Effect of Dynamic Hyperinflation on Cardiac Response to Exercise of Patients With Chronic Obstructive Pulmonary Disease

IntroductionAlthough the major limitation to exercise performance in patients with COPD is dynamic hyperinflation (DH), little is known about its relation with cardiac response to exercise. Our objectives were to compare the exercise response of stroke volume (SV) and cardiac output (CO) between COPD patients with or without DH and control subjects, and to assess the main determinants.MethodsFifty-seven stable COPD patients without cardiac comorbidity and 25 healthy subjects were recruited. Clinical evaluation, baseline function tests, computed tomography and echocardiography were conducted in all subjects. Patients performed consecutive incremental exercise tests with measurement of operating lung volumes and non-invasive measurement of SV, CO and oxygen uptake (VO₂) by an inert gas rebreathing method. Biomarkers of systemic inflammation and oxidative stress, tissue damage/repair, cardiac involvement and airway inflammation were measured.ResultsCOPD patients showed a lower SV/VO₂ slope than control subjects, while CO response was compensated by a higher heart rate increase. COPD patients with DH experienced a reduction of SV/VO₂ and CO/VO₂ compared to those without DH. In COPD patients, the end-expiratory lung volume (EELV) increase was related to SV/VO₂ and CO/VO₂ slopes, and it was the only independent predictor of cardiac response to exercise. However, in the regression models without EELV, plasma IL-1β and high-sensitivity cardiac troponin T were also retained as independent predictors of SV/VO₂ slope.ConclusionDynamic hyperinflation decreases the cardiac response to exercise of COPD patients. This effect is related to systemic inflammation and myocardial stress but not with left ventricle diastolic dysfunction.     

6分钟步行试验在心力衰竭患者心功能评价中的应用

本文就6min步行试验的适应证、相关因素及临床应用最新进展作一综述。     

Effect of Terbutaline on Exercise Capacity and Pulmonary Function in Patients with Chronic Obstructive Pulmonary Disease

The objective of this study was to investigate the effects of a single dose of a β₂-agonist, terbutaline (Bricanyl Turbuhaler?), on resting lung function and exercise capacity in patients with chronic obstructive lung disease. Using a double-blind, placebo-controlled, randomized crossover study and outpatients from a department of pulmonary medicine at a major inner-city hospital, we examined 26 individuals with chronic obstructive lung disease who met the criteria of 40% ≤ FEV₁≤ 70% of predicted, FEV₁/FVC ≤ 70%, and ΔFEV₁≤ 200 ml 20 min after inhalation of 1 mg of terbutaline. The patients inhaled 2.5 mg of terbutaline and matched placebo. At rest, terbutaline caused significant increases in D_LCO, MVV_12sec, and all spirometric indices derived from the flow-volume loop, the increases also being significantly larger than those after inhalation of 1 mg of terbutaline for FEV₁, FVC, and PEF. The peak work rate was unchanged after terbutaline. Oxygen uptake, ventilation, and tidal volume at peak work rate increased significantly, whereas carbon dioxide elimination increased insignificantly. Cumulative oxygen uptake and carbon dioxide elimination during progressive exercise to exhaustion and 10 min of recovery were significantly higher after terbutaline. We concluded that despite significant improvements in resting lung function, inhalation of 2.5 mg of terbutaline did not increase exercise capacity, but it increased cumulative oxygen uptake and carbon dioxide elimination during exercise and recovery, presumably because of a thermogenic effect of terbutaline. Accepted for publication: 29 April 1999     

Exercise Capacity and Activities of Daily Living are Related in Patients With Chronic Obstructive Pulmonary Disease

IntroductionThe knowledge of the relationship between exercise capacity and activities of daily living (ADLs) is important to minimize the negative outcomes in ADLs resulting from reduced exercise capacity in patients with chronic obstructive pulmonary disease (COPD). There is a limited study about the association between exercise capacity and ADLs in patients with COPD. This study aimed to investigate the relationship between maximal exercise capacity and ADLs in patients with GOLD stage II–III COPD.MethodsTwenty-seven clinically stable GOLD stage II–III COPD patients were included (mean age = 58.59 ± 9.63 years and mean FEV₁ = 50.6 ± 13.7%) in this cross-sectional study. Maximal and submaximal exercise capacity were evaluated using an incremental shuttle walk test (ISWT) and 6-min walk test (6MWT), respectively. Activities of daily living were assessed using Glittre-ADL test.ResultsThe ISWT distance was significantly correlated with Glittre-ADL test time (r = −0.517, p = 0.006). There was also a negative correlation between 6MWT distance and Glittre-ADL test time (r = −0.506, p = 0.007).ConclusionA moderate relationship was found between maximal exercise capacity and general activities of daily living performance. The reduction in exercise capacity increases the negative influences in ADLs and strengthens our beliefs that exercise interventions in pulmonary rehabilitation could influence activities of daily living positively.     

Physical Activity Patterns in Patients in Different Stages of Chronic Obstructive Pulmonary Disease

It has previously been suggested that exercise capacity is decreased in COPD and that it is associated with degree of disease. The reduced exercise capacity may plausibly be due to low levels of physical activity in this patient group. The aim of the present study was to assess exercise capacity and physical activity in different stages of COPD and to examine the associations between exercise capacity, pulmonary function and degree of physical activity. A total of 44 COPD patients and 17 healthy subjects participated in the study. Exercise capacity was assessed using the 6-minute walking test and physical activity was assessed using an accelerometer worn all waking hours during 7 days. Mean exercise capacity was significantly lower in COPD patients compared with healthy subjects. Mean physical activity level and time spent at least moderately active were significantly lower in patients with moderate and severe COPD compared with healthy subjects while no differences in time spent sedentary were observed between the study groups. Pulmonary function, mean physical activity level and time spent at least moderately physically active were significantly associated with exercise capacity in the patients. We conclude that patients with moderate and severe COPD are less physically active compared with healthy subjects. Furthermore, mean physical activity level and physical activity of at least moderate intensity are positively associated with exercise capacity in COPD, while time spent sedentary is not, which stresses an important role of physical activity on exercise capacity in these patients.     

Heart Rate Variability and Disease Characteristics in Patients with COPD

Heart rate variability (HRV) is reduced in patients with chronic obstructive pulmonary disease (COPD). However, the relationships among HRV and characteristics of COPD are unknown. The aim of this study was to characterize HRV in patients with COPD and to verify the correlation of HRV measured during rest with disease severity and pulmonary, muscular, and functional impairment. Thirty-one patients with COPD (16 male; 66 +/- 8 years; BMI = 24 +/- 6 kg/m(2); FEV(1) = 46 +/- 16% predicted) without severe cardiac dysfunction were included. HRV assessment was performed by the head-up tilt test (HUTT), and the main variables used for analysis were SDNN index, LF/HF ratio, and R-R intervals. Other tests included spirometry, bioelectrical impedance, cardiopulmonary exercise test, 6-minute walk test, respiratory and peripheral muscle force, health-related quality of life and functional status questionnaires, and objective quantification of physical activity level in daily life with the DynaPort and SenseWear armband activity monitors, besides calculation of the BODE index. There was a statistical difference in all variables of HRV between the HUTT positions (lying and standing). There was no correlation of HRV with BODE index or FEV(1). Out of the BODE index, just the BMI was correlated with SDNN and R-R intervals (r = 0.44; p < 0.05 and r = 0.37; p < 0.05, respectively). There was correlation between HRV reduction and a lower level of physical activity in daily life, besides worse health-related quality of life, functional status, and respiratory and peripheral muscle force. Cardiac autonomic function of patients with COPD is not related to disease severity but mainly to the level of physical activity in daily life.     

Obesity and Functioning Among Individuals with Chronic Obstructive Pulmonary Disease (COPD)

In COPD, body composition studies have focused primarily on low BMI. We examined obesity (BMI ≥ 30 kg/m²) as a risk factor for poor function and longitudinal functional decline. Data from a longitudinal cohort of adults with COPD (n = 1096) and an age- and sex-matched comparison group collected in two in-person visits ～49 months apart were analyzed. Two measures of functioning were examined: six-minute walk distance (6MWD) and Short Physical Performance Battery (SPPB). Multivariate regression analyses examined relationships of obesity with functioning. Secondary analyses stratified by GOLD classification (GOLD-0/1, GOLD-2, GOLD-3/4). Obesity (53% of COPD cohort) was associated cross-sectionally with 6MWD and SPPB in COPD, and only with 6MWD in the comparison group. Obesity predicted significant functional decline in 6MWD for individuals with COPD (odds ratio (OR) for decline [95% CI] 1.8 [1.1, 2.9]), but not the comparison group. Secondary analyses revealed that the risk of decline was significant only in those with more severe COPD (GOLD 3/4, OR = 2.3 [1.0, 5.4]). Obesity was highly prevalent and was associated with poor function concurrently and with subsequent decline in 6MWD in COPD. Obesity in COPD should be considered a risk not only for more co-morbidities and greater health care use, but also for functional decline.     

肠易激综合征患者心血管自主神经功能变化与心率变异性的关系

目的 :探讨肠易激综合征 (1BS)患者心血管自主神经功能变化与心率变异性 (HRV)的关系。方法 :对IBS患者 50例进行标准心血管自主神经功能测试 ,将其结果分成阳性组 (DNA+ )及阴性组 (DNA- ) ,健康人 30名为对照组。 2 4h动态心电图进行HRV分析。结果 :IBS患者自主神经功能异常的发生率为 58% ,主要表现为迷走神经功能异常 ;HRV时域分析中DNA+ 组SDNN、SDANN、SDNNindex明显减少 ;DNA+ 及DNA- 组中反映副交感神经张力的RMSSD、PNN50 、HF等指标明显增高 ,LF/HF比值明显减低 ,与对照组比较有显著性差异 (P <0 .0 5)。结论 :IBS患者存在副交感神经张力增加。HRV分析是发现IBS患者自主神经功能异常的较好方法     

Effects of Pulmonary Hypertension on Exercise Capacity in Patients With Chronic Obstructive Pulmonary Disease

IntroductionThe impact of pulmonary hypertension (PH) on exercise tolerance in chronic obstructive pulmonary disease (COPD) has not been fully elucidated. It is necessary to characterize pulmonary hemodynamics in patients with moderate to severe COPD in order to improve their management. The aim of the study was to determine whether in COPD the presence of PH is associated with reduced exercise tolerance in a cohort of stable COPD patients.MethodsCross-sectional analysis of 174 COPD patients clinically stable: 109 without PH and 65 with PH (COPD-PH). We assessed socio-demographic data, lung function, quality of life, dyspnea, cardiopulmonary exercise testing (CPET), constant workload endurance time (CWET), and six-minute walk test (6MWT). We elaborated a logistic regression model to explore the impact of PH on exercise capacity in COPD patients.ResultsCOPD-PH patients showed lower exercise capacity both at maximal (CPET) (43(20) versus 68(27) Watts and 50(19)% versus 71(18)% predicted peak oxygen consumption (VO₂peak), COPD-PH and COPD, respectively), and at submaximal tests (6MWT) (382(94) versus 486(95) m). In addition, the COPD-PH group had lower endurance time than the non-PH COPD group (265(113) s and 295(164) s, respectively).ConclusionsThe presence of PH is an independent factor that impairs exercise capacity in COPD.     

Chronotropic Incompetence and its Relation to Exercise Intolerance in Chronic Obstructive Pulmonary Disease

Background

To study the relationship between chronotropic incompetence (CI) and disease severity and to assess the effect of CI on exercise capacity in patients with chronic obstructive pulmonary disease (COPD).

Abnormal Response to Exercise in Middle-aged NIDDM Patients with and without Autonomic Neuropathy

The cardiovascular response to exercise in middle-aged non-insulin-dependent diabetes mellitus (NIDDM) patients and the potential role of clinical characteristics and autonomic function were evaluated. One hundred and eight NIDDM patients, aged 40–65 years, were compared with a control group of 112 subjects, matched by age, sex, physical fitness, and presence of hypertension. All subjects performed a maximal exercise test. The diabetic patients completed cardiovascular autonomic neuropathy (CAN) tests: deep breathing, postural hypotension and lying to standing. There were no significant differences in total work capacity, heart rate, and blood pressure, either at rest or at peak exercise between the two groups. Diabetic patients showed significantly lower values of systolic and diastolic blood pressure during exercise, significantly slower recovery of heart rate (at 5th minute the average values were 102.7 ± 14.1 beats min⁻¹ vs 91.9 ± 11.1, p < 0.001); and significantly higher proportion of blunted increase of heart rate (9.2 % vs 0.9 %, p < 0.001) and systolic blood pressure (9.2 % vs 0.7 %, p < 0.001) during exercise. No correlation between the exercise results and the main clinical characteristic (presence of hypertension, BMI, duration of diabetes, treatment, microalbuminuria, total score of CAN) was observed. These findings suggest that the cardiovascular response to exercise could be impaired also in the absence of signs of CAN. This impairment was higher in patients showing a dysfunction of orthosympathetic activity.     

Peptic Ulceration in Patients with Chronic Obstructive Pulmonary Disease

Chronic obstructive pulmonary disease (COPD) is frequently accompanied by peptic ulceration. Recent studies strongly suggest that the major cause is hypersecretion of gastric juice induced by hypoxemia or hypercapnia. To determine the incidence of peptic ulcers in COPD, we surveyed 267 patients with COPD seen at our hospital as inpatients or outpatients between 1984 and 1988. There were 90 patients with pulmonary emphysema, 93 with chronic bronchitis, and 84 with bronchiectasis. The prevalence of gastric ulcer in the patients with COPD was 23 out of the 267 patients (8.6%) surveyed. These included 13 patients with pulmonary emphysema, 6 with chronic bronchitis, and 4 with bronchiectasis. One-half of the patients with pulmonary emphysema had hypoxemia and hypercapnia: These observations suggest it is necessary to improve the abnormal blood gas concentration in patients with COPD in order to promote the healing of the peptic ulcer.     

Cardiovascular Autonomic Function in Patients with Primary Achalasia

Impaired gastrointestinal function outside the esophagus has been found in achalasic patients. Moreover, achalasia may occur in diseases in which a systemic dysautonomia is evident. These findings raise the question of whether a generalized subclinical alteration of autonomic control is also present in primary achalasia. Cardiovascular reflex tests and power spectral analysis of heart rate variability were studied in patients with primary achalasia to establish whether autonomic nervous system changes are present in districts other than the gastrointestinal tract. Nineteen normotensive patients with untreated primary achalasia and with no history of cardiac, renal, or endocrinological diseases were examined. Cardiovascular reflex tests included: the tilt test (10 min at 65°), Valsalva maneuver (40 mm Hg for 15 sec), deep breathing (6 breaths/min), and sustained handgrip (30% of maximal effort for 5 min). The parameters evaluated were systolic and diastolic blood pressure (continuously recorded), ECG, oronasal and thoracic respiration, tachogram, and plethysmogram. To evaluate the balance between parasympathetic and sympathetic functions, power spectral analysis of the heart rate variability was carried out. Each patient was paired with two sex- and age-matched healthy controls. In achalasic patients the head-up tilt test, Valsalva maneuver, deep breathing test, and sustained handgrip did not show significant differences from the control group. Low-frequency (LF) and high-frequency (HF) spectral powers and the ratio of LF to HF did not differ in both groups. This study failed to disclose impaired cardiovascular autonomic control in achalasic patients. We suggest that in primary achalasia the defect is limited to the gastrointestinal tract.     

Pulmonary Function and Ventilatory Limitation to Exercise in Congenital Heart Disease

Pulmonary function in older children and adolescents following surgical repair of congenital heart disease is often abnormal for various reasons. Many of these patients report symptoms of exercise intolerance although the reason(s) for this symptom can be complicated and sometimes interrelated. Is it simply deconditioning due to inactive lifestyle, chronotropic or inotropic insufficiency? or could there indeed be ventilatory limitation to exercise? These are the questions facing the clinician with the increasing frequency of patients undergoing repair early in life and growing into adulthood. Understanding pulmonary functional outcomes and means of determining ventilatory limitation to exercise is essential to thoroughly address the problem. This article reviews pulmonary function in patients with congenital heart disease and then describes a newer technique that should be applied to determine ventilatory limitation to exercise.     

Single Dose of Tiotropium Improves the 6-Minute Walk Distance in Chronic Obstructive Pulmonary Disease

The aim of this study was to evaluate the effect of a single dose of tiotropium on the exercise capacity of stable chronic obstructive pulmonary disease (COPD) patients. The study was a randomized, placebo-controlled, double-blind, cross-over study. Forty-four stable COPD patients with moderate to severe airway obstruction were selected according to the GOLD criteria. The regular anticholinergic therapies of the patients were interrupted one week before the test. In the morning hours of the first day, half the group was given one capsule (18 mcg) of tiotropium and the other half was given placebo as inhalation using the HandiHaler device. Before and 120 min after the medication, the 6-min walk test was performed. Oxygen saturation, modified Borg dyspnea ratings, blood pressure, and heart rate were recorded before and after the test. The same procedure was repeated at the same time on the third day but this time the patients were given placebo if they used tiotropium on the first day and vice versa. Before using tiotropium or placebo there was no difference between 6-min walk distances. The 6-min walk distance after the use of tiotropium (429.3 +/- 70.6 m) was significantly longer than that after the use of placebo (414.7 +/- 74.6 m). The changes in Borg dyspnea ratings and arterial oxygen saturation values with tiotropium and placebo use were not significant. We conclude that exercise capacity might be improved by using a single-dose tiotropium inhalation in moderate to severe COPD patients.     

Effect of Metabolic Control on Autonomic Function in Obese Patients with Newly Diagnosed Type 2 Diabetes

To evaluate the effect of diet therapy and physical exercise on autonomic nervous function in newly diagnosed Type 2 diabetes, we followed 83 middle-aged obese patients (48 men, 35 women) for a 15-month period. After a 3-month basic education programme the patients were randomized to one of two groups for comparison of standard treatment given by community health centres (conventionally treated group) and intensive dietary and exercise education (intervention group). Autonomic function was assessed by heart rate variability during deep breathing (expiration/inspiration ratio, E/I), and by systolic blood pressure response to standing up. The intensively treated women (n = 18) had the best blood glucose throughout the study, and this was the only group to show an improvement in E/I ratio (1.19 ± 0.03 vs 1.30 ± 0.05, mean ± SEM, p < 0.05). None of the groups showed any significant change in systolic blood pressure response to standing up. For further analyses, the original groups were combined and thereafter divided into those with declining fasting blood glucose during the intervention phase (n = 39) and into those with no change or increase in blood glucose level (n = 44). The group with improving blood glucose level showed an increase in E/I ratio (1.22 ± 0.02 vs 1.28 ± 0.03, p < 0.01) while in the other group E/I ratio remained unchanged (1.21 ± 0.02 vs 1.20 ± 0.02). The difference in E/I ratio between these two groups was significant at 15 months (p < 0.05). In conclusion, good blood glucose control is associated with an improvement in E/I ratio in patients with newly diagnosed Type 2 diabetes suggesting that cardiac autonomic dysfunction is at least in part functional in nature.     

Improved Physical Function After Cardiac Contractility Modulation Therapy in 10 Patients With Chronic Heart Failure

BackgroundA new generation of therapeutic devices has expanded the options for managing advanced heart failure. We examined the outcomes of cardiac contractility therapy in a series of 10 patients with chronic heart failure.MethodsTen patients with chronic heart failure were nonrandomly selected to receive cardiac contractility modulation therapy. Hemodynamics, left ventricular ejection fraction, functional capacity, and clinical outcomes were evaluated at baseline and after 6 months of therapy.ResultsEight male and 2 female patients (mean [SD] age, 63.4 [9.4] years) received cardiac contractility modulation therapy. Between baseline and 6-month follow-up, mean (SD) left ventricular ejection fraction improved from 27.1% (4.18%) to 35.1% (9.89%), New York Heart Association class declined from 3.9 (0.32) to 2.44 (0.52), and 6-minute walk test distance increased from 159.2 (93.79) m to 212.4 (87.24) m. Furthermore, the mean (SD) number of hospital admissions within the 6 months before cardiac contractility modulation therapy was 2.4 (2.27) compared with 1 (1.52) during the 6 months after therapy.ConclusionCardiac contractility modulation therapy improved physical functioning and reduced hospital admissions in these patients.     

Serum Uric Acid to Creatinine Ratio in Patients with Chronic Obstructive Pulmonary Disease

Serum uric acid (UA), the final product of purine degradation, has been shown to be increased in the hypoxic state. We assessed whether the presence of higher values of serum UA and serum UA to creatinine ratio is associated with clinical or functional characteristics in patients with chronic obstructive pulmonary disease (COPD). Fifty-nine consecutive stable patients with COPD, without comorbid conditions, were included. Clinical and functional characteristics were compared between patients with levels below and above the median values of serum UA and serum UA to creatinine ratio. Patients with serum UA levels above the median value differed significantly from the group with levels below this value only in FVC (p = 0.04), and serum UA did not correlate significantly with the parameters analyzed. Patients with the serum UA to creatinine ratio above the median value had lower FVC (63 ± 18 vs. 73 ± 15 percentage of predicted, p = 0.028), lower FEV₁ (43 ± 19 vs. 55 ± 18 percentage of predicted, p = 0.019), and a higher level of dyspnea (MRC scale, 1.5 ± 1.1 vs. 0.8 ± 1.0, p = 0.011). The serum UA to creatinine ratio correlated with FVC (r = −0.27), with FEV₁ (r = −0.31), and with dyspnea (r = 0.29). In view of these results, we consider that the serum UA to creatinine ratio warrants evaluation as an additional parameter for predicting outcome in COPD.