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PubMed2001

[The six minute walking test elicits lung hyperinflation in patients with severe chronic obstructive lung disease].

BACKGROUND: Exercise tolerance in patients with COPD is highly variable and poorly related to airways obstruction assessed by FEV1. These patients develop dynamic hyperinflation (DH) during an incremental exercise test which can be evaluated through a reduction in inspiratory capacity (IC). AIM: To evaluate: a) if the six minute walking test (6 MWD) induce DH reducing IC, b) if the reduction in IC is related to tidal expiratory flow limitation at rest (FL). SUBJECTS AND METHODS: Thirty eight stable COPD patients (28 FL and ten non FL during resting breathing, determined by the negative pressure technique). Inspiratory capacity was measured before and immediately after the 6 MWD test. Dyspnea, SpO2 and heart rate were measured before and after the test. RESULTS: Inspiratory capacity was lower in FL patients as compared to patients without FL (p < 0.005). Although no differences were found between groups in 6 MWD, dyspnea and HR, a significant reduction in IC after the walking test was observed only in FL patients (p < 0.0001). In addition, SpO2 fell significantly (p < 0.0001) after walking in the same group. CONCLUSIONS: Our results demonstrate that a moderate exercise such as the walking test induces DH and hypoxemia in patients with COPD and FL and stresses the importance of assessing DH by measuring IC in these patients.

Aged↗

PubMedDate not supplied

A controlled trial of the effects of leg training on breathing pattern and dynamic hyperinflation in severe COPD.

The effects of training on dynamic hyperinflation in stable chronic obstructive pulmonary disease (COPD) were investigated by using a controlled study of 28 subjects with FEV(1) = 42.5 (8.3 SD)%pred and 20 matched controls [FEV(1) = 44.9 (10.4)%pred]. Training consisted of spending 45 min/day, 4 days/week on a cycle-ergometer for six weeks. Maximal inspiratory and expiratory pressures (MIP and MEP), lung volumes, and two constant-work-rate (CWR) exercise tests (low- and high-intensity) were performed. Significant (p < 0.0l) improvements in the training group were observed in MIP [+8 (12) cmH(2)O], MEP [+18 (20) cmH(2)O], and endurance to high-intensity CWR [+7(5) min], and there were significant decreases in respiratory rate and end-expiratory lung volume (EELV) during both exercise tests. At 5 min, EELV decreased 0.1(0.08) L and 0.31(0.13) L and at end of exercise, EELV decreased by 0.09(0.07) L and 0.15(0.11) L respectively, for the moderate- and high-intensity tests. Dyspnea also decreased significantly at both exercise intensities. No changes were observed in the control group. Increased endurance showed independent significant (p < 0.05) correlation with changes in EELV, leg fatigue, and MEP. EELV changes showed a significant negative correlation with resting inspiratory capacity. We conclude that exercise training has beneficial effects on respiratory pattern and dynamic hyperinflation that may partially explain the reduction in dyspnea and the improvement in exercise tolerance.

Aged↗

PubMed2002

Peripheral muscle strength in young males with cystic fibrosis.

BACKGROUND: In children with cystic fibrosis there is a decrease in peak work capacity and oxygen consumption on maximal exercise testing when compared to controls. Previous studies have shown that peripheral muscle force is decreased in children with cystic fibrosis even in those with minimal changes in lung function. However, no studies have examined peripheral muscle strength using isokinetic dynamometry which permits measurement of muscle strength throughout range and is considered the gold standard in orthopaedics and sports medicine. METHODS: Isokinetic muscle strength was measured in the knee flexors and extensors and shoulder flexors and extensors at two speeds of movement in children with cystic fibrosis and matched controls. Activity levels in both groups were calculated. RESULTS: Thirteen subjects and 13 age and height matched controls were assessed. Average peak torque was calculated and expressed in terms of body weight. There was a significant difference in peak torque/body weight in children with cystic fibrosis when compared to controls. FEV1 was significantly correlated with knee muscle strength and shoulder flexion at 90 degrees /s in subjects with CF. CONCLUSION: Children with CF had lower muscle strength than control subjects. Airflow limitation was associated with decreased muscle strength. The relationship between muscle strength and exercise tolerance requires investigation.

Adolescent↗

PubMed2004

Physiological responses during a submaximal cycle test in chronic fatigue syndrome.

INTRODUCTION/PURPOSE: Numerous studies have assessed physical function in individuals suffering from chronic fatigue syndrome (CFS) but neglected to match control subjects according to current activity levels, consequently casting doubt on reported results. The purpose of this study was to include current activity levels as one criterion for matching CFS subjects with healthy control subjects in order to more accurately assess physical function in these subjects. METHODS: Thirty-one healthy control subjects were matched to CFS subjects according to age, gender, body mass, height, and current activity levels. Physiological function was assessed weekly over a 4-wk period using a submaximal cycle test. RESULTS: Comparison of absolute physiological results recorded at the end of each incremental work level of the exercise test showed that ratings of perceived effort (RPE) was the only variable that was significantly different between the two groups. Scores for RPE were significantly higher in CFS subjects for each incremental work level assessed. Conversely, results recorded on completion of the exercise test showed that the control group was capable of a greater power output than the CFS group as reflected by significantly higher scores for watts per kilogram (P < 0.0005), net lactate production (P = 0.003), oxygen uptake (mL x kg(-1) x min(-1); P < 0.0005), respiratory exchange ratio (P = 0.021), and HR values as a percentage of age predicted HR(max) (P = 0.001). End-point RPE scores were again significantly higher in the CFS group (P < 0.0005). CONCLUSION: It is proposed that the reduced exercise tolerance in CFS is due to impairment in the mechanisms that constitute effort sense and/or to avoidance behaviors that result in a reluctance by these subject to exercise to full capacity.

Adult↗

PubMed1993

Does cold air affect exercise capacity and dyspnea in stable chronic obstructive pulmonary disease?

Cold air may worsen asthmatic bronchoconstriction but can lessen breathlessness in normal individuals. Patients with COPD sometimes report improvement in their dyspnea in cold weather. We examined the effect of breathing cold air on exercise tolerance and the perception of breathlessness in 19 patients with stable COPD (age [+/- SD], 63 +/- 6 years; FEV1, 0.99 +/- 0.28 L) in a randomized open study. Patients exercised on a cycle ergometer breathing either room or cold air (-13 degrees C), breathlessness being assessed by Borg scaling. Peak exercise performance improved when breathing cold air (mean +/- SE), 46 +/- 6 W compared with 37 +/- 7 W (p < 0.05) while end-exercise breathlessness fell from 4.6 +/- 0.4 compared with 4.1 +/- 0.5 (p < 0.05) when breathing cold air. End-exercise ETCO2 was higher breathing cold air (6.1 +/- 0.3 kPa compared with 5.5 +/- 0.3 kPa) (p < 0.005). There was no difference in breathlessness at equivalent levels of ventilation. Cold air reduces breathlessness in COPD, probably by inducing relative hypoventilation.

Aged↗

PubMed1999

[Efficacy of pulmonary rehabilitation].

Pulmonary rehabilitation is comprehensive and multidimensional care for patients with COPD and their families. The aim of pulmonary rehabilitation is for patients to achieve and maintain the individual's maximum level of independence and functioning in the communities. Recent investigation of well-designed studies confirmed the efficacy of lower extremity training, upper extremity training, and ventilatory muscle training in some selected patients. Patient education is a essential component. Pulmonary rehabilitation improves exercise tolerance, the symptoms of dyspnea and health-related QOL, and reduce the frequency and period of hospitalizations. Pulmonary rehabilitation programs include assessment and education of patient, exercise training, and chest physical therapy techniques. In our follow-up study in 100 patients with chronic pulmonary emphysema who participated in pulmonary rehabilitation programs, groups that continued exercise more than 30 minutes a day at home, had tendency to escape from progression of dyspnea after 19 months (mean).

Exercise Therapy↗

PubMed1996

[Acetylsalicylic acid antagonism vs ACE inhibitor in congestive heart failure as shown by a diminished respiratory and exercise capacity].

Our hypothesis is that regulation of the lung vessel tone and microvascular permeability may be disrupted in chronic heart failure (CHF) and angiotensin converting enzyme (ACE) inhibition may contribute to their readjustment. This hypothesis is based on the fact that KII-ACE, the same enzyme that converts angiotensin I and inactivates bradykinin, is highly concentrated in the luminal surface of the lung vessels and its blockade in CHF may reduce their exposure to an excess of angiotensin II and augment the action of prostaglandins and nitric oxide (NO) deriving from local kinin hyperconcentration. We probed whether ACE-inhibitors influence the pulmonary function; this is peculiar of CHF; they act as KII- or ACE-blockers. Aspirin was utilized as a prostaglandin synthesis inhibitor. We investigated 16 CHF patients and 16 age- and sex-matched normal volunteers or mild untreated hypertensives. All were non-smokers, not taking ACE-inhibitors, aspirin or other cyclooxygenase inhibitors. Pulmonary function tests, exercise testing with respiratory gases and echocardiography were performed in the run-in and repeated at the end of placebo, enalapril (10 mg t.i.d.), enalapril plus aspirin (325 mg/day) and aspirin given in random order and double-blind fashion for 15 days each. Enalapril, as compared to placebo, caused an increase in mean voluntary ventilation (MVV) and alveolar-capillary diffusing capacity for carbon monoxide (DLCO) in CHF, that were counteracted by the addition of aspirin. Aspirin alone was not effective. Enalapril and aspirin were ineffective on the pulmonary function of controls. As to the functional capacity, enalapril increased exercise tolerance time, oxygen consumption (VO2p), minute ventilation (VEp) tidal volume (VTp) and reduced the ratio of volume of dead space gas (VDp) to VTp (VD/VTp), at peak exercise in CHF patients. These effects all were inhibited by the combination of aspirin and were not observed in controls. In CHF VO2p changes from placebo correlated with those in DLCO (r = 0.80, p < 0.0001) and not with those in ejection fraction. This correlation was abolished by aspirin and was not seen in controls. Variations in VD/VTp in CHF patients while on enalapril were related to those in DLCO (r = -0.69, p = 0.003). In CHF the ventilatory equivalent for carbon dioxide production per minute at 1 liter was diminished with enalapril and not in combination with aspirin. Derangements related to CHF are the substrate for benefits of ACE-inhibition on pulmonary function and exercise capacity. Pulmonary diffusion limitation is an important mediator of exercise impairment and its improvement with enalapril goes in parallel with VD/VT, MVV, VT, VE to VCO2 relationship and not with ejection fraction. These patterns reflect changes occurring within the lung that are not related to left ventricular function. The counteracting influence of aspirin on these affects bespeaks a substantial participation of prostaglandins that might readjust capillary permeability and lung interstitial fluid content or alveolar capillary membrane diffusing capacity.

Aged↗

PubMed1997

[Effects of bilateral lung volume reduction surgery in a patient with severe pulmonary emphysema].

A 61-year-old man suffering from severe pulmonary emphysema underwent lung volume reduction surgery on both upper lobes. By one year after surgery functional residual capacity had decreased by 2.5 L and FEV1 had increased by a factor of 2.4. Diaphragm excursion, as assessed by dynamic magnetic resonance imaging, had increased and ventilation and pulmonary gas exchange had improved. Performance on a 6-minute-walk test and exercise tolerance measured on a bicycle ergometer improved, and both peak VE and VO2 increased. Before surgery, pulmonary artery pressure Ppa and pulmonary capillary wedge pressure Pewp during exercise were abnormally high, but 6 months after the operation the increases in Ppa and Pcwp during exercise were markedly reduced.

Chronic Disease↗

PubMed2001

Metabolic effects and safety profile of nebivolol.

Nebivolol, compared with classical beta-blockers, exerts a high selectivity for beta-adrenergic receptors and also reduces peripheral vascular resistance by modulating nitric oxide (NO) release. This dual mechanism of action leads to effective control of blood pressure at a low degree of beta-blockade and explains the lack of any interference with lipid metabolism. For the same reason, the tolerability profile of nebivolol is highly favorable compared with the classical beta-blockers, with less fatigue and dyspnea in hypertensive subjects, and with an improvement of functional capacity and exercise tolerance in patients with left ventricular dysfunction. Furthermore, contrary to atenolol and propranolol, nebivolol does not diminish specific airway conductance. Compared with other first-line antihypertensive agents, nebivolol was shown to be better tolerated than nifedipine and enalapril, and to have a positive effect on general wellbeing. Among the currently available antihypertensive drugs, nebivolol therefore appears to have a most alteractive safety and tolerability profile, which can be attributed to its NO-mediated effects allowing effective control of hypertension at a lower degree of beta-blockade than with first-generation beta-blockers.

Adrenergic beta-Antagonists↗

PubMed2005

Accuracy of pulmonary function tests in predicted exercise capacity in COPD patients.

PURPOSE: The purpose of this study was to examine exercise tolerance in patients with COPD from measurements of resting pulmonary function parameters. METHODS: A total of 57 COPD patients were administered the pulmonary function test (PFT) and cardiopulmonary exercise test. The results were analyzed and essentially linear relationships emerged when each subject's VO2 peak was plotted against his individual PFT parameters. Those significant contributors were then introduced in a stepwise multiple regression analysis to determine the best predictor of the VO2 peak. RESULTS: Stepwise multiple regressions in variables revealed that peak oxygen consumption (VO2 peak) was predicted best by the following equation: VO2 peak=(maximum voluntary ventilation x 0.024)+(forced mid-expiratory flow x 0.47)+(body surface area x 0.988)-0.913 (r=0.90; r2=0.81 SE=0.29 L/min). CONCLUSION: We conclude that exercise capacity was predicted from measurements of resting pulmonary function parameters with excellent accuracy in the COPD patient.

Aged↗

PubMed2005

Surgical therapy for chronic obstructive pulmonary disease.

Many patients with severe chronic obstructive pulmonary disease (COPD) experience incapacitating breathlessness and exercise limitation. Multiple surgical techniques have been utilized to achieve resection of giant, localized bullae with documented short-term benefit in pulmonary function and dyspnea in highly selected patients. The poorest long-term outcome has been noted in those with greater degrees of emphysema in the remaining lung, greater underlying chronic bronchitis, and a bulla occupying less than one third of the hemithorax, particularly if compressed normal lung is not evident. Lung volume reduction surgery (LVRS) in the absence of giant bullae has become more widely accepted in selected patients. Bilateral LVRS procedures appear to result in greater short-term improvement than unilateral LVRS, whereas physiological benefits appear similar with video-assisted thoracoscopy (VATS) or median sternotomy (MS) techniques. Improvement in dyspnea and health status after LVRS has been documented and appears to be better preserved over longer-term follow-up than physiological improvement. Clear direction has been provided in identifying optimal candidates for bilateral LVRS; patients with a postbronchodilator forced expiratory volume in 1 second (FEV (1)) < or = 20% predicted and a diffusing capacity for carbon monoxide (DL (CO)) < or = 20% predicted or homogeneous emphysema exhibit a much higher mortality with LVRS than with medical management. Patients with upper-lobe predominant emphysema and a low postrehabilitation exercise tolerance exhibited a decreased risk of mortality after LVRS. Patients with non-upper lobe predominant emphysema on high-resolution computed tomography (HRCT) and a high postrehabilitation exercise capacity exhibit an increased risk of death after LVRS. Patients with upper lobe predominant emphysema and a high postrehabilitation exercise capacity or patients with non-upper lobe predominant emphysema and a low postrehabilitation exercise capacity do not have a survival advantage or disadvantage, whereas those with upper lobe predominant emphysema treated surgically are more likely to improve their exercise capacity after surgery. Lung transplantation is an option for a more limited number of patients. Consistent short-term spirometric improvement after both single- and double-lung transplant has been documented. Long-term results of lung transplantation are limited by significant complications that impair survival; an approximately 80% 1-year, 50% 5-year, and 35% 10-year survival has been reported. Bronchiolitis obliterans is the most important long-term complication of lung transplantation resulting in decreased pulmonary function. In general, a COPD patient can be considered an appropriate candidate for transplantation when the FEV (1) is below 25% predicted and/or the paCO (2) is > or = 55 mm Hg.

Disease Progression↗

PubMed1996

Impaired cardiopulmonary exercise capacity in patients with hyperthyroidism.

STUDY OBJECTIVE: Hyperthyroidism (H) has been implicated as a primary cause of decreased exercise tolerance. To our knowledge, analysis of respiratory gas exchange, an efficient noninvasive method in evaluating cardiopulmonary capacity, has not been performed in patients with H. PATIENTS: Using cardiopulmonary exercise testing, 12 consecutive women with Graves' H were examined and controlled in euthyroidism (E). Eighteen women with E, in whom cardiac catheterization had ruled out heart disease, served as control subjects (C). MEASUREMENTS: The ventilatory anaerobic threshold was determined by means of the V-slope method. Ergometry was performed with patients in a semisupine position using a continuous ramp protocol of 20 W/min. Echocardiography at rest was performed in all patients. RESULTS: In patients with H, heart rate at rest was higher than in patients with E (p < 0.05) and showed a markedly lower increase between rest and anaerobic threshold compared with E patients (p = 0.007) and C (p = 0.009). Work rate was reduced (H, 50% vs E, 70%; p = 0.038). In H patients, the anaerobic threshold occurred at 59.6% of maximal oxygen uptake and 72% in E patients, respectively (p = 0.024). In H patients, the linear regression of the heart rate to oxygen uptake ratio showed a reduced slope in comparison with E patients (p = 0.001) and C (p = 0.004). In patients with H, a reduced tidal volume (p = 0.021) and an increased respiratory rate (p = 0.003) in comparison to patients with E were demonstrated. Echocardiographically, H patients had an increased ejection fraction (p = 0.008) and a higher cardiac index (p = 0.008) in comparison with E patients. CONCLUSIONS: Analysis of respiratory gas exchange showed marked alterations of cardiopulmonary exercise capacity in H patients, which are reversible in E patients. The impaired chronotropic response during exercise might be the primary limiting factor of reduced work capacity in patients with H.

Adult↗

PubMed2006

Exercise performance improves in patients with COPD due to respiratory muscle endurance training.

BACKGROUND: Impaired exercise tolerance is frequently observed in patients with COPD. Respiratory muscle endurance training (RMET) by means of normocapnic hyperpnea can be used to improve respiratory muscle function and probably exercise capacity. RMET is not applied on a large scale because complicated equipment is needed to maintain carbon dioxide homeostasis during hyperpnea, which can also be done by enlarging the dead space of the ventilatory system by breathing through a tube. Therefore, tube breathing might be a new, inexpensive method for home-based RMET. The aim of this study was to assess whether home-based RMET by means of tube breathing improves endurance exercise performance in patients with COPD. METHODS: We randomized 36 patients with moderate-to-severe COPD to RMET by paced tube breathing (n = 18) or sham training (control, n = 18). Both groups trained twice daily for 15 min, 7 days per week, for 5 weeks. RESULTS: Patients receiving RMET showed significant improvements in endurance exercise capacity (constant-load exercise on cycle ergometry; 18 min vs 28 min, p < 0.001), in perception of dyspnea (Borg score; 8.4 vs 5.4, p < 0.001), and respiratory muscle endurance capacity (sustainable inspiratory pressure; 25 cm H(2)O vs 31 cm H(2)O, p = 0.005). Quality of life (chronic respiratory disease questionnaire) also improved (78.7 to 86.6, p = 0.001). The control group showed no significant changes. CONCLUSION: Home-based RMET by means of tube breathing leads to a significant improvement of endurance exercise capacity, a reduction in perception of dyspnea, and an improvement in quality of life in patients with moderate-to-severe COPD.

Aged↗

PubMed1996

Low efficiency of oxygen utilization during exercise in hyperthyroidism.

STUDY OBJECTIVE: The mechanism of exercise intolerance in hyperthyroidism has not been fully elucidated. This study was undertaken to determine if hyperthyroidism reduced the efficiency of sub-maximal exercise. STUDY DESIGN: We measured cardiorespiratory variables up to the anaerobic threshold (AT) during ramp-loading cycle ergometry in 12 patients (New York Heart Association functional class II or III). Studies were performed in the hyperthyroid state and repeated in the euthyroid state after 10 months of medical treatment. In 10-W steps from rest to the AT, we measured oxygen uptake (VO2) as a measure of total body work rate, and pressure rate product (PRP) as a measure of cardiac work rate. Loading watts at AT divided by the increment of Vo2 from rest to the AT (delta Watt/delta VO2) was calculated as an index of work efficiency (where delta means the increment of each value from rest to the AT). RESULTS: VO2 and PRP at the AT were not significantly different between hyperthyroid and euthyroid states (VO2, 16.6 +/- 3.0 vs 17.5 +/- 2.3 mL/min/kg; PRP, 229 +/- 41 vs 218 +/- 28 x 10(2) mm Hg/min). However, loading watts at the AT were significantly lower in the hyperthyroid than the euthyroid state (28 +/- 22 vs 60 +/- 14 W: p < 0.01). VO2 and PRP while hyperthyroid were significantly higher than when euthyroid at every 10-W step during ramp-loading exercise. Furthermore, delta Watt/delta VO2 was significantly lower in hyperthyroid than euthyroid states (p < 0.001). There was a significant inverse correlation-ship between triiodothyronine and delta Watt/delta Vo2 (r = -0.654, p < 0.001). CONCLUSION: Hyperthyroidism causes low work efficiency, which may limit exercise tolerance.

Adult↗

PubMed2005

Strength training for patients with chronic heart failure.

Chronic (congestive) heart failure (CHF) is a disabling disease where patients suffer from dyspnoea and exercise intolerance. Peripheral skeletal muscle disorders play a major role in the pathogenesis of these symptoms and also in the progression of the disease. Besides cardiovascular endurance training, strength training should be an important component of cardiac rehabilitation programs in CHF because of its ability to efficiently improve muscle function and muscle mass. Safety of this type of training, while long-time questioned, has been established. Training recommendations for strength training should be based on current research. The positive training effects induced by strength training improve the patients' functional capacity and exercise tolerance and thereby also their quality of life and its widespread use should be promoted.

Exercise Therapy↗

PubMed2001

Total cavopulmonary conversion and maze procedure for patients with failure of the Fontan operation.

OBJECTIVES: Hemodynamic abnormalities and refractory atrial arrhythmias in patients late after the Fontan operation result in significant morbidity and mortality. We review our experience with conversion to total cavopulmonary artery connections and arrhythmia surgery. METHODS: Between 1994 and 2001, 40 patients underwent Fontan conversion and arrhythmia surgery. Significant hemodynamic lesions such as aortic aneurysm (n = 1), atrioventricular valve insufficiency (n = 8), and pulmonary arterioplasty (n = 9) were repaired concomitantly. Thirty-four patients were in New York Heart Association class III or IV. Mean age at the original Fontan operation was 7.5 +/- 6.5 years and mean age at Fontan conversion was 18.7 +/- 9.0 years. Arrhythmia surgery has evolved from isthmus cryoablation in 10 patients to right-sided maze in 16 patients for atrial reentry tachycardia. The maze-Cox III operation was used for 14 patients with atrial fibrillation. Atrial (n = 33) and dual-chamber (n = 5) pacemakers were placed. RESULTS: There has been no early mortality. Chest tubes were removed on postoperative day 9.0 +/- 6.0. Hospital stay was 11.8 +/- 6.6 days. Three patients required cardiac transplantation at 8 days, 9 months, and 33 months postoperatively. There was 1 death 2 years postoperatively from acute myocardial infarction. For the entire series, arrhythmia recurrence is 12.5%, with only 10% of patients receiving long-term antiarrhythmic medications; these patients were among the first 8 patients in our series. Most patients are in New York Heart Association class I or II. Bruce protocol in 12 patients showed increased tolerance (P <.05). CONCLUSIONS: Fontan conversion to total cavopulmonary connection with concomitant arrhythmia surgery is excellent therapy for patients whose Fontan repair has failed. Fontan conversion is safe, improves New York Heart Association class, improves exercise tolerance, and has a low incidence of recurrent arrhythmias.

Adolescent↗

PubMed2006

Effect of L-carnitine on the physical fitness of thalassemic patients.

Poor physical fitness is a common problem among thalassemic patients. L-Carnitine plays an essential role in fatty acid beta-oxidation, a process especially important in the organs that preferentially use fatty acid as a source of energy such as the myocardium and the skeletal muscles. The main objective of this study is to assess the effect of the administration of oral L-carnitine on exercise tolerance and physical fitness in patients with thalassemia major. Thirty patients followed up at the New Cairo University Children Hospital were included in this study. Clinical, laboratory, and cardiopulmonary exercise testing were performed before and after 6 months of oral L-carnitine therapy (50 mg/kg/day). The oxygen consumption, cardiac output, and oxygen pulse at maximal exercise significantly increased after L-carnitine therapy (p<0.001, p=0.002 and p<0.001, respectively). However, there was no significant change in minute ventilation and ventilatory equivalent of carbon dioxide (p=0.07 and p=0.06, respectively). A weak but positive correlation between the age of the patients and the degree of improvement in exercise parameters was noted. There was also significant increase in the blood transfusion intervals after L-carnitine administration (p=0.008). However, there was no significant change in hemoglobin concentration (p=0.4). L-Carnitine seems to be a safe and effective adjunctive therapeutic approach in thalassemic patients. It improves their cardiac performance and physical fitness. The younger the patients are, the higher is the degree of improvement in their exercise parameters.

Administration, Oral↗

PubMedDate not supplied

Airflow limitation and breathing strategy in congestive heart failure patients during exercise.

BACKGROUND: Congestive heart failure (CHF) patients experience dyspnea on exertion and therefore have decreased exercise tolerance. OBJECTIVE: This study explores the hypothesis that stable New York Heart Association (NYHA) class III CHF patients without a history of pulmonary disease exhibit airflow limitation with increasing exercise. METHODS: We characterized flow limitations and breathing reserves at baseline, during exercise before anaerobic threshold (pre-AT), and after anaerobic threshold (post-AT) in CHF patients and normal subjects. Data were collected in the form of maximal flow volume loops and subsequent tidal flow volume loops at baseline and during exercise. Expiratory flow limitation was expressed as percent of tidal volume that corresponded with overlap of the tidal flow volume loops and maximal flow volume loops during expiration. The area directly between the maximum flow volume loops and the tidal flow volume loops during the expiratory phase is expressed as expiratory flow volume reserve (EFVR). RESULTS: CHF patients experienced expiratory flow limitation during exercise (pre-AT and post-AT) that was significantly increased compared to baseline and to normal subjects at similar exercise levels (CHF, baseline 8.5 +/- 7, pre-AT 37 +/- 10, post-AT 38 +/- 8%, n = 9, p < 0.05). Both CHF patients and normal subjects increased EFVR during exercise, but only the normal subjects increased EFVR to a significantly different value at post-AT exercise levels (normal subjects, 9.5 +/- 2, 11 +/- 2, 32 +/- 4%, n = 7, p < 0.05). Both CHF patients and normal subjects increased end inspiratory lung volume (EILV) during exercise, but only the normal subjects significantly increased EILV at post-AT exercise levels (normal subjects, 49 +/- 4, 55 +/- 5, 76 +/- 4%, p < 0.05). Inspiratory capacity (IC)/forced vital capacity (FVC) ratios were increased in CHF patients compared to normal subjects. However, IC/FVC values did not change during exercise in either group. CONCLUSIONS: CHF patients cannot utilize their full respiratory capacity during exercise secondary to expiratory flow limitation and an inability to increase EILV and EFVR.

Exercise↗

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