Michel Silva Reis

Noninvasive ventilation acutely modifies heart rate variability in chronic obstructive pulmonary disease patients.

OBJECTIVEnThe purpose of present study was to evaluate the acute effects of bi-level positive airway pressure (BiPAP) on heart rate variability (HRV) of stable chronic obstructive pulmonary disease patients (COPD).nnnMETHODSnNineteen males with COPD (69+/-8 years and with forced expiratory volume in 1s <50% of predicted) and eight healthy sedentary age-matched (69 years) males in the control group (CG) were evaluated during two conditions of controlled respiratory rate: spontaneous breathing (SB) and BiPAP (inspiratory and expiratory levels between 12-14 cmH(2)O and 4-6 cmH(2)O, respectively). Peripheral oxygen saturation (SpO(2)), end-tidal of carbon dioxide (ETCO(2)), systolic blood pressure (SBP) and R-R interval were obtained. HRV was analyzed by time (RMSSD and SDNN index) and frequency domains (high frequency - HF, low frequency - LF and HF/LF ratio).nnnRESULTSnSignificant reduction of ETCO(2) and SBP in both groups and increase of SpO(2) in COPD group was observed during BiPAP ventilation (p<0.05). During spontaneous breathing, patients with COPD presented lower values of LF, LF/HF and higher values of HF when compared to CG (p<0.05). However, HF was significantly reduced and LF increased during BiPAP ventilation (58+/-19-48+/-15 and 41+/-19-52+/-15 un, respectively) in COPD group. Significant correlations between delta BiPAP-SB (Delta) ETCO(2) and DeltaHF were found (r=0.89).nnnCONCLUSIONSnSympathetic and parasympathetic neural control of heart rate is altered in COPD patients and that BiPAP acutely improves ventilation, enhances sympathetic response and decreases vagal tonus. The improvement of ventilation caused by BiPAP was associated with reduced cardiac vagal activity in stable moderate-to-severe COPD patients.

Acute effects of different levels of continuous positive airway pressure on cardiac autonomic modulation in chronic heart failure and chronic obstructive pulmonary disease

Introduction Non-invasive ventilation may improve autonomic modulation and ventilatory parameters in severely disabled patients. The aim of the present study was to evaluate the physiological influence of acute treatment with different levels of continuous positive airway pressure (CPAP) on the autonomic balance of heart and respiratory responses in patients with stable chronic obstructive pulmonary disease (COPD) and chronic heart failure (CHF). Materials and methods A COPD group (n = 10), CHF group (n = 8) and healthy subjects (n = 10) were evaluated. The participants were randomized to receive three different levels of CPAP on the same day: sham ventilation (Sham), 5 cmH20 (CPAP5) and 10 cmH20 (CPAP10) for 10 min. Respiratory rate, end tidal carbon dioxide (ETCO2), peripheral oxygen saturation (SpO2), heart rate (HR), blood pressure and heart rate variability in the time and frequency domains were measured during spontaneous breathing and under the sham, CPAP5 and CPAP10 conditions. Results All groups experienced a reduction in ETCO2 values during treatment with CPAP (p < 0.05). CPAP increased SpO2 and HR in the COPD group (p < 0.05). The COPD group also had lower RMSSD values during treatment with different levels of CPAP when compared to the control group (p < 0.05). In the CHF group, CPAP5 and CPAP10 increased the SDNN value (p < 0.05). CPAP10 reduced the SDNN value in the COPD group (p < 0.05). Conclusion The findings suggest that CPAP may cause improvements in the neural control of heart rate in patients with stable COPD and CHF. For each patient, the “best CPAP level” should be defined as the best respiratory response and autonomic balance.

Deep breathing heart rate variability is associated with respiratory muscle weakness in patients with chronic obstructive pulmonary disease

BACKGROUND A synchronism exists between the respiratory and cardiac cycles. However, the influence of the inspiratory muscle weakness in chronic obstructive pulmonary disease (COPD) on cardiac autonomic control is unknown. The purpose of the present investigation was to evaluate the influence of respiratory muscle strength on autonomic control in these patients. METHODS Ten chronic obstructive pulmonary disease patients (69±9 years; FEV1/FVC 59±12% and FEV1 41±11% predicted) and nine age-matched healthy volunteers (64±5 years) participated in this study. Heart-rate variability (HRV) was obtained at rest and during respiratory sinusal arrhythmia maneuver (RSA-M) by electrocardiograph. RESULTS Chronic obstructive pulmonary disease patients demonstrated impaired cardiac autonomic modulation at rest and during RSA-M when compared with healthy subjects (p<0.05). Moreover, significant and positive correlations between maximal inspiratory pressure (MIP) and the inspiratory-expiratory difference (ΔIE) (r = 0.60, p<0.01) were found. CONCLUSION Patients with chronic obstructive pulmonary disease presented impaired sympathetic-vagal balance at rest. In addition, cardiac autonomic control of heart rate was associated with inspiratory muscle weakness in chronic obstructive pulmonary disease. Based on this evidence, future research applications of respiratory muscle training may bring to light a potentially valuable target for rehabilitation.

Multiscale recurrent pattern image coding with a flexible partition scheme

In this paper we present a new segmentation method for the multidimensional multiscale parser (MMP) algorithm. In previous works we have shown that, for text and compound images, MMP has better compression efficiency than state-of-the-art transform-based encoders like JPEG2000 and H.264/AVC; however, it is still inferior to them for smooth images. In this paper we improve the performance of MMP for smooth images by employing a more flexible block segmentation scheme than the one defined in the original algorithm. The new partition scheme allows MMP to exploit the images structure in a much more adaptive and effective way. Experimental tests have shown consistent performance gains, mainly for smooth images. When employing the new block segmentation scheme, MMP outperforms the state-of-the-art JPEG2000 and H.264/AVC Intra-frame image coding algorithms for both smooth and non-smooth images, at low to medium compression ratios.

Controle autonômico da frequência cardíaca de pacientes com doenças cardiorrespiratórias crônicas e indivíduos saudáveis em repouso e durante a manobra de acentuação da arritmia sinusal respiratória

OBJECTIVE: To evaluate the autonomic modulation of heart rate (HR) at rest in the supine position and during a respiratory sinus arrhythmia maneuver (M-RSA) among participants with chronic obstructive pulmonary disease (COPD) or with chronic heart failure (CHF). METHODS: Twenty-eight men were divided into three groups: ten with COPD, aged 69±9 years; nine with CHF, aged 62±8 years; and nine healthy participants aged 64±5 years (controls). At rest, the R-R interval of the electrocardiographic signal was obtained in the following situations: 1) 15 min in the supine position; and 2) 4 min during M-RSA in the supine position. The data were analyzed in the time domain (RMSSD and SDNN indices) and the frequency domain (LFab and HFab). During M-RSA, the expiratory/inspiratory ratio (E/I) and the inspiratory/expiratory difference (∆IE) were calculated. RESULTS: The main findings showed that the CHF patients presented lower RMSSD (12.2±2.6 vs. 20.4±6.5), LFab (99.2±72.7 vs. 305.3±208.9) and HFab (53.4±29.9 vs. 178.9±113.1), compared with the controls. The LFab band was significantly lower in the COPD group than in the controls (133.8±145.5 vs. 305.3±208.9). Additionally, both CHF patients and COPD patients showed lower E/I ratios (1.1±0.06 vs. 1.2±0.1 and 1.1±0.03 vs. 1.2±0.1) and ∆IE values (7.0±3.5 vs. 12.7±0.1 and 4.9±1.6 vs. 12.7±0.1), respectively, compared with the controls during M-RSA. CONCLUSION: The results from this study suggest that both COPD and CHF have a negative impact on the autonomic control of heart rate. Article registered on the Australian New Zealand Clinical Trials Registry (ANZCTR) under the number: ACTRN12609000467235

Relationship between oxygen consumption kinetics and BODE Index in COPD patients

Background and objective Patients with chronic obstructive pulmonary disease (COPD) present with reduced exercise capacity due to impaired oxygen consumption (VO2), caused primarily by pulmonary dysfunction and deleterious peripheral adaptations. Assuming that COPD patients present with slower VO2 and heart rate (HR) on-kinetics, we hypothesized that this finding is related to disease severity as measured by the BODE Index. In this context, the present study intends to evaluate the relationship between VO2 uptake on-kinetics during high-intensity exercise and the BODE Index in patients with COPD. Methods Twenty males with moderate-to-severe stable COPD and 13 healthy control subjects matched by age and sex were evaluated. COPD patients were screened by the BODE Index and then underwent an incremental cardiopulmonary exercise test and a constant speed treadmill session at 70% of maximal intensity for 6 minutes. The onset of the exercise (first 360 seconds) response for O2 uptake and HR was modeled according to a monoexponential fit. Results Oxygen consumption and HR on-kinetics were slower in the COPD group compared with controls. Additionally, VO2 on-kinetic parameters revealed a strong positive correlation (r = 0.77, P < 0.05) with BODE scores and a moderate negative correlation with walking distance (r = −0.45, P < 0.05). Conclusion Our data show that moderate-to-severe COPD is related to impaired oxygen delivery and utilization during the onset of intense exercise.

Heart rate autonomic responses during deep breathing and walking in hospitalised patients with chronic heart failure

Objective.u2003To evaluate the acute effect of physiotherapy (deep breathing exercises and walking) on heart rate variability in patients hospitalised with chronic heart failure (CHF). Design.u2003Ten males with CHF (57u200a±u200a7 years) and 10 healthy controls (59u200a±u200a9 years) were included. Heart rate and RR intervals were recorded in the following conditions: supine, seated, during deep breathing exercises and during and after walking. Heart rate variability was analysed by linear and non-linear methods (α2, Mean HR, rMSSD, SDNN and ApEn). Results.u2003Patients presented significantly lower SDNN (12.4u200a±u200a4 versus 26u200a±u200a8u2009ms), rMSSD (18.2u200a±u200a16.2 versus 25u200a±u200a19.5u2009ms) and ApEn (9.9u200a±u200a10 versus 16.68u200a±u200a22.6) during the walking compared to controls (pu200a<u200a0.05). In addition, mean HR was significantly higher during and after walking for patients with CHF compared to controls (103u200a±u200a8 versus 80u200a±u200a2 bpm and 90u200a±u200a9 versus 68u200a±u200a2 bpm, respectively). Patients with CHF demonstrated a significant reduction of α2 during deep breathing (0.78u200a±u200a0.1) when compared to the seated position (1.08u200a±u200a0.1) and walking (1.15u200a±u200a0.2, pu200a<u200a0.05). Additionally, rMSSD index increased during deep breathing when compared to walking in both groups. Conclusion.u2003Deep breathing exercises and walking are safe and promote beneficial effects on heart rate variability in patients hospitalised for CHF.

Association of Oscillatory Ventilation during Cardiopulmonary Test to Clinical and Functional Variables of Chronic Heart Failure Patients

Objective The aim of this study is to characterize the presence of exercise oscillatory ventilation (EOV) and to relate it with other cardiopulmonary exercise test (CET) responses and clinical variables. Methods Forty-six male patients (age: 53.1±13.6 years old; left ventricular ejection fraction [LVEF]: 30±8%) with heart failure were recruited to perform a maximal CET and to correlate the CET responses with clinical variables. The EOV was obtained according to Leite et al. criteria and VE/VCO2 > 34 and peak VO2 < 14 ml/kg/min were used to assess patients severity. Results The EOV was observed in 16 of 24 patients who performed the CET, as well as VE/VCO2 > 34 and peak VO2 < 14 ml/kg/min in 14 and 10 patients, respectively. There was no difference in clinical and CET variables of the patients who presented EOV in CET when compared to non-EOV patients. Also, there was no difference in CET and clinical variables when comparing patients who presented EOV and had a VE/VCO2 slope > 34 to patients who just had one of these responses either. Conclusion The present study showed that there was an incidence of patients with EOV and lower peak VO2 and higher VE/VCO2 slope values, but they showed no difference on other prognostic variables. As well, there was no influence of the presence of EOV on other parameters of CET in this population, suggesting that this variable may be an independent marker of worst prognosis in HF patients.

Determinação do limiar anaeróbio pela variabilidade da frequência cardíaca de pacientes com DPOC durante exercício em cicloergômetro

Abstract Introduction : Chronic Obstructive Pulmonary Disease (COPD) is characterized by structural alterations of lung parenchyma resulting in systemic manifestations. These patients may have marked change in cardiac au-tonomic control. In this context, studies investigating heart rate variability (HRV) in patients with COPD during physical exercise cycloergometers have been little explored. Objective : To determine the anaerobic threshold through HRV in order to establish parameters of evaluation and prescription of exercise intensity in these patients on a cycloergometer. Materials and methods : Eight male patients diagnosed with COPD, mean age 69.5 ± 7.6 years were studied. Heart rate was analyzed at rest and at different intensities of exercise. The test was performed on a cycloergometer and consisted of a warm-up period of four minutes at a minimum power. Steps were performed with initial power of 4W, with increments of 5 in 5W, until the patient reached the an-aerobic threshold.

Study of heart rate autonomic modulation at rest in elderly patients with chronic obstructive pulmonary disease

OBJECTIVE: To evaluate heart rate variability (HRV) among elderly patients with chronic obstructive pulmonary disease (COPD) and healthy elderly individuals, during postural change. METHOD: Nine individuals with COPD (70 years old) and eight healthy individuals (68 years old) were studied. Heart rate and electrocardiographic R-R intervals (iR-R) were recorded for 360 seconds in the supine and seated positions. HRV was analyzed in the time domain (TD) (RMSSD index, i.e. the root mean square of the squares of the differences between successive iR-R records, and the SDNN index, i.e. the mean standard deviation of normal iR-R in ms) and in the frequency domain (FD), from the low-frequency (LF) and high-frequency (HF) bands in absolute units (au) and normalized units (nu), and the LF/HF ratio. The Mann-Whitney and Wilcoxon Tests respectively were utilized for inter--group and intra-group analysis, with a significant level of p< 0.05 (median values). RESULTS: In TD, the control group (CG) presented significantly higher values for the RMSSD index (14.6 versus 8.3 ms) and the SDNN index (23 versus 13.5 ms) in the seated position, in comparison with the COPD group (DG). In FD, the CG presented significantly higher values for HF components, in the supine position (39 versus 7.8 au), and for LF components (146.7 versus 24.4 au) and HF (67.6 versus 22.7 au), in the seated position, as well as for the total power spectrum (552.5 versus 182.9 ms2). CONCLUSION: Patients with COPD presented reduced HRV with decreased sympathetic and vagal activity. Additionally, neither the COPD patients nor the healthy elderly participants presented autonomic alterations with postural change.Objective: To evaluate heart rate variability (HRV) among elderly patients with chronic obstructive pulmonary disease (COPD) and healthy elderly individuals, during postural change. Method: Nine individuals with COPD (70 years old) and eight healthy individuals (68 years old) were studied. Heart rate and electrocardiographic R-R intervals (iR-R) were recorded for 360 seconds in the supine and seated positions. HRV was analyzed in the time domain (TD) (RMSSD index, i.e. the root mean square of the squares of the differences between successive iR-R records, and the SDNN index, i.e. the mean standard deviation of normal iR-R in ms) and in the frequency domain (FD), from the low-frequency (LF) and high-frequency (HF) bands in absolute units (au) and normalized units (nu), and the LF/HF ratio. The Mann-Whitney and Wilcoxon Tests respectively were utilized for intergroup and intra-group analysis, with a significant level of p< 0.05 (median values). Results: In TD, the control group (CG) presented significantly higher values for the RMSSD index (14.6 versus 8.3 ms) and the SDNN index (23 versus 13.5 ms) in the seated position, in comparison with the COPD group (DG). In FD, the CG presented significantly higher values for HF components, in the supine position (39 versus 7.8 au), and for LF components (146.7 versus 24.4 au) and HF (67.6 versus 22.7 au), in the seated position, as well as for the total power spectrum (552.5 versus 182.9 ms 2 ). Conclusion: Patients with COPD presented reduced HRV with decreased sympathetic and vagal activity. Additionally, neither the COPD patients nor the healthy elderly participants presented autonomic alterations with postural change.