SEARCH · PubMed Health

Results for “exercise capacity”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 541 records · Page 30Linked to original sources

PubMed1997

Exercise capacity in young and old mares.

OBJECTIVE: To test the hypothesis that, compared with unfit young horses, unfit older horses have lower aerobic capacity and reduction in other indices of exercise capacity. ANIMALS: 6 young (mean +/- SEM, 5.3 +/- 0.8 years and 445 +/- 13 kg) and 6 aged (22.0 +/- 0.4 years and 473 +/- 18 kg) healthy Standardbred and Thoroughbred mares. PROCEDURES: The mares, accustomed to running on a treadmill, were tested by use of an incremental exercise test. None of the mares had received exercise training for at least 4 months prior to the study. During testing, mares ran up a fixed 6% grade, starting at a speed of 4 m/s, with 1 m/s increase every 60 seconds (omitting 5 m/s) until they reached fatigue. Maximal oxygen uptake (VO2max) was measured by use of an open-flow calorimeter. Venous blood samples (10 ml) were collected during the last 10 seconds of each step and were used to measure blood lactate concentration and PCV. Calculated performance indices included velocity at VO2max, maximal velocity, and velocity at lactate concentration of 4 mmol/L; work rate (watts) at those velocities also was determined. RESULTS: There were differences (P < 0.05) between old and young mares for maximal run velocity attained during the test (8.7 +/- 0.5 versus 10.8 +/- 0.5 m/s, respectively), VO2max (89.4 +/- 4.3 versus 117.3 +/- 9.5 ml/kg of body weight/min, respectively), and velocity at VO2max (8.0 +/- 0.4 versus 9.8 +/- 0.7 m/s, respectively). Also, velocity required to reach blood lactate concentration of 4 mmol/L was lower (P < 0.05) in old (7.5 +/- 0.4 m/s), compared with young (10.2 +/- 0.7 m/s), mares. CONCLUSION: Older mares have substantially (-24%) lower maximal aerobic capacity than do young mares. CLINICAL RELEVANCE: Many horses participate in athletic activities into their late teens and some do so beyond the age of 20 years; thus, the need exists to explore ways to adjust training programs for older horses.

Aging↗

PubMed2004

Left ventricular chamber stiffness at rest as a determinant of exercise capacity in heart failure subjects with decreased ejection fraction.

Impaired exercise tolerance, determined by peak oxygen consumption (VO2 peak), is predictive of mortality and the necessity for cardiac transplantation in patients with chronic heart failure (HF). However, the role of left ventricular (LV) diastolic function at rest, reflected by chamber stiffness assessed echocardiographically, as a determinant of exercise tolerance is unknown. Increased LV chamber stiffness and limitation of VO2 peak are known correlates of HF. Yet, the relationship between chamber stiffness and VO2 peak in subjects with HF has not been fully determined. Forty-one patients with HF New York Heart Association [(NYHA) class 2.4 +/- 0.8, mean +/- SD] had echocardiographic studies and VO2 peak measurements. Transmitral Doppler E waves were analyzed using a previously validated method to determine k, the LV chamber stiffness parameter. Multiple linear regression analysis of VO(2 peak) variance indicated that LV chamber stiffness k (r2 = 0.55) and NYHA classification (r2 = 0.43) were its best independent predictors and when taken together account for 59% of the variability in VO2 peak. We conclude that diastolic function at rest, as manifested by chamber stiffness, is a major determinant of maximal exercise capacity in HF.

Blood Pressure↗

PubMed2004

Effects of adrenomedullin inhalation on hemodynamics and exercise capacity in patients with idiopathic pulmonary arterial hypertension.

BACKGROUND: Adrenomedullin (AM) is a potent pulmonary vasodilator peptide. However, whether intratracheal delivery of aerosolized AM has beneficial effects in patients with idiopathic pulmonary arterial hypertension remains unknown. Accordingly, we investigated the effects of AM inhalation on pulmonary hemodynamics and exercise capacity in patients with idiopathic pulmonary arterial hypertension. METHODS AND RESULTS: Acute hemodynamic responses to inhalation of aerosolized AM (10 microg/kg body wt) were examined in 11 patients with idiopathic pulmonary arterial hypertension during cardiac catheterization. Cardiopulmonary exercise testing was performed immediately after inhalation of aerosolized AM or placebo. The work rate was increased by 15 W/min until the symptom-limited maximum, with breath-by-breath gas analysis. Inhalation of AM produced a 13% decrease in mean pulmonary arterial pressure (54+/-3 to 47+/-3 mm Hg, P<0.05) and a 22% decrease in pulmonary vascular resistance (12.6+/-1.5 to 9.8+/-1.3 Wood units, P<0.05). However, neither systemic arterial pressure nor heart rate was altered. Inhalation of AM significantly increased peak oxygen consumption during exercise (peak o(2), 14.6+/-0.6 to 15.7+/-0.6 mL. kg(-1). min(-1), P<0.05) and the ratio of change in oxygen uptake to that in work rate (Deltao(2)/DeltaW ratio, 6.3+/-0.4 to 7.0+/-0.5 mL. min(-1). W(-1), P<0.05). These parameters remained unchanged during placebo inhalation. CONCLUSIONS: Inhalation of AM may have beneficial effects on pulmonary hemodynamics and exercise capacity in patients with idiopathic pulmonary arterial hypertension.

Administration, Inhalation↗

PubMed2004

Effects of ghrelin administration on left ventricular function, exercise capacity, and muscle wasting in patients with chronic heart failure.

BACKGROUND: Ghrelin is a novel growth hormone-releasing peptide that also induces vasodilation, inhibits sympathetic nerve activity, and stimulates feeding through growth hormone-independent mechanisms. We investigated the effects of ghrelin on left ventricular (LV) function, exercise capacity, and muscle wasting in patients with chronic heart failure (CHF). METHODS AND RESULTS: Human synthetic ghrelin (2 microg/kg twice a day) was intravenously administered to 10 patients with CHF for 3 weeks. Echocardiography, cardiopulmonary exercise testing, dual x-ray absorptiometry, and blood sampling were performed before and after ghrelin therapy. A single administration of ghrelin elicited a marked increase in serum GH (25-fold). Three-week administration of ghrelin resulted in a significant decrease in plasma norepinephrine (1132+/-188 to 655+/-134 pg/mL; P<0.001). Ghrelin increased LV ejection fraction (27+/-2% to 31+/-2%; P<0.05) in association with an increase in LV mass and a decrease in LV end-systolic volume. Treatment with ghrelin increased peak workload and peak oxygen consumption during exercise. Ghrelin improved muscle wasting, as indicated by increases in muscle strength and lean body mass. These parameters remained unchanged in 8 patients with CHF who did not receive ghrelin therapy. CONCLUSIONS: These preliminary results suggest that repeated administration of ghrelin improves LV function, exercise capacity, and muscle wasting in patients with CHF.

Aged↗

PubMed2004

The effect of chest wall restriction on exercise capacity.

OBJECTIVE: Subjects with restrictive pulmonary disease exhibit a decreased exercise capacity compared to non-diseased subjects, as do subjects in certain workplace situations, for example when wearing bullet-proof vests. The purpose of this study was to examine the effects of varying degrees of chest wall restrictive loading on exercise performance. We have designed and validated a chest wall restrictor that mimics the elastic loading occurring in some disease states and some occupational situations. METHODOLOGY: In this study, 18 subjects performed five graded maximal cycling tests while wearing the device at four different inflation pressures (0, 20, 40, and 60 mmHg). RESULTS: Maximal values of oxygen uptake (VO2max), minute ventilation (VImax), tidal volume (VT at max) and breathing frequency (fB at max) were monitored, as was the time to maximal exercise (TTM). VO2, VI, VT, and fB were also measured at three submaximal loads. The results showed that VO2max, VImax, TTM, and VT at max were significantly decreased, while fB at max was maintained. At submaximal loads, the ventilatory parameters VT, and fB were altered with load, but VI and VO2 were not affected by load. CONCLUSIONS: These results indicate that the wearing of this device decreases variables associated with maximal exercise, and that the decreases are related to the degree of chest wall restriction. Furthermore, submaximal exercise ventilation was minimally altered, with an increase in fB and a decrease in VT associated with increasing restrictive loads. Submaximal oxygen uptake was not affected by breathing restriction.

Adult↗

PubMed2004

Relationship of serum cardiac markers following successful percutaneous coronary intervention and subsequent exercise capacity in patients with chronic stable angina: a pilot study.

We performed a pilot study to assess the significance of modest, asymptomatic, elevated serum cardiac markers--troponin T (TnT) and creatinine kinase-MB (CK-MB)--18-24 h following successful elective percutaneous coronary intervention (PCI) and to explore their relationship with changes in aerobic exercise capacity, as measured by peak oxygen consumption (VO2), 6 weeks following the procedure. Twenty-three patients with single-vessel disease and chronic angina performed an incremental cardiopulmonary exercise test before and 6 weeks after successful uncomplicated PCI. A venous blood sample was taken at rest before PCI and 18-24 h after the procedure. Successful PCI resulted in a trend towards an increased peak VO2 [21.62 +/- 0.64 (pre) vs. 23.03 +/- 0.75 ml/ kg/min (post), p = 0.07; mean +/- SEM]. There was a significant increase [median (IQR)] in TnT, from 0.00 (0.00) microg/l at baseline increasing to 0.02 (0.03) microg/l at 18-24 h, p = 0.002. CK-MB levels showed no significant difference. In the group of 15/23 (65%) patients with an elevation in serum TnT (>/=0.01 microg/l), 18-24 h after successful PCI, there was no significant increase in peak VO2 [23.31 +/- 0.96 (pre) vs. 23.89 +/- 1.09 ml/kg/min (post), p = 0.57]. In 8 (35%) patients with no rise in TnT at 18-24 h, a significant increase in peak VO2 was observed following successful PCI [23.10 +/- 0.91 (pre) vs. 25.09 +/- 0.75 ml/kg/min (post), p = 0.02]. Although 7 of these 8 patients increased their peak VO2, the absence of a TnT rise at 18-24 h was not significantly associated with an increase in peak VO2 following successful PCI (p = 0.18). To confirm these interesting initial results and investigate the relationship of serum cardiac markers following successful PCI and subsequent exercise capacity, further studies are required.

Adult↗

PubMed2006

Plasma brain natriuretic peptide levels, right ventricular volume overload and exercise capacity in adolescents after surgical repair of tetralogy of Fallot.

BACKGROUND: Right ventricular (RV) volume overload secondary to pulmonary regurgitation contributes to long-term morbidities in patients after tetralogy of Fallot (TOF) repair. We tested the hypothesis that plasma brain natriuretic peptide (BNP) levels relate to RV volume overload, pulmonary regurgitation, and exercise capacity in adolescents after TOF repair. METHODS: We assessed the RV function echocardiographically and plasma BNP levels in 32 postoperative TOF patients aged 14.7+/-3.1 years and 20 age-matched controls. Eighteen patients further underwent cardiovascular magnetic resonance imaging and 26 had exercise testing. RESULTS: Compared with controls, patients had significantly higher BNP levels (p=0.027), greater indexed RV end-diastolic dimension (p<0.001), increased RV myocardial performance index (p=0.005), and reduced tricuspid annular systolic velocity (p=0.008). Multivariate analysis identified indexed RV end-diastolic dimension as the only significant determinant of plasma BNP levels (beta=0.69, p<0.001). Plasma BNP levels correlated positively with indexed RV end-diastolic volume (r=0.6, p=0.009) and pulmonary regurgitant fraction (r=0.54, p=0.026), and negatively with exercise duration (r=-0.45, p=0.021), peak oxygen consumption (r=-0.43, p=0.03), and minute ventilation at maximal exercise (r=-0.52, p=0.006). Multivariate analysis demonstrated BNP levels (beta=-0.43, p=0.034) and body mass index (beta=-0.40, p=0.036) to be independent predictors of peak oxygen consumption. No relations were found between BNP levels and RV myocardial performance index, tricuspid annular velocities and RV ejection fraction. CONCLUSIONS: In adolescent patients after TOF repair, plasma BNP levels relate to RV volume overload, pulmonary regurgitation and exercise capacity.

Adolescent↗

PubMed2003

Administration of growth hormone to patients with advanced cardiac heart failure: effects upon left ventricular function, exercise capacity, and neurohormonal status.

Experimental and clinical studies have shown that the administration of recombinant human growth hormone can improve deteriorated left ventricular function and hemodynamics in patients with heart failure. Herein, we compared the effects of growth hormone versus placebo upon resting left ventricular ejection fraction, exercise capacity and neurohormonal status in patients with advanced heart failure. Nineteen patients with advanced cardiac heart failure (ejection fraction <30%) were studied at baseline and after 8 weeks of treatment with growth hormone (0.03 U/kg per day) or placebo. Primary end points were resting left ventricular ejection fraction, peak oxygen consumption and neurohormonal status, including plasma norepinephrine levels and insulin like growth factor-1 and its binding protein-3. Results are presented as median and interquartile ranges. Patients receiving growth hormone had a significant increase in insulin growth factor-1 plasma levels (median difference growth hormone=83 ng/ml [57-170] versus placebo=-6 ng/ml [-23-6], P<0.05) and its binding protein-3. However, no significant increase in left ventricular ejection fraction after growth hormone treatment (ejection fraction pre=16% [13-18] and post=17% [14-27]) was noticed when compared to placebo (ejection fraction pre=20% [15-24] and post=20% [15-26]). Also, no significant effect of growth hormone treatment was seen on peak oxygen consumption or norepinephrine plasma levels. Although the administration of growth hormone to patients with advanced cardiac heart failure was associated with a significant increase in insulin growth factor-1, there were no significant changes in ejection fraction, exercise capacity and/or neurohormonal status.

Aged↗

PubMed2003

Tidal expiratory flow limitation, dyspnoea and exercise capacity in patients with bilateral bronchiectasis.

In this study the authors investigated whether expiratory flow limitation (FL) is present during tidal breathing in patients with bilateral bronchiectasis (BB) and whether it is related to the severity of chronic dyspnoea (Medical Research Council (MRC) dyspnoea scale), exercise capacity (maximal mechanical power output (WRmax)) and severity of the disease, as assessed by high-resolution computed tomography (HRCT) scoring. Lung function, MRC dyspnoea, HRCT score, WRmax and FL were assessed in 23 stable caucasian patients (six males) aged 56 +/- 17 yrs. FL was assessed at rest both in seated and supine positions. To detect FL, the negative expiratory pressure (NEP) technique was used. The degree of FL was rated using a five-point FL score. WRmax was measured using a cyclo-ergometer. According to the NEP technique, five patients were FL during resting breathing when supine but not seated, four were FL both seated and supine, and 14 were NFL both seated and supine. Furthermore, it was shown that: 1) in stable BB patients FL during resting breathing is common, especially in the supine position; 2) the degree of MRC dyspnoea is closely related to the five-point FL score; 3) WRmax (% pred) is more closely correlated with the MRC dyspnoea score than with the five-point FL score; and 4) HRCT score is closely related to forced expiratory volume in one second % pred but not five-point FL score. In conclusion, flow limitation is common at rest in sitting and supine positions in patients with bilateral bronchiectasis. Flow limitation and reduced exercise capacity are both associated with more severe dyspnoea. Finally, high-resolution computed tomography scoring correlates best with forced expiratory volume in one second.

Adult↗

PubMed1987

Relation between lung function, exercise capacity, and exposure to asbestos cement.

A group of 137 male workers with known exposure (mean 20 fibre years per millilitre) to asbestos cement who had symptoms or signs of pulmonary disease was studied together with a reference group of 49 healthy industrial workers with no exposure to asbestos. Lung function measurements were made at rest and during exercise. Evidence of lung fibrosis was found as well as of obstructive airways disease in the exposed group compared with the reference group. Asbestos cement exposure was related to variables reflecting lung fibrosis but not to variables reflecting airflow obstruction. Smoking was related to variables reflecting obstructive lung disease. Exercise capacity was reduced in the exposed workers and was related to smoking and to lung function variables, reflecting obstructive airways disease. There was no significant correlation between exercise capacity and exposure to asbestos cement.

Asbestos↗

PubMed2004

Effects of respiratory muscle weakness on daily living function, quality of life, activity levels, and exercise capacity in mild to moderate Parkinson's disease.

OBJECTIVE: To investigate respiratory muscle strength in mild to moderate Parkinson's disease in comparison with prediction equations and age-matched controls. To identify correlations between respiratory muscle strength and daily living function, activity levels, quality of life, and exercise capacity. DESIGN: A total of 66 participants with Parkinson's disease and 32 age-matched, healthy controls participated. Respiratory mouth pressures (representing respiratory muscle strength) were compared with predicted values. A comparison was also made between participants with Parkinson's disease and age-matched controls. Respiratory mouth pressures were correlated with results of the Barthel index (daily living function), a modified Baecke activity questionnaire (activity levels), the Parkinson's disease questionnaire (quality of life in Parkinson's disease), peak heart rate, peak oxygen consumption, blood lactate thresholds, and the number of stages completed during an incremental cycle ergometer test (representing exercise capacity). RESULTS: Respiratory mouth pressures were significantly lower (P < 0.05) in the Parkinson's disease group, but this did not influence the measures of daily living function, activity levels, and quality of life. Respiratory mouth pressures correlated with lactate thresholds (r = 0.308, P < 0.01) and the number of completed stages of the cycle ergometer test (r = 0.490, P < 0.01). CONCLUSIONS: In mild to moderate Parkinson's disease, there is a significant weakness of the respiratory muscles. This can affect the individual during exercise but has no apparent effect on activities that do not require a large effort of the respiratory muscles.

Activities of Daily Living↗

PubMed1995

Lung function and exercise capacity in survivors of childhood leukaemia.

The survival from acute lymphoblastic leukaemia in childhood is now approximately 60-70%, and from acute myeloid leukaemia, up to 50%. However, there is little information on the effects of intensive chemotherapy and radiotherapy used in the treatment of these conditions on lung function and exercise capacity in the long term. Severity survivors of acute leukaemia from one centre in the UK were studied. Measurements of lung volumes, spirometry and transfer factor were made. Each child also performed a standard, symptom-limited maximal exercise test on a cycle ergometer. Predictive equations for indices of lung function and exercise tolerance were calculated from 146 age- and sex-matched control subjects. The results of the survivors of leukaemia were compared to these. There was a significant reduction of forced expiratory volume in one second (FEV1), forced vital capacity (FVC), total lung capacity (TLC), and transfer for carbon monoxide (DLCO; P < 0.05 for each measurement), in the survivors of leukemia when compared to the control subjects. In addition, there was a mild but significant reduction of both maximal and submaximal indices of exercise capacity in the leukaemic group. A multivariate analysis was carried out to identify those variables acting independently to reduce lung volumes. For FEV1, FVC and TLC, these were craniospinal irradiation, cyclophosphamide and chest complications during treatment. For a reduction in DLCO, the significant factors were administration of anthracyclines, craniospinal irradiation and bone marrow transplantation. Survivors of acute leukemia have impaired pulmonary function and exercise capacity. Long-term cardiopulmonary follow-up may be necessary and new regimens devised which reduce long-term toxicity without compromising survival rates.

Adolescent↗

PubMed2005

Low-dose GH improves exercise capacity in adults with GH deficiency: effects of a 22-month placebo-controlled, crossover trial.

Fifty-five patients with adult-onset GH deficiency (mean age, 49 years) were enrolled in a placebo-controlled, crossover study to investigate the effects of GH therapy on exercise capacity, body composition, and quality of life (QOL). GH and placebo were administered for 9 months each, separated by a 4-month washout period. GH therapy was individually dosed to obtain an IGF-I concentration within the normal range for age and sex. The final mean daily dose of GH was 1.2 IU/day for men and 1.8 IU/day for women. Mean IGF-I concentration at baseline was higher in men than in women (95+/-33 vs 68+/-41 microg/l respectively; P < 0.04) and increased to a similar level on GH therapy. Body fat mass was reduced by 1.9+/-2.9 kg and lean body mass was increased by 1.8+/-2.8 kg (P = 0.0001 for each) with GH treatment. Total and low-density cholesterol levels decreased. Absolute maximal oxygen uptake increased by 6% (P = 0.01), relative to body weight by 9% (P = 0.004), and there was a trend toward increased endurance performance by 7% (P = 0.07). There were no significant effects on QOL. In conclusion, treatment with a low, physiologic dose of GH produced positive effects on body composition and lipids and improved exercise capacity, likely to be of clinical relevance. No changes in QOL were seen, possibly because of a good QOL at baseline.

Adult↗

PubMed2005

Supportive nutrition on recovery of metabolism, nutritional state, health-related quality of life, and exercise capacity after major surgery: a randomized study.

BACKGROUND & AIMS: The aim of this study was to investigate whether specialized supportive enteral and parenteral feeding have superior effects compared to oral nutrition on recovery during long-term postoperative treatment of cancer patients with preoperative weight loss and reduced maximum exercise capacity. METHODS: One hundred twenty-six patients referred for resection of the esophagus (n = 48), stomach (n = 28), or pancreas (n = 50) were considered to be included before operation. Included patients (n = 80) received supportive enteral or parenteral nutrition postoperatively at home corresponding to 1000 kcal/d until the patients did not wish to continue with artificial nutrition for any reason. Patients randomized to oral nutrition only served as control subjects. Caloric intake, body composition (dual-energy x-ray absorptiometry), and respiratory gas exchanges at rest and during exercise were measured including health-related quality of life. RESULTS: Survival and hospital stay did not differ among the groups, whereas overall complications were higher on artificial nutrition (P < .05). Changes in resting energy expenditure and biochemical tests did not differ during follow-up among the groups. Body weight and whole body fat declined similarly over time in all groups (P < .005), whereas lean body mass was unchanged during follow-up compared to preoperative values. Maximum exercise capacity and maximum oxygen consumption were normalized within 6 months postoperatively in all groups. There was no difference in recovery of food intake among the groups. Parenteral feeding was associated with the highest rate of nutrition-related complications, whereas enteral feeding reduced quality of life most extensively. CONCLUSION: After major surgery, specialized supportive enteral and parenteral nutrition are not superior to oral nutrition only when guided by a dietitian.

Body Composition↗

PubMed1995

Metoprolol treatment for two years after coronary bypass grafting: effects on exercise capacity and signs of myocardial ischaemia.

OBJECTIVE: To evaluate whether prophylactic treatment with metoprolol for two years after coronary artery bypass grafting improves working capacity and reduces the occurrence of myocardial ischaemia in patients with coronary artery disease. METHODS: After coronary artery bypass grafting, patients were randomised to treatment with metoprolol or placebo for two years. Two years after randomisation, a computerised 12-lead electrocardiogram was obtained during a standardised bicycle exercise test in 618 patients (64% of all those randomised). RESULTS: The median exercise capacity was 140 W in the metoprolol group (n = 307) and 130 W in the placebo group (n = 311) (P > 0.20). An ST depression of > or = 1 mm at maximum exercise was present in 34% of the patients in the metoprolol group and 38% in the placebo group (P > 0.20) and an ST depression of > or = 2 mm at maximum exercise was present in 11% in the metoprolol group and 16% in the placebo group (P = 0.09). The median values for maximum systolic blood pressure were 200 mm Hg in the metoprolol group and 210 mm Hg in the placebo group (P < 0.0001), while the median values for maximum heart rate were 126 beats/min in the metoprolol group and 143 beats/min in the placebo group (P < 0.0001). The occurrence of cardiac and neurological clinical events two years postoperatively among exercised patients was comparable in the treatment groups. CONCLUSIONS: Treatment with metoprolol for two years after coronary artery bypass grafting did not significantly change exercise capacity or electrocardiographic signs of myocardial ischaemia.

Adrenergic beta-Antagonists↗

PubMed1990

Exercise capacity, arrhythmias, humoral and chemical parameters during long-term therapy with xamoterol.

In order to assess potential harmful effects of the partial beta-1 agonist xamoterol during long-term therapy, we randomly assigned 30 patients with coronary arterial disease and heart failure in classes II and III of the classification of the New York Heart Association to 200 mg of xamoterol twice daily or placebo during a treatment period of 3 months. A supine bicycle exercise test was performed at baseline and after three months in order to assess changes of exercise capacity. Blood samples for determination of creatinine, electrolytes, renin and norepinephrine were withdrawn simultaneously. Twenty-four hour ambulatory Holter electrocardiograms were performed before study, at the end of the study and 72 hours after withdrawal of study medication. On xamoterol, exercise capacity increased from 21.9 +/- 9.7 to 27.8 +/- 14.8 kilojoule (P = 0.032) compared to baseline levels. Exercise duration increased from 340 +/- 115 to 400 +/- 144 seconds (P = 0.043). Heart rate decreased by 10% (P = 0.05) at the 50 watt level and by 10% (P = 0.024) on maximum exercise compared to the baseline values. The rate pressure product was unchanged at rest and dropped by 11% (P = 0.038) on maximum exercise. In contrast, on placebo no significant changes occurred. During xamoterol therapy no changes of blood pressure, electrolytes, renal function and the time-intervals of electrocardiogram were observed. Xamoterol did not enhance arrhythmias during 24-hour ambulatory Holter monitoring. No serious side effects were observed. Xamoterol would appear to be a suitable and safe drug in the therapy of mild to moderate heart failure.

Adrenergic beta-Agonists↗

PubMed2000

Left ventricular outflow tract gradient decrease with non-surgical myocardial reduction improves exercise capacity in patients with hypertrophic obstructive cardiomyopathy.

OBJECTIVES: This study was undertaken to evaluate mid-term clinical results of non-surgical myocardial reduction in patients with hypertrophic obstructive cardiomyopathy. METHODS: Twenty-five patients with left ventricular outflow tract obstruction (mean gradient of 84. 54+/-31.38 mmHg) and symptoms of dyspnoea, angina and/or syncope were treated with non-surgical myocardial reduction. The patients were followed-up for a mean period of 10.44+/-1.8 months. In all patients clinical examination with echocardiography was repeated after every 3 months of follow-up, and a symptom-limited treadmill test was repeated at the 6 month follow-up. Eighteen patients underwent simultaneous respiratory gas analysis. RESULTS: Clinical follow-up examinations were achieved in all 25 patients. Persistent left ventricular outflow tract gradient reduction was seen in 23 patients. Seventeen patients had a reduction of left ventricular outflow tract gradient >50% of baseline value. Twenty patients showed a clinical improvement from 2.8+/-0.5 up to 1.2+/-0.5 NYHA class (P<0.001). The clinical improvement was matched by an improvement in objective measures of exercise capacity in patients with significant left ventricular outflow tract gradient reduction. Exercise time increased from 571.9+/-192.2 to 703.5+/-175.4 s, P<0. 001, and peak VO(2)increased from 14.6+/-5.2 to 20.5+/-8.6 ml. kg(-1)min(-1), P<0.05. CONCLUSION: Significant left ventricular outflow tract gradient reduction with exercise capacity improvement was achieved in the majority of patients treated with non-surgical myocardial reduction. We recommend this method as an alternative to surgery for symptomatic patients with hypertrophic obstructive cardiomyopathy.

Cardiac Catheterization↗

PubMed2003

Striking similarities in systemic factors contributing to decreased exercise capacity in patients with severe chronic heart failure or COPD.

AIMS: Chronic heart failure (CHF) and COPD are both characterized by muscular impairment. To assess whether the severity and functional consequences of muscular impairment are disease specific, we compared skeletal muscle function, body composition, and daily activity level relative to exercise capacity between these two disorders. METHODS: Twenty-five patients with CHF and 25 patients with COPD, and 36 healthy gender- and age-matched control subjects underwent measurement of fat-free mass (FFM) [by bioelectrical impedance analysis] as an index of muscle mass. Quadriceps and biceps functions were tested by isokinetic methods, and daily activity level was assessed by the Physical Activity Scale for Elderly (PASE) questionnaire. Peak oxygen consumption (O(2)peak) was measured by incremental cycle ergometry. RESULTS: PASE results were similar in patients with CHF and in patients with COPD, each group scoring lower than control subjects. FFM was also lower in patients than control subjects and correlated closely with quadriceps and biceps strength in all three subgroups, R values ranging from 0.63 to 0.78, with identical slopes. FFM also correlated significantly with O(2)peak (p < 0.05), but slopes were less steep in patients than in control subjects. The type and severity of muscle dysfunction were similar in each group of patients. There were no significant correlations between indexes of cardiopulmonary function and muscle function or exercise performance in patients with CHF or in patients with COPD. In both control subjects and patients, FFM was the most significant determinant of O(2)peak. CONCLUSION: Muscle dysfunction is not limited to the lower limbs, but generalized and comparable between patients with CHF and patients with COPD with similar exercise capacity. FFM is a strong predictor of peripheral muscle strength, to a lesser extent of O(2)peak, and not at all of peripheral muscle endurance.

Activities of Daily Living↗