LV systolic function. The improvements are additive to those seen with beta-blockers. These findings are further strengthened by the concomitant benefits of CCM therapy on LV global, cellular, and biochemical remodeling.     

Exercise training improves function of circulating angiogenic cells in patients with chronic heart failure

Alterations in circulating angiogenic cells (CAC) and endothelial progenitor cells (EPC), known to contribute to endothelial repair, could explain the reversal of endothelial function in response to exercise training. Moreover, training-induced vascular remodeling might affect the acute response of EPC and CAC following a single exercise bout. We studied the impact of exercise training on CAC function and numbers of CD34⁺/KDR⁺ EPC in patients with chronic heart failure (CHF) and we assessed the effect of acute exercise on CAC and EPC in sedentary and trained patients. Twenty-one sedentary CHF patients underwent 6-month exercise training and were compared to a non-trained control group (n = 17) and 10 healthy age-matched subjects. At baseline and follow-up, flow-mediated dilation was assessed and graded exercise testing (GXT) was performed. Before and immediately after GXT, CAC migratory capacity was assessed in vitro and circulating CD34⁺/KDR⁺ EPC were quantified using flow cytometry. At baseline, CAC migration was significantly impaired in sedentary CHF patients but normalized acutely after GXT. Training corrected endothelial dysfunction, which coincided with a 77% increase in CAC migration (P = 0.0001). Moreover, the GXT-induced improvement detected at baseline was no longer observed after training. Numbers of CD34⁺/KDR⁺ EPC increased following 6-month exercise training (P = 0.021), but were not affected by GXT, either prior or post-training. In conclusion, the present findings demonstrate for the first time that exercise training in CHF reverses CAC dysfunction and increases numbers of CD34⁺/KDR⁺ EPC, which is accompanied by improvement of peripheral endothelial function. The acute exercise-induced changes in CAC function wane with exercise training, suggesting that repetitive exercise bouts progressively lead to functional endothelial repair.     

Long-term treatment with neutral endopeptidase inhibitor improves cardiac function and reduces natriuretic peptides in rats with chronic heart failure

OBJECTIVE: Increased secretion of atrial and brain natriuretic peptide (ANP and BNP) from hearts is known to exhibit favorable effects in patients and animals with heart failure, and inhibition of neutral endopeptidase (NEP), an enzyme that degrades ANP and BNP, may further increase these peptide levels. However, it is still unknown whether such elevation of the ANP and BNP may offer a therapeutic benefit to the progression of chronic heart failure (CHF). We examined the effects of ONO-9902, a novel NEP inhibitor, on changes in hemodynamic parameters, NEP activity and neurohumoral factors in rats with CHF induced by left coronary artery ligation (CAL). METHODS: Male Wistar rats (220-240 g) were subjected to induction of acute myocardial infarction by CAL. Rats were orally treated with ONO-9902 (300 mg/kg/day) from the 1st to 6th week after the operation. Hemodynamic and/or biochemical assessments were performed at the 1st and 6th weeks after the operation. RESULTS: A single administration of ONO-9902 inhibited the plasma and kidney NEP activities and thereby further augmented the elevation of plasma ANP concentration in rats with CAL at the 1st week after the operation. In rats with CAL at the 6th week after the operation, the left ventricular end-diastolic pressure (LVEDP) increased and cardiac output index (COI) decreased as compared with those of sham-operated rats. These changes were accompanied by marked increases in the plasma ANP, BNP and endothelin-1 (ET-1). Chronic treatment with ONO-9902 attenuated the increase in LVEDP and the decrease in COI. These changes were associated with a decrease in plasma ANP, BNP and ET-1 concentrations. CONCLUSIONS: The results suggest that chronic treatment with NEP inhibitor improves depressed cardiac function in rats with CHF. ONO-9902 may offer a new and possible therapeutic approach in patients with CHF.     

Levosimendan improves renal function in patients with advanced chronic heart failure awaiting cardiac transplantation

BackgroundLong-term impact of levosimendan on renal function remains undefined. Prospectively, we evaluated effects of levosimendan on renal function in patients with advanced chronic heart failure awaiting cardiac transplantation.Methods and ResultsOf 40 patients, 20 were randomized to receive levosimendan (10-minute bolus 12 μg/kg, followed by 0.1 μg/kg/min for 24 hours; LS Group), and 20 received no levosimendan (Controls). The groups did not differ in age, heart failure etiology, left ventricular ejection fraction, and plasma brain natriuretic peptide. Patients were followed for 3 months. At baseline, the groups did not differ in serum creatinine (1.92 ± 0.13 mg/dL in LS Group versus 1.91 ± 0.12 mg/dL in Controls, P = .81) and creatinine clearance (43.7 ± 2.9 mL/min versus 43.9 ± 2.8 mL/min, P = .84). At 3 months, we found a decrease in serum creatinine and an increase in creatinine clearance in LS Group, but not in Controls, leading to a significant intergroup difference in serum creatinine (1.60 ± 0.26 mg/dL in LS Group versus 1.90 ± 0.14 mg/dL in Controls, P = .005) and creatinine clearance (53.6 ± 8.6 mL/min versus 44.0 ± 3.3 mL/min, P = .005). An improvement in creatinine ≥0.5 mg/dL occurred in 50% patients from LS Group compared with 10% of Controls (P = .005).ConclusionsLevosimendan improves long-term renal function in advanced chronic heart failure patients awaiting cardiac transplantation.