Pedro Dal Lago

Inspiratory muscle training in patients with heart failure: meta-analysis of randomized trials

Patients with chronic heart failure (CHF) may have lower inspiratory muscle strength and endurance, which may contribute to exercise intolerance. Inspiratory muscle training (IMT) can have beneficial effects on these patients. Thus, the aim of this study was to systematically review the effects of IMT compared to control groups (placebo-IMT or another intervention) in patients with CHF. A search of databases (MEDLINE, Cochrane CENTRAL and PEDro) and references of published studies, from 1960 to 2011, was conducted. Randomized trials comparing IMT to control groups in the treatment of patients with CHF were included. The GRADE approach was used to determine the quality of evidence for each outcome. Of 119 articles identified, 7 studies were included. IMT increased the distance walked in the six-minute walk test [69 m (95% CI: 7.21 to 130.79)] (very low evidence) and maximal static inspiratory pressure [23.36 cmH20 (95% CI: 11.71 to 35.02)] (low evidence) compared to control groups. However, IMT provides a significant improvement in peak oxygen consumption only in the studies that performed IMT for 12 weeks against no inspiratory load in patients with inspiratory muscle weakness [3.02 ml/kg/min-1 (95% CI: 0.43 to 5.61)]. IMT improves functional capacity and inspiratory muscle strength thereby deserving consideration as an additional intervention in patients with CHF. Larger and better-designed studies, however, are needed to clarify the potential benefit of IMT in this patient population.

Respiratory muscle training improves hemodynamics, autonomic function, baroreceptor sensitivity, and respiratory mechanics in rats with heart failure

Respiratory muscle training (RMT) improves functional capacity in chronic heart-failure (HF) patients, but the basis for this improvement remains unclear. We evaluate the effects of RMT on the hemodynamic and autonomic function, arterial baroreflex sensitivity (BRS), and respiratory mechanics in rats with HF. Rats were assigned to one of four groups: sedentary sham (n = 8), trained sham (n = 8), sedentary HF (n = 8), or trained HF (n = 8). Trained animals underwent a RMT protocol (30 min/day, 5 day/wk, 6 wk of breathing through a resistor), whereas sedentary animals did not. In HF rats, RMT had significant effects on several parameters. It reduced left ventricular (LV) end-diastolic pressure (P < 0.01), increased LV systolic pressure (P < 0.01), and reduced right ventricular hypertrophy (P < 0.01) and pulmonary (P < 0.001) and hepatic (P < 0.001) congestion. It also decreased resting heart rate (HR; P < 0.05), indicating a decrease in the sympathetic and an increase in the vagal modulation of HR. There was also an increase in baroreflex gain (P < 0.05). The respiratory system resistance was reduced (P < 0.001), which was associated with the reduction in tissue resistance after RMT (P < 0.01). The respiratory system and tissue elastance (Est) were also reduced by RMT (P < 0.01 and P < 0.05, respectively). Additionally, the quasistatic Est was reduced after RMT (P < 0.01). These findings show that a 6-wk RMT protocol in HF rats promotes an improvement in hemodynamic function, sympathetic and vagal heart modulation, arterial BRS, and respiratory mechanics, all of which are benefits associated with improvements in cardiopulmonary interaction.

Inspiratory muscle training reduces sympathetic nervous activity and improves inspiratory muscle weakness and quality of life in patients with chronic heart failure: a clinical trial.

PURPOSE: To evaluate the effect of inspiratory muscle training (IMT) on cardiac autonomic modulation and on peripheral nerve sympathetic activity in patients with chronic heart failure (CHF). METHODS: Functional capacity, low-frequency (LF) and high-frequency (HF) components of heart rate variability, muscle sympathetic nerve activity inferred by microneurography, and quality of life were determined in 27 patients with CHF who had been sequentially allocated to 1 of 2 groups: (1) control group (with no intervention) and (2) IMT group. Inspiratory muscle training consisted of respiratory exercises, with inspiratory threshold loading of seven 30-minute sessions per week for a period of 12 weeks, with a monthly increase of 30% in maximal inspiratory pressure (PImax) at rest. Multivariate analysis was applied to detect differences between baseline and followup period. RESULTS: Inspiratory muscle training significantly increased PImax (59.2 ± 4.9 vs 87.5 ± 6.5 cmH2O, P = .001) and peak oxygen uptake (14.4 ± 0.7 vs 18.9 ± 0.8 mL·kg−1·min−1, P = .002); decreased the peak ventilation ( E)/carbon dioxide production (VCO2) ratio (35.8 ± 0.8 vs 32.5 ± 0.4, P = .001) and the E/ CO2 slope (37.3 ± 1.1 vs 31.3 ± 1.1, P = .004); increased the HF component (49.3 ± 4.1 vs 58.4 ± 4.2 normalized units, P = .004) and decreased the LF component (50.7 ± 4.1 vs 41.6 ± 4.2 normalized units, P = .001) of heart rate variability; decreased muscle sympathetic nerve activity (37.1 ± 3 vs 29.5 ± 2.3 bursts per minute, P = .001); and improved quality of life. No significant changes were observed in the control group. CONCLUSION: Home-based IMT represents an important strategy to improve cardiac and peripheral autonomic controls, functional capacity, and quality of life in patients with CHF.

Aerobic exercise improves the inflammatory profile correlated with cardiac remodeling and function in chronic heart failure rats

OBJECTIVE: The aim of the present study was to evaluate the effect of 8 weeks of aerobic exercise training on cardiac functioning and remodeling and on the plasma levels of inflammatory cytokines in chronic heart failure rats. METHODS: Wistar rats were subjected to myocardial infarction or sham surgery and assigned to 4 groups: chronic heart failure trained (n = 7), chronic heart failure sedentary (n = 6), sham trained (n = 8) and sham sedentary (n = 8). Four weeks after the surgical procedures, the rats were subjected to aerobic training in the form of treadmill running (50 min/day, 5 times per week, 16 m/min). At the end of 8 weeks, the rats were placed under anesthesia, the hemodynamic variables were recorded and blood samples were collected. Cardiac hypertrophy was evaluated using the left ventricular weight/body weight ratio, and the collagen volume fraction was assessed using histology. RESULTS: The chronic heart failure trained group showed a reduction in left ventricular end-diastolic pressure, a lower left ventricular weight/body weight ratio and a lower collagen volume fraction compared with the chronic heart failure sedentary group. In addition, exercise training reduced the plasma levels of TNF-α and IL-6 and increased the plasma level of IL-10. CONCLUSION: An 8-week aerobic exercise training program improved the inflammatory profile and cardiac function and attenuated cardiac remodeling in chronic heart failure rats.

Inspiratory muscle training reduces blood pressure and sympathetic activity in hypertensive patients: A randomized controlled trial

BACKGROUND Autonomic imbalance, characterized by sympathetic hyperactivity and diminished vagal tone, is a known mechanism for essential hypertension. Inspiratory muscle training (IMT) demonstrates beneficial outcomes in a number of cardiovascular populations, which may potentially extend to patients with hypertension. The aim of this study was to further elucidate the effects of IMT on blood pressure and autonomic cardiovascular control in patients with essential hypertension. METHODS Thirteen patients with hypertension were randomly assigned to an eight-week IMT program (6 patients) or to a placebo-IMT (P-IMT, 7 patients) protocol. We recorded RR interval for posterior analysis of heart rate variability and blood pressure, by ambulatory blood pressure monitoring (ABPM), before and after the program. RESULTS There was a significant increase in inspiratory muscle strength in the IMT group (82.7 ± 28.8 vs 121.5 ± 21.8 cmH2O, P<0.001), which was not demonstrated by P-IMT (93.3 ± 25.3 vs 106.1 ± 25.3 cmH2O, P>0.05). There was also a reduction in 24-hour measurement of systolic (133.2 ± 9.9 vs 125.2 ± 13.0 mm Hg, P=0.02) and diastolic (80.7 ± 12.3 vs 75.2 ± 1.0 mm Hg, P=0.02) blood pressure, as well as in daytime systolic (136.8 ± 12.2 vs 127.6 ± 14.2 mm Hg, P=0.008) and diastolic (83.3 ± 13.1 vs. 77.2 ± 12.2 mm Hg, P =0.01) blood pressure in the IMT group. In relation to autonomic cardiovascular control, we found increased parasympathetic modulation (HF: 75.5 ± 14.6 vs. 84.74 ± 7.55 n.u, P=0.028) and reduced sympathetic modulation (LF: 34.67 ± 20.38 vs. 12.81 ± 6.68 n.u; P=0.005). Moreover, there was reduction of cardiac sympathetic discharge (fLF) in IMT group (P=0.01). CONCLUSIONS IMT demonstrates beneficial effects on systolic and diastolic blood pressure as well as autonomic cardiovascular control in hypertensive patients.

Electrical stimulation and electromagnetic field use in patients with diabetic neuropathy: systematic review and meta-analysis

BACKGROUND Painful diabetic neuropathy (PDN) is a common complication of diabetes mellitus, and pharmacological therapies are ineffective in many patients. Therefore, other treatment modalities should be considered, including electrical stimulation and electromagnetic fields. OBJECTIVES The research objective was to evaluate the effect of treatment with electrical stimulation and electromagnetic fields on pain and sensitivity in patients with painful diabetic neuropathy compared with placebo or another intervention. METHOD We searched the following electronic databases (from inception to April 2012): MEDLINE (accessed by PubMed), LILACS, Physiotherapy Evidence Database (PEDro), EMBASE and Cochrane CENTRAL. We included randomized trials that compared electrical stimulation or electromagnetic fields with control groups in which the objective was to assess pain and sensitivity in patients with PDN. Two reviewers independently extracted the data. A random-effects model was used for the main analysis. RESULTS The search retrieved 1336 articles, of which 12 studies were included. Reductions in the mean pain score were significantly greater in the TENS (transcutaneous electrical nerve stimulation) group than in the placebo group [-0.44 (95% CI: -0.79 to -0.09; I2: 0%)]. There was no improvement in pain relief when electromagnetic fields were compared with the control group [-0.69 (95% CI: -1.86 to 0.48; I2: 63%)]. CONCLUSIONS We found that TENS improved pain relief in patients with diabetic neuropathy, while no such improvement was observed with the use of electromagnetic field treatment. Due to the methodological differences between the studies, a meta-analysis for the outcome of sensitivity could not be performed.

Resistance Training Improves Hemodynamic Function, Collagen Deposition and Inflammatory Profiles: Experimental Model of Heart Failure

The role of resistance training on collagen deposition, the inflammatory profile and muscle weakness in heart failure remains unclear. Therefore, this study evaluated the influence of a resistance training program on hemodynamic function, maximum strength gain, collagen deposition and inflammatory profile in chronic heart failure rats. Thirty-two male Wistar rats submitted to myocardial infarction by coronary artery ligation or sham surgery were assigned into four groups: sedentary sham (S-Sham, n = 8); trained sham (T-Sham, n = 8); sedentary chronic heart failure (S-CHF, n = 8) and trained chronic heart failure (T-CHF, n = 8). The maximum strength capacity was evaluated by the one maximum repetition test. Trained groups were submitted to an 8-week resistance training program (4 days/week, 4 sets of 10–12 repetitions/session, at 65% to 75% of one maximum repetition). After 8 weeks of the resistance training program, the T-CHF group showed lower left ventricular end diastolic pressure (P<0.001), higher left ventricular systolic pressure (P<0.05), higher systolic blood pressure (P<0.05), an improvement in the maximal positive derivative of ventricular pressure (P<0.05) and maximal negative derivative of ventricular pressure (P<0.05) when compared to the S-CHF group; no differences were observed when compared to Sham groups. In addition, resistance training was able to reduce myocardial hypertrophy (P<0.05), left ventricular total collagen volume fraction (P<0.01), IL-6 (P<0.05), and TNF-α/IL-10 ratio (P<0.05), as well as increasing IL-10 (P<0.05) in chronic heart failure rats when compared to the S-CHF group. Eight weeks of resistance training promotes an improvement of cardiac function, strength gain, collagen deposition and inflammatory profile in chronic heart failure rats.

Transcutaneous electrical nerve stimulation at different frequencies on heart rate variability in healthy subjects

Sympathetic and parasympathetic nervous system imbalance has been strongly associated to sudden cardiac death. Among the non-pharmacological treatment, transcutaneous electrical nerve stimulation (TENS) represents a possible therapeutic intervention to reduce sympathetic excitation and improve the sympatho-vagal balance in different clinical conditions. We aimed to verify acute effects of high and low transcutaneous electrical nerve stimulation (TENS) frequencies by the evaluation of heart rate variability. Seven healthy volunteers received an application of low frequency (10-Hz) and high frequency (100-Hz) TENS. After 10-Hz, there was decrease of LF normalized units (n.u.) component (32.7±5.9 vs 18.3±3.4, p<0.002) and increase of HF n.u. (60.9±4.3 vs 72.6±8.9, p<0.016). In contrast, after 100-Hz there was increase of LF n.u. (31.5±16.1 vs 41.6±12.2, p<0.019) and reduction of HF n.u. (63.9±15.3 vs 53.7±12.3, p<0.031). In conclusion, TENS modulates sympathetic and parasympathetic activity in a frequency dependent manner.

Cardiac rehabilitation programme after transcatheter aortic valve implantation versus surgical aortic valve replacement: Systematic review and meta-analysis:

Background Aortic stenosis is a valvular heart disease characterised by fixed obstruction of the left ventricular outflow. It can be managed by surgical aortic valve replacement (sAVR) or transcatheter aortic valve implantation (TAVI). This review aimed to describe the evidence supporting a cardiac rehabilitation programme on functional capacity and quality of life in aortic stenosis patients after sAVR or TAVI. Methods The search was conducted on multiple databases from January to March 2016. All studies were eligible that evaluated the effects of a post-interventional cardiac rehabilitation programme in aortic stenosis patients. The methodological quality was assessed using the PEDro scale. Meta-analysis was performed separately by procedure and between procedures. The walked distance during the six-minute walk test (6MWD) and Barthel index were evaluated. The analysis was conducted in Review Manager. Results Five studies were included (292 TAVI and 570 sAVR patients). The meta-analysis showed that a cardiac rehabilitation programme was associated with a significant improvement in 6MWD (0.69 (0.47, 0.91); P < 0.001) and Barthel index (0.80 (0.29, 1.30); P = 0.002) after TAVI and 6MWD (0.79 (0.43, 1.15); P < 0.001) and Barthel index (0.93 (0.67, 1.18); P < 0.001) after sAVR. In addition, the meta-analysis showed that the cardiac rehabilitation programme promoted a similar gain in 6MWD (4.28% (−12.73, 21.29); P = 0.62) and Barthel index (−1.52 points (−4.81, 1.76); P = 0.36) after sAVR or TAVI. Conclusions The cardiac rehabilitation programme improved the functional capacity and quality of life in aortic stenosis patients. Patients who underwent TAVI benefitted with a cardiac rehabilitation programme similar to sAVR patients.

Inspiratory muscle training and quality of life in patients with heart failure: Systematic review of randomized trials

review of randomized trials☆ Graciele Sbruzzi , Pedro Dal Lago , Rodrigo Antonini Ribeiro , Rodrigo Della Mea Plentz a,b,⁎ a Laboratory of Clinical Investigation, Instituto de Cardiologia do Rio Grande do Sul/Fundacao Universitaria de Cardiologia (IC/FUC), Porto Alegre, RS, Brazil b Physical Therapy Department, Universidade Federal de Ciencias da Saude de Porto Alegre (UFCSPA), Porto Alegre, RS, Brazil c Institute of Education and Research, Hospital Moinhos de Vento, Porto Alegre, RS, Brazil