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PubMed1994

Factors affecting the postoperative exercise capacity of patients with mitral stenosis and aortic regurgitation.

Factors affecting the exercise capacity of patients with mitral stenosis (MS) and aortic regurgitation (AR) are incompletely understood. Accordingly, exercise capacity was assessed in 13 patients with MS and in 13 with AR by means of cardiopulmonary exercise testing before as well as 3, 6 and 12 months after valve replacement. Left- and right-ventricular function were evaluated echocardiographically. Both in MS and in AR exercise capacity expressed by maximal oxygen consumption (VO2max) increased significantly after valve replacement and was directly related to right ventricular (RV) function assessed by the ratio of RV acceleration time to RV ejection time (r = 0.87, p < 0.001 and r = 0.74, p < 0.001, respectively) and inversely related to left atrial diameter (r = -0.72, p < 0.001 and r = -0.76, p < 0.001, respectively). No relation between VO2max and resting left-ventricular function was found. Thus, the postoperative improvement in the exercise capacity both in mitral stenosis and in aortic regurgitation is associated with an improvement in right-ventricular function and a decrease in left-atrial size.

Aortic Valve Insufficiency↗

PubMed1997

Respiratory oxygen cost for dead space challenge is characteristically increased during exercise in patients with chronic heart failure: does it further decrease exercise capacity?

BACKGROUND: Although the work of the respiratory muscles is markedly increased during exercise in patients with chronic heart failure, the role of this abnormality in exercise intolerance is still controversial. This issue may be clarified directly by dead space challenge, as this technique increases minute ventilation. Therefore, in this study, the effects of an external dead space on exercise ventilation, gas exchange data, and exercise capacity in patients with chronic heart failure were examined. METHODS AND RESULTS: Dead space challenge was performed by adding an external dead space to the airway in 20 patients with chronic heart failure and 10 normal subjects. Two hours after completion of the control maximal bicycle exercise, the second exercise was performed under application of an external dead space equivalent to 10% of peak tidal volume. Respiratory gas exchange data were collected during exercise. Aerobic exercise capacity was assessed from the exercise time and the time to anaerobic threshold. The sensation of exertional dyspnea was assessed using Borg's rating scale. As compared with data during the control exercise, minute ventilation was increased by approximately 25% with the external dead space throughout exercise in both groups. A parallel 20% increase in systemic oxygen uptake was observed in the heart failure group, likely reflecting an increase in respiratory muscle work. This response was not observed in the normal group. Despite an additional increase in respiratory muscle work, neither aerobic exercise capacity nor exertional dyspnea was exacerbated in the heart failure group by the external dead space. CONCLUSIONS: Dead space challenge appears to be a unique technique that characteristically increases the work of respiratory muscles during exercise in patients with chronic heart failure. By use of this technique, it was demonstrated that an increase in respiratory muscle work is not important in reducing exercise capacity of patients with chronic heart failure.

Adult↗

PubMed2000

Long-term estrogen replacement therapy is associated with improved exercise capacity in postmenopausal women without known coronary artery disease.

BACKGROUND: Short-term estrogen administration improves vasodilation and has been shown to improve exercise capacity. However, it is unknown whether long-term estrogen replacement therapy is associated with improved exercise capacity in postmenopausal women without known coronary artery disease. METHODS AND RESULTS: We studied 248 postmenopausal women without known coronary artery disease (mean age 63.5 years); 158 (64%) were current or past hormone replacement therapy (HRT) users and 108 (44%) were current users of HRT. Attributes potentially affecting exercise capacity and cardiac risk factors were carefully measured. These included duration of estrogen replacement therapy, all variables in the Framingham risk index, physical activity level, body mass index, waist-to-hip ratio, presence of osteoporosis, and family history of heart disease. We measured maximal oxygen uptake (MVO (2)) and anaerobic threshold as objective markers of exercise capacity. The relation between exercise capacity and use of HRT was analyzed with the use of logistic regression, controlling for confounding variables. We found that fitness, as measured by MVO (2) and anaerobic threshold, was significantly greater in women who had used HRT currently or in the past compared with women who had never used HRT. This difference in fitness was not confounded by age or physical activity level. CONCLUSIONS: Estrogen replacement therapy is associated with increased exercise capacity as measured by MVO (2) and anaerobic threshold in postmenopausal women without coronary artery disease. This finding is consistent with the beneficial effect of short-term estrogen administration on improved endothelium-dependent and endothelium-independent vasodilation.

Aged↗

PubMed1986

Carnitine status, plasma lipid profiles, and exercise capacity of dialysis patients: effects of a submaximal exercise program.

Carnitine status, blood lipid profiles, and exercise capacity were evaluated in a combined group of hemodialysis (N = 4) and continuous ambulatory peritoneal dialysis (N = 6) patients before and after an 8-week submaximal exercise program. Maximal aerobic capacity (VO2max) was only 18.5 +/- 5.9 (mean +/- SD) mL O2/kg/min, well below the expected 30 to 35 mL O2/kg/min for age-matched sedentary controls. Plasma short-chain acylated carnitine levels, which were two to three times normal values, were reduced after the exercise program, but the long-chain acylcarnitines were significantly reduced during acute exercise. Muscle biopsies of the vastus lateralis were performed at rest in five patients prior to and after the 8-week exercise program. Total carnitine in skeletal muscle was 3.09 (.076 SD) mumol/g ww, with only 11.3% acylated prior to the exercise program, which was much lower than the 4.25 +/- 1.27 mumol/g ww, with 28.5% acylated in a group of healthy athletic subjects (N = 28). Muscle free carnitine concentrations decreased significantly following the 8-week training period, with only a slight reduction in total carnitine. The percent of acylated carnitine was therefore significantly increased (P less than 0.05) from 11.3% to 25.2% after the experimental period. Pretraining carnitine palmitoyl transferase activity at rest was 0.57 +/- 0.28 nmol palmitoyl carnitine formed/5 min/mg mitochondrial protein, which was not changed by exercise training v 1.80 +/- 0.51 nmol/5 min/mg protein in 28 healthy normals (P less than 0.001). Free fatty acid concentrations were reduced significantly during acute exercise as a result of the exercise training program whereas other plasma lipids were not altered. (ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1995

Exercise capacity in hypertrophic cardiomyopathy. Role of stroke volume limitation, heart rate, and diastolic filling characteristics.

BACKGROUND: We previously showed that exercise capacity in patients with hypertrophic cardiomyopathy (HCM) is related to peak exercise cardiac output. Cardiac output augmentation during exercise is normally dependent on heart rate (HR) response and stroke volume (SV) augmentation by increased left ventricular end-diastolic volume and/or increased contractility. We hypothesized that in contrast to normal subjects, peak exercise capacity in patients with HCM is determined by the diastolic filling characteristics of the left ventricle during exercise, which would in turn determine the degree to which SV is augmented, and that HR is a relatively unimportant determinant of peak exercise capacity. METHODS AND RESULTS: Twenty-three patients with HCM underwent invasive hemodynamic evaluation and measurement of maximal oxygen consumption (VO2max) during erect treadmill exercise to assess the relative importance of changes in HR and SV in determining exercise capacity. Hemodynamic responses to erect and supine exercise were compared in 10 of these patients. In a separate group of 46 patients with HCM, the relation between VO2max and exercise diastolic filling indexes was assessed. Peak HR during erect exercise was 92 +/- 8% of predicted maximum. VO2max was 29.0 +/- 6.4 mL.kg-1.min-1 and was related significantly to peak exercise cardiac index and SV index (r = .71, P < .001 and r = .66, P = .001, respectively) but not to peak HR, HR deficit, or resting or peak pulmonary capillary wedge pressure. Peak cardiac output during erect exercise was not related to peak HR (r = .13, P = NS). When erect and supine exercise were compared, peak HR was lower in the supine position (153.3 +/- 19.9 beats per minute supine versus 172.0 +/- 17.6 beats per minute erect, P = .003), but peak exercise cardiac index was similar (7.9 +/- 2.6 L.min-1.m-2 supine versus 7.5 +/- 2.8 L.min-1.m-2 erect). Pulmonary capillary wedge pressure was higher at rest in the supine versus erect position (15.3 +/- 5.2 versus 8.1 +/- 6.1 mm Hg) but was not significantly higher at peak exercise in the supine versus erect position (28.5 +/- 8 versus 22.4 +/- 11.6 mm Hg erect, P = NS). In the separate group of 46 patients with HCM, VO2max was significantly inversely related to time to peak filling at peak exercise (r = -.60, P < .0001) but did not correlate with time to peak filling at rest, resting ejection fraction, peak filling rate, or peak exercise peak filling rate. CONCLUSIONS: SV is the major determinant of peak exercise capacity in the erect position in patients with hypertrophic cardiomyopathy. This in turn is determined by the exercise left ventricular diastolic filling characteristics. HR augmentation does not appear to be a major determinant of peak cardiac output in the erect position.

Adult↗

PubMed1997

Exercise capacity after His bundle ablation and rate response ventricular pacing for drug refractory chronic atrial fibrillation.

OBJECTIVE: To evaluate exercise capacity of patients with chronic atrial fibrillation in whom His bundle ablation followed by ventricular rate response pacing (VVIR) was carried out because of drug refractoriness. DESIGN: Prospective study. PATIENTS: 25 consecutive patients, all with chronic symptomatic drug refractory atrial fibrillation, underwent His bundle ablation. Before this intervention all patients were on antiarrhythmic drugs to attain acceptable heart rate control and to relief symptoms. MAIN OUTCOME MEASURES: Exercise capacity, including measurements of VO2, was examined before and after a mean interval of seven months following His bundle ablation. RESULTS: Exercise capacity after His bundle ablation increased from a mean of 109 (SD 49) W to 118 (46) W (P < 0.002), but VO2 at peak exercise did not change significantly. Maximum exercise capacity was achieved with a significantly lower maximum driven heart rate than the spontaneous heart rate before ablation. CONCLUSIONS: Exercise capacity of patients who underwent His bundle ablation followed by VVIR pacing remained unchanged or improved during a mean follow up of seven months. Larger patient populations with longer follow up are necessary to examine determinants of improved exercise capacity.

Atrial Fibrillation↗

PubMed1994

[Cardiopulmonary exercise capacity before and after heart transplantation].

The aim of heart transplantation is to improve survival and exercise capacity of patients with endstage heart failure. Fifteen patients (1 female, 14 male) with a mean age of 48 years (ranging from 25-62) underwent cardiopulmonary exercise testing (CPX) before heart transplantation. 10/15 patients showed an oxygen uptake of < 4 ml/min/kg (Weber E) at the anaerobic threshold and 5/15 an oxygen uptake between 5 and 8 ml/min/kg (Weber D), so that a severe respectively very severe limitation of exercise capacity was documented before transplantation. Up to now 9/15 patients underwent heart transplantation. Cardiopulmonary exercise test could be repeated in 7 of these 9 patients, 12 up to 22 weeks following operation. Exercise capacity improved from former Weber-class E to class B in 2/5 patients, to class C in 2/5 patients, and to class D in 1/5 patient. Both patients with a preoperative class D improved to class C. Thus, in all cardiac recipients exercise capacity increased, whereas normal values were not reached. The denervation of cardiac allografts leads to a higher heart rate at rest, a delayed increase and diminished slope of exercise response and reduced heart rates at maximal effort. In 17 heart transplant recipients (3 female, 14 male) with a mean age of 53 years (ranging from 25-62), we investigated the exercise capacity with respect to the abnormal rate regulation of the donor heart, which was quantified by comparing the corresponding rate regulation of the remaining part of recipient's atrium driven by the sinus mode.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed2000

Low-dose enoximone improves exercise capacity in chronic heart failure. Enoximone Study Group.

OBJECTIVES: This study was designed to evaluate the effects of low-dose enoximone on exercise capacity. BACKGROUND: At higher doses the phosphodiesterase inhibitor, enoximone, has been shown to increase exercise capacity and decrease symptoms in heart failure patients but also to increase mortality. The effects of lower doses of enoximone on exercise capacity and adverse events have not been evaluated. METHODS: This is a prospective, double-blind, placebo-controlled, multicenter trial (nine U.S. centers) conducted in 105 patients with New York Heart Association class II to III, ischemic or nonischemic chronic heart failure (CHF). Patients were randomized to placebo or enoximone at 25 or 50 mg orally three times a day. Treadmill maximal exercise testing was done at baseline and after 4, 8 and 12 weeks of treatment, using a modified Naughton protocol. Patients were also evaluated for changes in quality of life and for increased arrhythmias by Holter monitoring. RESULTS: By the protocol-specified method of statistical analysis (the last observation carried-forward method), enoximone at 50 mg three times a day improved exercise capacity by 117 s at 12 weeks (p = 0.003). Enoximone at 25 mg three times a day also improved exercise capacity at 12 weeks by 115 s (p = 0.013). No increases in ventricular arrhythmias were noted. There were four deaths in the placebo group and 2 and 0 deaths in the enoximone 25 mg three times a day and enoximone 50 mg three times a day groups, respectively. Effects on degree of dyspnea and patient and physician assessments of clinical status favored the enoximone groups. CONCLUSIONS: Twelve weeks of treatment with low-dose enoximone improves exercise capacity in patients with CHF, without increasing adverse events.

Adolescent↗

PubMed1995

Effects of recombinant human erythropoietin and exercise training on exercise capacity in hemodialysis patients.

The effects of recombinant human erythropoietin (rHuEPO) and exercise training on exercise capacity were evaluated in 20 hemodialysis patients. After improvement of anemia by rHuEPO (Phase I), patients were divided into 2 groups. Group 1, 10 patients, was placed in a 3-month exercise training program. Group 2, 10 patients, served as a control group (Phase 2). A symptom-limited exercise tolerance test was performed at the start of Phase 1 and before and after Phase 2. Hemoglobin (Hb) values were kept constant throughout Phase 2. In Phase 1, maximum workloads (62.0 +/- 19.1 to 76.5 +/- 25.6 W, p < 0.001), maximum O2 uptake (VO2max) (18.7 +/- 3.5 to 2.2 +/- 5.9 ml/min/kg, p < 0.01), and VO2 at anaerobic threshold (AT) (VO2AT) (8.5 +/- 2.1 to 10.2 +/- 2.9 ml/min/kg, p < 0.01) were all improved by rHuEPO. However, in Phase 2, despite unchanged Hb values and maximum workloads, VO2max (20.7 +/- 4.6 to 17.6 +/- 2.6 ml/min/kg, p < 0.05) and VO2AT (10.6 +/- 1.4 to 9.5 +/- 1.8, ml/min/kg p < 0.05) were decreased in Group 2. However, in Group 1, maximum workloads (66.7 +/- 8.2 to 81.7 +/- 7.5 W, p < 0.01) were improved, and VO2max and VO2AT were not decreased significantly in the same period. Exercise training in rHuEPO-treated hemodialysis patients resulted in an improved aerobic exercise capacity, whereas those without exercise training did not have increased capacity. Throughout the study, O2 uptakes were lower than those of nonrenal anemic patients who had similar Hb values. Maximum lactate values also remained low. In conclusion, improvement in the exercise capacity in hemodialysis patients treated with rHuEPO was minimal. Some defects were suggested in the aerobic energy production system in skeletal muscle of dialysis patients. Anemia-improved patients should participate in incremental physical activity to maintain an improved exercise capacity.

Adult↗

PubMed1986

Exercise capacity and cardiac function in type 1 diabetic patients treated with continuous subcutaneous insulin infusion. A controlled study.

In order to investigate the effect of improved glycaemic control on exercise capacity and cardiac function, bicycle exercise and echocardiography at rest and after exercise was performed in 24 short-term type 1 diabetic patients, randomized to conventional insulin therapy (CIT) or to continuous subcutaneous insulin infusion (CSII). After 6 months significant improvement in glycaemic control was seen in the CSII group showing a decrease in mean blood glucose and haemoglobin A1c (HbA1c), while no change was observed in the CIT group. Exercise capacity increased by 24% (p less than 0.01) in the CSII group and decreased by 16% (NS) in the CIT group. In the CSII group fractional shortening of the left ventricle during rest decreased by 14% (p less than 0.02), while an increase of 2% (NS) was seen in the CIT group. Further, changes of left ventricular fractional shortening during rest were inversely correlated to changes in exercise capacity. After exercise, fractional shortening of the left ventricle and rate-pressure product was unchanged in the two groups. In conclusion this study shows a beneficial effect of improved glycaemic control induced by CSII on exercise capacity possibly by reducing resting state demands to the cardiovascular system.

Adult↗

PubMed1990

Relation of diastolic function and exercise capacity in ischemic left ventricular dysfunction. Role of beta-agonists and beta-antagonists.

The relation between global left ventricular function at rest (evaluated during cardiac catheterization) and exercise capacity was examined in a group of 33 untreated patients with a previous anterior myocardial infarction. The resting ejection fraction (range, 24-68%) correlated poorly with exercise duration (r = 0.47) and did not separate patients with a depressed exercise capacity (exercise duration less than 500 seconds: group A, n = 18) from patients with preserved exercise tolerance (group B, n = 15). The resting left ventricular end-diastolic and end-systolic volume indexes were comparable in groups A and B, but the diastolic pressure-volume relation was shifted upward, and the mean left ventricular pressure during diastolic filling was higher in group A than in group B (19 +/- 8 versus 14 +/- 4 mm Hg; p less than 0.02). The heart rate at maximal exercise was similar in both groups (160 +/- 16 versus 160 +/- 17 beats/min; NS), but heart rate was higher at any given level of exercise in group A than in group B. When 12 patients of group A were treated with xamoterol, a beta 1-adrenoceptor partial agonist, their exercise duration increased by 20 +/- 14% (p less than 0.001), and their maximal exercise heart rate decreased from 158 +/- 16 to 143 +/- 11 beats/min (p less than 0.001). This improved exercise capacity was accompanied by a downward shift of the resting diastolic left ventricular pressure-volume relation and by a decrease in mean left ventricular pressure during diastolic filling.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenergic beta-Agonists↗

PubMed1990

The correlation of cardiac power output to exercise capacity in chronic heart failure.

Cardiac haemodynamics are deranged in chronic heart failure but fail to predict the exercise capacity of the patient. Cardiac power output is a descriptor of cardiac function derived from preload, blood pressure and cardiac output. Forty-one patients with moderately severe and severe chronic heart failure were exercised on a cycle ergometer to determine the relationship between traditional haemodynamics and cardiac power output and exercise capacity. Resting cardiac power output was no more predictive of exercise capacity than resting stroke-work index or resting cardiac index (r = 0.53, 0.61 and 0.51 respectively). Maximum cardiac power output and the ability to increase cardiac power output, however, were correlated with exercise capacity (r = 0.79 and 0.80). It is concluded that resting cardiac power output does not predict subsequent exercise capacity but that maximum cardiac power output and the ability to increase cardiac power output on stimulation are good descriptors of functional cardiac reserve.

Adult↗

PubMed1985

Effects of atenolol on exercise capacity in patients with mitral stenosis with sinus rhythm.

Exercise capacity is frequently impaired in patients with mitral stenosis (MS) and sinus rhythm (SR). The resulting increased heart rate, which shortens the diastolic filling period, and the increased cardiac output lead to further elevations of left atrial pressure and subsequent pulmonary congestion. The effect of the beta-receptor blocking agent atenolol, 100 mg/day, was assessed in 13 patients with MS and SR. Exercise performance was assessed using a modified multistage Bruce protocol after 2 weeks of placebo and after 2 weeks therapy with atenolol in a single-blind, crossover, placebo-controlled, randomized study. Atenolol resulted in significant decreases in mean heart rates at rest and during exercise (p = 0.0015) and a significant increase in total exercise time (p = 0.0015). Maximal exercise capacity was also significantly improved (p = 0.0015). All patients were both objectively and subjectively improved by atenolol. Thus, beta-blockade with atenolol improves exercise capacity in patients with MS and SR and may be of benefit to most such patients. The improved effort tolerance is attributed to reduction of the exercise-associated sinus tachycardia by beta-blockade, allowing a longer diastolic filling period and better left atrial decompression.

Adolescent↗

PubMed1997

Enalapril does not enhance exercise capacity in patients after Fontan procedure.

BACKGROUND: Angiotensin-converting enzyme inhibitors improve exercise capacity in adults with congestive heart failure by decreasing systemic vascular resistance and improving ventricular diastolic function. Patients who have undergone the Fontan procedure have decreased cardiac output, increased systemic vascular resistance, abnormal diastolic function, and decreased exercise capacity compared with normal people. METHODS AND RESULTS: To test the hypothesis that afterload reduction therapy alters hemodynamic variables and augments exercise capacity in patients after a Fontan procedure, we compared the results of graded exercise with maximal effort from 18 subjects (14.5+/-6.2 years of age, 4 to 19 years after Fontan procedure) in a randomized, double-blind, placebo-controlled crossover trial using enalapril (0.2 to 0.3 mg x kg[-1] x d[-1], maximum 15 mg). Each treatment was administered for 10 weeks. Diastolic filling patterns at rest were assessed by Doppler determination of the systemic atrioventricular valve flow velocity at the conclusion of each therapy. No difference was detected in resting heart rate, blood pressure, or cardiac index. Diastolic filling patterns were also similar. Exercise duration was not different (6.4+/-2.6 [enalapril] versus 6.7+/-2.6 minutes [placebo]). The mean percent increase in cardiac index from rest to maximum exercise was slightly but significantly decreased in subjects after 10 weeks of enalapril therapy (102+/-34% [enalapril] versus 125+/-34% [placebo]; P<.02). At maximal exercise, cardiac index (3.5+/-0.9 [enalapril] versus 3.8+/-0.9 L x min[-1] x m2 [placebo]), oxygen consumption (18.3+/-9 [enalapril] versus 20.5+/-7 mL x min[-1] x kg[-1] [placebo]), minute ventilation (57.5+/-17 [enalapril] versus 55.4+/-19 L/min [placebo]), and total work (247+/-181 [enalapril] versus 261+/-197 W [placebo]) were not different. CONCLUSIONS: We conclude that enalapril administration for 10 weeks does not alter abnormal systemic vascular resistance, resting cardiac index, diastolic function, or exercise capacity in patients who have undergone a Fontan procedure.

Adolescent↗

PubMed2003

Determinants of exercise capacity in hypertensive patients: new insights from tissue Doppler echocardiography.

BACKGROUND: Determinants of exercise capacity have not been clearly defined in hypertensive patients. Doppler tissue imaging (DTI), a recently developed echocardiographic modality, is useful for evaluating left ventricular (LV) function regardless of loading conditions. The present study was performed to identify the determinants of exercise capacity in hypertensive patients using DTI. METHODS: We studied 48 hypertensive patients (26 men; mean age, 57 +/- 9 years) with normal LV ejection fraction (>50%). Conventional echocardiographic indexes were measured before and after symptom-limited treadmill exercise. Also, longitudinal systolic (S(L)') and diastolic myocardial velocities (E(L)' and A(L)') and radial velocities (S(R)', E(R)', A(R)') were measured using DTI with the sample volume at the LV basal posterior wall. RESULTS: Mean exercise time was 525 +/- 135 sec. Mean LV ejection fraction was 61% +/- 6%. Mean LV mass index was 110.9 +/- 24.4 g/m(2). On univariate analysis, S(L)', E(L)', A(L)' and percentage increase of S(R)' velocity after exercise showed significant correlation with exercise time. However, only E(L)' and percentage increase of S(R)' remained significant after multivariate analysis. CONCLUSIONS: Left ventricular contractile reserve and relaxation property are important cardiac factors determining exercise capacity. Early diastolic longitudinal myocardial velocity might be useful for identifying hypertensive patients with poor exercise capacity.

Adult↗

PubMed2001

A patient with a severe chronic airway obstruction and preserved exercise capacity (a case report).

We report a patient with chronic obstructive pulmonary disease (COPD) in whom severe lung function disorders are combined with completely preserved exercise capacity. We assessed the exercise capacity of a 44-year-old man (height 155 cm, BMI 19.6 kg.m-2, FEV1%pred. = 30.9%, FRC%pred. = 158%, KCO%pred. = 46.2%, PaO2 = 64.0 mmHg, Medical Research Council Dyspnea scale = 1, Baseline Dyspnea Index = 10) by the 6-minute walking distance test (6MWD) and the symptom-limited cardiopulmonary exercise test (CPET) on a treadmill using the Bruce protocol. The patient was able to walk 667 meters in the test and achieved peak relative oxygen consumption (VO2/kg) of 21.9 mL.min-1.kg-1. We attribute the preserved exercise capacity of the patient to the combined beneficial effect of the following factors: 1. Efficient extraction of the hemoglobin-transported oxygen from the alveoli (P50 = 3.10 kPa). 2. Optimal right ventricle remodelling with mild hypertrophy, without dilatation and congestion. 3. Hypoxic normoxemia without polyglobulia, resulting in good rheologic properties of blood. 4. A preserved locomotory activity of the patient. Such a combination of severe lung function disorders with mildly pronounced dyspnea and preserved exercise capacity supports the concept that the function profile of COPD patients is multidimensional and therefore such patients should have a complete assessment of their disability condition.

Adult↗

PubMed2004

Exercise capacity as a predictor of survival among ambulatory patients with end-stage renal disease.

BACKGROUND: Exercise capacity is reduced in end-stage renal disease (ESRD). Exercise requires the integrated function of multiple vital organs, and low exercise capacity is an independent predictor of mortality in a number of clinical populations. We analyzed the value of exercise capacity, characterized as peak oxygen uptake (VO2), for predicting survival in a cohort of 175 hemodialysis patients over a median follow-up of 39 months. METHODS: Survival status was determined for 175 ESRD patients who had participated in previous studies for which peak VO2 and other clinical data had been determined. Chi-square and Kaplan-Meier survival analyses were performed, and a minimal model of factors related to mortality was developed by Cox multiple regression. RESULTS: There were 23 deaths during the follow-up period. Peak VO2 (>17.5 mL/min/kg) was a powerful predictor of survival (P= 0.009 by Kaplan-Meier). Age (<65 years), dialysis vintage (<39 months), pulse pressure (<54 mm Hg), and absence of diagnoses of diabetes or heart failure were also associated with better survival on univariate analyses. On multivariate analysis peak VO2 contributed significantly to the minimal explanatory model relating clinical variables to mortality (overall chi2= 25.5, P= 0.00001). CONCLUSION: Among these ambulatory ESRD patients, peak VO2 was a stronger predictor of survival than many traditional prognostic variables, some of which are subject to ceiling effects. Exercise capacity may thus provide incremental prognostic information concerning healthier ESRD patients. Because peak VO2 may be modified by exercise training, the potential of exercise as an intervention to improve survival is suggested.

Adult↗

PubMed1994

A nomogram to predict exercise capacity from a specific activity questionnaire and clinical data.

Recent investigations suggested that clinical exercise testing can be optimized by individualizing the protocol, depending on the purpose of the test and the subject tested. This requires some knowledge of a patient's exercise capacity before beginning the test. The accuracy of a simple physical activity questionnaire and readily available clinical data in predicting subsequent treadmill performance was examined. A brief, self-administered questionnaire (VSAQ) was developed for veterans who were referred to exercise testing for clinical reasons. The VSAQ was designed to determine which specific daily activities were associated with symptoms of cardiovascular disease (fatigue, chest pain and shortness of breath). Two hundred twelve consecutive patients (mean age 62 +/- 8 years) referred for maximal exercise testing were studied. Clinical and demographic variables were added to VSAQ responses in a stepwise regression model to determine their ability to predict treadmill performance. Only metabolic equivalents by VSAQ, and age were significant predictors of treadmill performance; these 2 variables yielded R = 0.82 (SEE 1.43; p < 0.001), and explained 67% of the variance in exercise capacity. The regression equation reflecting the relation between age, VSAQ and exercise capacity was: achieved metabolic equivalents = 4.7 + 0.97 (VSAQ) - 0.06 (age). Using this equation, a nomogram was developed. Incorporating the VSAQ with the nomogram requires only a few minutes, and yields a reasonably accurate estimate of a patient's exercise capacity. Although the present equation is population-specific, a similar approach in different populations may be useful for individualizing protocols for clinical exercise testing.

Activities of Daily Living↗