Heart Rate Variability and Cardio-respiratory Coupling During Sleep in Patients Prior to Bariatric Surgery

Obesity is associated with increased cardiac risk of morbidly and mortality and for the development and progression of obstructive sleep apnea (OSA). Severity of obesity negatively affects the heart rate variability (HRV) in patients with indication for bariatric surgery (BS). The purpose of this study is to determine if the severity of obesity alters the autonomic cardiac regulation and the cardio-respiratory coupling during sleep using spectral analysis of HRV and respiration variability signals (RS) in patients prior to BS. Twenty-nine consecutive preoperative BS and ten subjects (controls) underwent polysomnography. The spectral and cross-spectral parameters of the HRV and RS were computed during different sleep stages (SS). Spectral analysis of the HRV and RV indicated lower respiration regularity during sleep and a lower HRV in obese patients (OP) during all SS when compared with controls (p < 0.05). Severely (SO) and super-obese patients (SOP) presented lower values of low frequency/high frequency (LF/HF) ratio and LF power during REM sleep and higher HF power (p < 0.05), while morbidly obese (MO) patients presented lower LF/HF ratio and LF power in SS-S2 and higher HF power when compared to controls (p < 0.05). The cross-spectral parameters showed that SOP presented lower percentage of tachogram power coherent with respiration in SS-S3 when compared to controls (p < 0.05). Patients prior to BS presented altered HRV and RV in all SS. SO, MO, and SOP presented altered cardio-respiratory coupling during sleep, and these alterations are related with severity of obesity and OSA parameters

Is cardiac autonomic modulation during upper limb isometric contraction and Valsalva maneuver impaired in COPD patients?

C&aacute;ssia da Luz Goulart,1 Ramona Cabiddu,2 Paloma de Borba Schneiders,1 Elisabete Antunes San Martin,1 Renata Trimer,3 Audrey Borghi-Silva,2&nbsp;Andr&eacute;a L&uacute;cia Gon&ccedil;alves da Silva4,5 1Course of Physiotherapy, University of Santa Cruz do Sul, Rio Grande do Sul, Brazil; 2Cardiopulmonary Physiotherapy Laboratory, Nucleus of Research in Physical Exercise, Federal University of S&atilde;o Carlos, S&atilde;o&nbsp;Carlos, Brazil; 3Department of Physiotherapy, Federal University of Amazonas, Manaus, AM, Brazil; 4Course of Physiotherapy, Department of Health and Physical Education, University of Santa Cruz do Sul, Rio&nbsp;Grande do Sul, Brazil; 5Pulmonary Rehabilitation Program, Santa Cruz Hospital, Santa Cruz do Sul, Rio Grande do Sul, Brazil Purpose: To evaluate the heart rate variability (HRV) indices and heart rate (HR) responses during isometric contraction (IC) and Valsalva maneuver (VM) in COPD patients. Methods: Twenty-two stable moderate to severe COPD patients were evaluated. R-R intervals were recorded (monitor Polar&reg; S810i) during dominant upper limb IC (2 minutes). Stable signals were analyzed by Kubios HRV&reg; software. Indices of HRV were computed in the time domain (mean HR; square root of the mean squared differences of successive RR intervals [RMSSD] and HRV triangular index [RR tri index]) and in the frequency domain (high frequency [HF]; low frequency [LF] and LF/HF ratio). The HR responses were evaluated at rest, at the peak and at the nadir of the VM (15 seconds). The Valsalva index was also calculated. Results: During IC: time domain indices (mean HR increased [P=0.001], RMSSD, and RR tri index decreased [P=0.005 and P=0.005, respectively]); frequency domain indices (LF increased [P=0.033] and HF decreased [P=0.002]); associations were found between forced expiratory volume in 1 second (FEV1) vs RMSSD (P=0.04; r=&ndash;0.55), FEV1 vs HR (P=0.04; r=&ndash;0.48), forced vital capacity (FVC) vs RMSSD (P=0.05; r=&ndash;0.62), maximum inspiratory pressure (MIP) vs HF (P=0.02; r=0.68). FEV1 and FVC justified 30% of mean HR. During VM: HR increased (P=0.01); the nadir showed normal bradycardic response; the Valsalva index was =0.7. Conclusion: COPD patients responded properly to the upper limb IC and to the VM; however, HR recovery during VM was impaired in these patients. The severity of the disease and MIP were associated with increased parasympathetic modulation and higher chronotropic response. Keywords: heart rate, autonomic nervous system, COPD, isometric contraction, Valsalva maneuve

Heart Rate Variability and Cardio-respiratory Coupling During Sleep in Patients Prior to Bariatric Surgery

Obesity is associated with increased cardiac risk of morbidly and mortality and for the development and progression of obstructive sleep apnea (OSA). Severity of obesity negatively affects the heart rate variability (HRV) in patients with indication for bariatric surgery (BS). The purpose of this study is to determine if the severity of obesity alters the autonomic cardiac regulation and the cardio-respiratory coupling during sleep using spectral analysis of HRV and respiration variability signals (RS) in patients prior to BS. Twenty-nine consecutive preoperative BS and ten subjects (controls) underwent polysomnography. The spectral and cross-spectral parameters of the HRV and RS were computed during different sleep stages (SS). Spectral analysis of the HRV and RV indicated lower respiration regularity during sleep and a lower HRV in obese patients (OP) during all SS when compared with controls (p < 0.05). Severely (SO) and super-obese patients (SOP) presented lower values of low frequency/high frequency (LF/HF) ratio and LF power during REM sleep and higher HF power (p < 0.05), while morbidly obese (MO) patients presented lower LF/HF ratio and LF power in SS-S2 and higher HF power when compared to controls (p < 0.05). The cross-spectral parameters showed that SOP presented lower percentage of tachogram power coherent with respiration in SS-S3 when compared to controls (p < 0.05). Patients prior to BS presented altered HRV and RV in all SS. SO, MO, and SOP presented altered cardio-respiratory coupling during sleep, and these alterations are related with severity of obesity and OSA parameters

Respiratory muscle strength effect on linear and nonlinear heart rate variability parameters in COPD patients

C&aacute;ssia Da Luz Goulart,1 Julio Cristiano Simon,1 Paloma De Borba Schneiders,1 Elisabete Antunes San Martin,1 Ramona Cabiddu,2 Audrey Borghi-Silva,2 Renata Trimer,2 Andr&eacute;a L&uacute;cia Gon&ccedil;alves da Silva1 1Course of Physiotherapy, Department of Health and Physical Education, University of Santa Cruz do Sul (UNISC), Santa Cruz do Sul, Rio Grande do Sul, Brazil; 2Cardiopulmonary Physiotherapy Laboratory, Nucleus of Research in Physical Exercise, Federal University of S&atilde;o Carlos (UFSCar), S&atilde;o Carlos, S&atilde;o Paulo, Brazil Introduction: Chronic obstructive pulmonary disease (COPD) is recognized as a multisystemic inflammatory disease associated with extrapulmonary comorbidities, including respiratory muscle weakness and cardiovascular and cardiac autonomic regulation disorders. We investigated whether alterations in respiratory muscle strength (RMS) would affect cardiac autonomic modulation in COPD patients. Methods: This study was a cross-sectional study done in ten COPD patients affected by moderate to very severe disease. The heart rate variability (HRV) signal was recorded using a Polar cardiofrequencimeter at rest in the sitting position (10 minutes) and during a respiratory sinus arrhythmia maneuver (RSA-M; 4 minutes). Linear analysis in the time and frequency domains and nonlinear analysis were performed on the recorded signals. RMS was assessed using a digital manometer, which provided the maximum inspiratory pressure (Pimax) and the maximum expiratory pressure (Pemax). Results: During the RSA-M, patients presented an HRV power increase in the low-frequency band (LFnu) (46.9&plusmn;23.7 vs 75.8&plusmn;27.2; P=0.01) and a decrease in the high-frequency band (HFnu) (52.8&plusmn;23.5 vs 24.0&plusmn;27.0; P=0.01) when compared to the resting condition. Significant associations were found between RMS and HRV spectral indices: Pimax and LFnu (r=-0.74; P=0.01); Pimax and HFnu (r=0.74; P=0.01); Pemax and LFnu (r=-0.66; P=0.01); Pemax and HFnu (r=0.66; P=0.03); between Pemax and sample entropy (r=0.83; P&lt;0.01) and between Pemax and approximate entropy (r=0.74; P=0.01). Using a linear regression model, we found that Pimax explained 44% of LFnu behavior during the RSA-M. Conclusion: COPD patients with impaired RMS presented altered cardiac autonomic control, characterized by marked sympathetic modulation and a reduced parasympathetic response; reduced HRV complexity was observed during the RSA-M. Keywords: COPD, heart rate, muscle strength, autonomic nervous system, sinus arrhythmi

Chronic obstructive pulmonary disease severity and its association with obstructive sleep apnea syndrome: impact on cardiac autonomic modulation and functional capacity

Katiany Thays Lopes Zangrando,1 Renata Trimer,2 Luiz Carlos Soares de Carvalho Jr,1 Guilherme Peixoto Tinoco Ar&ecirc;as,1 Fl&aacute;via Cristina Rossi Caruso,1 Ramona Cabiddu,1 Meliza Goi Roscani,3 Fab&iacute;ola Paula Galhardo Rizzatti,3 Audrey Borghi-Silva1 1Cardiopulmonary Physiotherapy Laboratory, Physiotherapy Department, Federal University of S&atilde;o Carlos, S&atilde;o Carlos, S&atilde;o Paulo, Brazil; 2Physical Education and Health Department, University of Santa Cruz do Sul, Santa Cruz do Sul, Rio Grande do Sul, Brazil; 3Medicine Department, Federal University of S&atilde;o Carlos, S&atilde;o Carlos, S&atilde;o Paulo, Brazil Background: The study was conducted to determine the impact of chronic obstructive pulmonary disease (COPD) in association with obstructive sleep apnea syndrome (OSAS) on cardiac autonomic control and functional capacity. Subjects and methods: The study was a cross-sectional prospective controlled clinical study. Heart rate variability indices of 24 COPD (n = 12) and COPD+OSAS (n = 12) patients were evaluated and compared by electrocardiographic recordings acquired during rest, active postural maneuver (APM), respiratory sinus arrhythmia maneuver (RSA-m), and the 6-minute walk test (6MWT). Results: The COPD group presented higher parasympathetic modulation during APM when compared to the COPD+OSAS group (P = 0.02). The COPD+OSAS group presented higher sympathetic modulation during RSA-m when compared to the COPD group (P = 0.00). The performance during 6MWT was similarly impaired in both groups, despite the greater severity of the COPD group. Conclusion: Subjects with COPD+OSAS present marked sympathetic modulation, and the presence of OSAS in COPD subjects has a negative impact on functional capacity regardless of the severity of lung disease. Keywords: COPD, OSAS, COPD+OSAS, functional capacit

Does the incremental shuttle walk test require maximal effort in young obese women?

Obesity is a chronic disease with a multifaceted treatment approach that includes nutritional counseling, structured exercise training, and increased daily physical activity. Increased body mass elicits higher cardiovascular, ventilatory and metabolic demands to varying degrees during exercise. With functional capacity assessment, this variability can be evaluated so individualized guidance for exercise training and daily physical activity can be provided. The aim of the present study was to compare cardiovascular, ventilatory and metabolic responses obtained during a symptom-limited cardiopulmonary exercise test (CPX) on a treadmill to responses obtained by the incremental shuttle walk test (ISWT) in obese women and to propose a peak oxygen consumption (VO2) prediction equation through variables obtained during the ISWT. Forty obese women (BMI &#8805;30 kg/m2) performed one treadmill CPX and two ISWTs. Heart rate (HR), arterial blood pressure (ABP) and perceived exertion by the Borg scale were measured at rest, during each stage of the exercise protocol, and throughout the recovery period. The predicted maximal heart rate (HRmax) was calculated (210 &#8211; age in years) (16) and compared to the HR response during the CPX. Peak VO2 obtained during CPX correlated significantly (P<0.05) with ISWT peak VO2 (r=0.79) as well as ISWT distance (r=0.65). The predictive model for CPX peak VO2, using age and ISWT distance explained 67% of the variability. The current study indicates the ISWT may be used to predict aerobic capacity in obese women when CPX is not a viable option

Heart rate variability and cardiorespiratory coupling in obstructive sleep apnea: elderly compared with young

INTRODUCTION: Aging is known to be a major contributing factor to the increased risk of obstructive sleep apnea (OSA). With aging, breathing undergoes significant changes during sleep, increasing the prevalence of apnea events, which affects heart rate variability (HRV) and cardiorespiratory coupling (CRC). OBJECTIVES: To compare HRV and CRC during wakefulness and sleep between young and elderly patients with and without OSA; and to determine whether the presence of OSA in young and elderly patients has a different impact on HRV and CRC during sleep. METHODS: One hundred subjects, 50 young (mean age, 27 ± 9; 20 normal and 30 OSA) and 50 elderly (mean age, 65 ± 7; 20 normal and 30 OSA), underwent polysomnography. Spectral, cross-spectrum, and HRV parameters were analyzed during wakefulness and sleep. RESULTS: The spectral analysis indicated that age affected HRV, with higher values of low frequency (P <0.05) in elderly subjects during wakefulness and an interaction between the presence of OSA and age. OSA influenced HRV during sleep with lower LF/HF ratios during stage 2 (S2) and rapid eye movement (REM) sleep (P <0.05), with an interaction between the presence of OSA and age in REM sleep. Elderly patients had significantly lower percent tachogram power coherent with respiration (%TPCR) during wakefulness (P <0.05), and OSA led to lower %TPCR during S2. CONCLUSIONS: Age and OSA have an unfavorable impact on HRV, with reduced autonomic modulation during wakefulness, S2, and REM sleep. Age affects CRC during wakefulness and the presence of OSA affects CRC during sleep