Limited Exercise Performance Research Articles

The Effect of Skeletal Muscle Oxygenation on Hemodynamics, Cerebral Oxygenation and Activation, and Exercise Performance during Incremental Exercise to Exhaustion in Male Cyclists.

This study aimed to elucidate whether muscle blood flow restriction during maximal exercise is associated with alterations in hemodynamics, cerebral oxygenation, cerebral activation, and deterioration of exercise performance in male participants. Thirteen healthy males, cyclists (age 33 ± 2 yrs., body mass: 78.6 ± 2.5 kg, and body mass index: 25.57 ± 0.91 kg·m-1), performed a maximal incremental exercise test on a bicycle ergometer in two experimental conditions: (a) with muscle blood flow restriction through the application of thigh cuffs inflated at 120 mmHg (with cuffs, WC) and (b) without restriction (no cuffs, NC). Exercise performance significantly deteriorated with muscle blood flow restriction, as evidenced by the reductions in V˙O2max (-17 ± 2%, p < 0.001), peak power output (-28 ± 2%, p < 0.001), and time to exhaustion (-28 ± 2%, p < 0.001). Muscle oxygenated hemoglobin (Δ[O2Hb]) during exercise declined more in the NC condition (p < 0.01); however, at exhaustion, the magnitude of muscle oxygenation and muscle deoxygenation were similar between conditions (p > 0.05). At maximal effort, lower cerebral deoxygenated hemoglobin (Δ[HHb]) and cerebral total hemoglobin (Δ[THb]) were observed in WC (p < 0.001), accompanied by a lower cardiac output, heart rate, and stroke volume vs. the NC condition (p < 0.01), whereas systolic blood pressure, rating of perceived exertion, and cerebral activation (as assessed by electroencephalography (EEG) activity) were similar (p > 0.05) between conditions at task failure, despite marked differences in exercise duration, maximal aerobic power output, and V˙O2max. In conclusion, in trained cyclists, muscle blood flow restriction during an incremental cycling exercise test significantly limited exercise performance. Exercise intolerance with muscle blood flow restriction was mainly associated with attenuated cardiac responses, despite cerebral activation reaching similar maximal levels as without muscle blood flow restriction.

Real intensity of physical activity capacity of patients with chronic disease: a cross-sectional study

The aim of this study was to evaluate the real intensity level of exercise in a sample of patients with chronic disease from obesity, rheumatology, hematology and other departments involved in a hospital-based program of adapted physical activity (APA). For this cross-sectional study, we studied seventy-five patients with chronic disease and no beta-blocker treatment. They systematically performed a cardiopulmonary exercise test before participating in a supervised APA practice using a telemetry wireless system to monitor heart rate (HR) during the first session. Based upon the results of the functional evaluation of exercise performance, we studied two groups of patients: (1) No limitation in exercise performance (maximal oxygen uptake greater than or equal to 80% of the theoretical reference) and (2) limited exercise performance (maximal oxygen uptake less than 80% of the theoretical value). Fifty-two patients (69.3%) were women, mean age was 42.6 (± 13.8), and mean BMI was 36.7 (± 10.6). Most patients had been referred for obesity (57.3%). We found 39 patients with normal exercise capacities and 36 patients with limited exercise performance. There were no significant differences in demographic and clinical characteristics between the two groups. For all populations, the mean and median real intensity levels of exercise in a sample of patients were moderate (55–70% HR max) and were the same for both groups. During the most intensive 15-min bout of the APA session, the HR for patients in both groups was greater than 70% of the actual maximum HR. This study observed a moderate level of APA exercise intensity in patients suffering from various chronic diseases. We found no significant difference in intensity level of exercise between patients’ capacities, i.e., with and without limitation of their maximal performance.

Physical Activity Capacity Assessment of Patients with Chronic Disease and the Six-Minute Walk Test: A Cross-Sectional Study.

Background: This study aimed to evaluate the efficacy of the Six-Minute Walk Test (6MWT) to determine the physical activity capacities of patients with chronic disease. Methods: For this cross-sectional study, we investigated 156 patients with chronic disease and no beta-blocker treatment. They systematically performed a maximal cardiopulmonary exercise test to determine their heart rate peak (HRPeak) and maximal oxygen uptake (V’O2max). We considered two groups of patients based upon the results of the functional evaluation of exercise performance: (1) No limitation in exercise performance (V’O2max greater or equal to 80% of the theoretical reference) and (2) limited exercise performance (V’O2max less than 80% of the theoretical value). All patients also received a 6MWT on the same day as the exercise test. Results: We found 68 (43.6%) patients with normal exercise capacities and 88 (56.4%) patients with limited exercise performance. In this sample, 6MWT mean distances were 510 (87) and 506 (86) m, respectively. There were no significant differences between the two groups for distance and end-test heart rate. The correlation between matrix V’O2max measured during the maximal incremental exercise test and the 6MWT distance displayed a positive slope (r = 0.549 CI95 [0.431–0.656]—p < 0.001). Conclusion: Our results showed a moderate relationship between 6MWT and physical activity capacity for patients with chronic disease.

Physical Activity Capacity Assessment of Patients With Chronic Disease and the 1-Minute Sit to Stand Test: Is There an Interest?

ObjectiveThis study aimed to evaluate the efficacy of the 1-minute Sit to Stand test (1MSTS) to determine physical activity capacities for patients with chronic disease.MethodsFor this cross-sectional study, we studied fifty patients with chronic disease and no beta-blocker treatment. They systematically performed a cardiopulmonary exercise test to determine maximal oxygen uptake (V'O2max). We considered two groups of patients based on the results of the functional evaluation of exercise performance: (1) No limitation in exercise performance (V'O2max greater or equal to 80% of the theoretical reference) and (2) limited exercise performance (V'O2max <80% of the theoretical value). All patients also received an 1MSTS on the same day.ResultsWe found 22 (44.0%) patients with normal exercise capacity and 28 (56.0%) patients with limited exercise performance. In this sample, mean 1MSTS repetitions were 27.1 (7.1) and 25.2 (8.7), respectively. There were no significant differences between the two groups for repetition and Borg Scale end test. The correlation between V'O2max measured during the exercise test and 1MSTS repetitions displayed a positive slope [r = 0.401 (95% CI 0.114–625)].ConclusionThis study demonstrated a moderate relationship between 1MSTS and V'O2max for patients with chronic disease. 1MSTS did not permit the precise determination of physical activity capacities in this sample.

Exercise prescription improves exercise tolerance in young children with CHD: a randomised clinical trial

ObjectiveThe main objective of this study was to ascertain if a structured intervention programme can improve the biophysical health of young children with congenital heart disease (CHD). The primary end...

Thoracoabdominal asynchrony associates with exercise intolerance in fibrotic interstitial lung diseases.

The precise coordination of respiratory muscles during exercise minimizes work of breathing and avoids exercise intolerance. Fibrotic interstitial lung disease (f-ILD) patients are exercise-intolerant. We assessed whether respiratory muscle incoordination and thoracoabdominal asynchrony (TAA) occur in f-ILD during exercise, and their relationship with pulmonary function and exercise performance. We compared breathing pattern, respiratory mechanics, TAA and respiratory muscle recruitment in 31 f-ILD patients and 31 healthy subjects at rest and during incremental cycle exercise. TAA was defined as phase angle (PhAng) >20°. During exercise, when compared with controls, f-ILD patients presented increased and early recruitment of inspiratory rib cage muscle (p< 0.05), and an increase in PhAng, indicating TAA. TAA was more frequent in f-ILD patients than in controls, both at 50% of the maximum workload (42.3% vs. 10.7%, p= 0.01) and at the peak (53.8% vs. 23%, p= 0.02). Compared with f-ILD patients without TAA, f-ILD patients with TAA had lower lung volumes (forced vital capacity, p< 0.01), greater dyspnoea (Medical Research Council > 2 in 64.3%, p= 0.02), worse exercise performance (lower maximal work rate % predicted, p= 0.03; lower tidal volume, p= 0.03; greater desaturation and dyspnoea, p< 0.01) and presented higher oesophageal inspiratory pressures with lower gastric inspiratory pressures and higher recruitment of scalene (p< 0.05). Exercise induces TAA and higher recruitment of inspiratory accessory muscle in ILD patients. TAA during exercise occurred in more severely restricted ILD patients and was associated with exertional dyspnoea, desaturation and limited exercise performance.

Quality of life questionnaire predicts poor exercise capacity only in HFpEF and not in HFrEF

BackgroundThe Minnesota Living with Heart Failure Questionnaire (MLHFQ) is the most widely used measure of quality of life (QoL) in HF patients. This prospective study aimed to assess the relationship between QoL and exercise capacity in HF patients.MethodsThe study subjects were 118 consecutive patients with chronic HF (62 ± 10 years, 57 females, in NYHA I-III). Patients answered a MLHFQ questionnaire in the same day of complete clinical, biochemical and echocardiographic assessment. They also underwent a 5 min walk test (6-MWT), in the same day, which grouped them into; Group I: ≤ 300 m and Group II: >300 m. In addition, left ventricular (LV) ejection fraction (EF), divided them into: Group A, with preserved EF (HFpEF) and Group B with reduced EF (HFrEF).ResultsThe mean MLHFQ total scale score was 48 (±17). The total scale, and the physical and emotional functional MLHFQ scores did not differ between HFpEF and HFpEF. Group I patients were older (p = 0.003), had higher NYHA functional class (p = 0.002), faster baseline heart rate (p = 0.006), higher prevalence of smoking (p = 0.015), higher global, physical and emotional MLHFQ scores (p < 0.001, for all), larger left atrial (LA) diameter (p = 0.001), shorter LV filling time (p = 0.027), higher E/e’ ratio (0.02), shorter isovolumic relaxation time (p = 0.028), lower septal a’ (p = 0.019) and s’ (p = 0.023), compared to Group II.Independent predictors of 6-MWT distance for the group as a whole were increased MLHFQ total score (p = 0.005), older age (p = 0.035), and diabetes (p = 0.045), in HFpEF were total MLHFQ (p = 0.007) and diabetes (p = 0.045) but in HFrEF were only LA enlargement (p = 0.005) and age (p = 0.013. A total MLHFQ score of 48.5 had a sensitivity of 67% and specificity of 63% (AUC on ROC analysis of 72%) for limited exercise performance in HF patients.ConclusionsQuality of life, assessment by MLHFQ, is the best correlate of exercise capacity measured by 6-MWT, particularly in HFpEF patients. Despite worse ejection fraction in HFrEF, signs of raised LA pressure independently determine exercise capacity in these patients.

Left atrial emptying fraction predicts limited exercise performance in heart failure patients

AimWe aimed in this study to assess the role of left atrial (LA), in addition to left ventricular (LV) indices, in predicting exercise capacity in patients with heart failure (HF). MethodsThis study included 88 consecutive patients (60 ± 10 years) with stable HF. LV end-diastolic and end-systolic dimensions, ejection fraction (EF), mitral and tricuspid annulus peak systolic excursion (MAPSE and TAPSE), myocardial velocities (s′, e′ and a′), LA dimensions, LA volume and LA emptying fraction were measured. A 6-min walking test (6-MWT) distance was performed on the same day of the echocardiographic examination. ResultsPatients with limited exercise performance (≤ 300 m) were older (p = 0.01), had higher NYHA functional class (p = 0.004), higher LV mass index (p = 0.003), larger LA (p = 0.002), lower LV EF (p = 0.009), larger LV end-systolic dimension (p = 0.007), higher E/A ratio (p = 0.03), reduced septal MAPSE (p < 0.001), larger LA end-systolic volume (p = 0.03), larger LA end-diastolic volume (p = 0.005) and lower LA emptying fraction (p < 0.001) compared with good performance patients. In multivariate analysis, only the LA emptying fraction [0.944 (0.898–0.993), p = 0.025] independently predicted poor exercise performance. An LA emptying fraction < 60% was 68% sensitive and 73% specific (AUC 0.73, p < 0.001) in predicting poor exercise performance. ConclusionIn heart failure patients, the impaired LA emptying function is the best predictor of poor exercise capacity. This finding highlights the need for routine LA size and function monitoring for better optimization of medical therapy in HF.

Gender and racial differences in endothelial oxidative stress and inflammation in patients with symptomatic peripheral artery disease

We compared (1) cellular reactive oxygen species (ROS) production, inflammation, and apoptosis of cultured endothelial cells treated with sera and (2) circulating inflammatory measures, antioxidant capacity, vascular biomarkers, and calf muscle hemoglobin oxygen saturation (StO2) in men and women with peripheral artery disease (PAD). A secondary aim was to compare exercise performance and daily ambulatory activity between men and women. We hypothesized that women would have more impaired endothelial cellular ROS, inflammation, and apoptosis than men as well as worse systemic inflammation, antioxidant capacity, vascular biomarkers, calf muscle StO2, exercise performance, and daily ambulatory activity. The 148 symptomatic men and women with PAD were characterized on the endothelial effects of circulating factors present in the sera by a cell culture-based bioassay on primary human arterial endothelial cells. Patients were further evaluated by circulating inflammatory and vascular biomarkers, physical examination and medical history, exercise performance, and calf muscle StO2 during exercise, and ambulatory activity was monitored during 1 week. Cellular ROS production was higher in African American women than in men (P = .021), but there was no gender difference in white individuals (P = .537). Men and women were not significantly different on endothelial cell apoptosis (P = .833) and nuclear factor κB activity (P = .465). For circulating factors, additional gender differences were found when comparisons were made within each race. In African Americans, women had higher intercellular adhesion molecule 1 (P = .022) and leptin (P < .001); whereas in white individuals, women had higher matrix metallopeptidase 9 (P = .047), higher vascular cell adhesion molecule 1 (P = .047), and lower hepatocyte growth factor (P = .046). Overall, women had higher apolipoprotein CIII (P = .035), lower pain-free distance (P = .048) and total distance (P < .001) during the 6-minute walk test, shorter time for calf muscle StO2 to reach the minimum value during exercise (P = .027), and slower average cadence (P = .004) during daily ambulation. African American women with symptomatic PAD have a heightened oxidative status, likely resulting in increased endothelial oxidative stress, compared with men. Furthermore, women exhibit a more pronounced proinflammatory profile of circulating biomarkers as well as more limited peripheral microcirculation, exercise performance, and ambulatory activity than men do. The clinical significance is that women with symptomatic PAD are in greater need than men of clinical intervention to improve oxidative stress, inflammation, and microcirculation, which may in turn have a favorable impact on their lower exercise performance and daily activity.

Predictors of exercise capacity in patients with chronic heart failure

Heart failure is a major and growing societal problem characterized by high mortality, frequent hospitalization, reduced quality of life and a complex therapeutic regimen. The six-minute walking test (6-MWT) may serve as a useful and reproducible test for assessing exercise capacity in heart failure patients and has been suggested as a simple, well-tolerated and inexpensive alternative to cardiopulmonary exercise testing (CPET). The CPET and 6-MWT are the most broadly used for assessing functional limitation in patients with heart failure. Echocardiography is well qualified to meet the growing need for noninvasive imaging in the expanding heart failure population. This study included 132 consecutive patients (61 ± 10 years, 45% women) with stable heart failure. All patients underwent 6-MWT and Doppler echocardiographic examination on the same day. Clinical, biochemical and echocardiographic predictors were analyzed to assess predictors of exercise capacity. Patients were divided into two groups based on the 6-MWT distance. The first group comprised patients with limited exercise performance (≤ 300 m), and the second group, patients with good exercise performance (>300 m). In univariate analysis, patients' age [0.931 (0.895-0.968), P < 0.001], arterial hypertension [0.481 (0.239-0.967), P = 0.040], blood urea level [0.860 (0.759-0.975), P = 0.019], New York Heart Association (NYHA) class [0.441 (0.245-0.795), P = 0.006], early diastolic E wave [1.014 (1.000-1.029), P = 0.047], total isovolumic time (t-IVT) [0.868 (0.796-0.947), P = 0.001], Tei index [0.112 (0.028-0.450), P = 0.002], and E' of left-ventricular (LV) lateral wall [1.188 (1.099-1.400), P = 0.039] independently predicted poor 6-MWT performance (<300 m). In multivariate analysis, only patients' age [0.948 (0.902-0.996), P = 0.034], arterial hypertension [0.351 (0.133-0.922), P = 0.034], and t-IVT [0.828 (0.725-0.946), P = 0.005] independently predicted poor 6-MWT performance (<300 m). In chronic stable heart failure patients, in addition to age, systemic hypertension as well as LV asynchrony, as reflected by prolonged t-IVT, are independent predictors of poor exercise capacity.

Left ventricular asynchrony and raised filling pressure predict limited exercise performance assessed by 6 minute walk test

Six minute walking test (6-MWT) may serve as a reproducible test for assessing exercise capacity in heart failure (HF) patients and can be clinically predicted. We aimed in this study to ascertain if global markers of ventricular asynchrony can predict 6MWT distance in a group of patients with HF and left ventricular (LV) ejection fraction (EF) <45%. This study included 77 consecutive patients (60 ± 12 years) with stable HF. LV end-diastolic and end-systolic dimensions, shortening fraction (SF), EF, myocardial velocities, t-IVT, and Tei index were measured, as well as 6-MWT distance. Patients with limited exercise performance (≤ 300 m) had lower SF (p = 0.02) and EF (p = 0.017), longer t-IVT (p = 0.001), higher Tei index (p = 0.002) and higher E/E' ratio (p < 0.001) compared with good performance patients. In multivariate analysis, only E/E' ratio [0.800 (0.665-0.961), p = 0.017], and t-IVT [0.769 (0.619-0.955), p = 0.018] independently predicted poor exercise performance. In heart failure patients, the higher the filling pressures and the more asynchronous the left ventricle, the poorer is the patient's exercise capacity. These findings highlight specific LV functional disturbances that should be targeted for better optimization of medical and/or electrical therapy.

Left ventricular diastolic function and exercise capacity in diabetes

To the Editor: Gusso et al. [1] have reported interesting findings regarding the impairment of stroke volume responses to submaximal exercise in female adolescent individuals with type 1 and type 2 diabetes compared with non-diabetic controls. The diabetic patients also had reduced maximal oxygen uptake. Although the pathophysiological mechanism(s) underlying the reduction in stroke volume during exercise in these young people with diabetes was outside the scope of the study, the authors suggested that increased myocardial stiffness and/or altered filling characteristics related to diabetes could have been associated with the abnormal stroke volume response and might have limited exercise performance. This is an interesting viewpoint, since whether abnormal exercise capacity is affected by well-controlled, uncomplicated diabetes per se is still a matter of debate. Diabetes has a negative impact on left ventricular (LV) diastolic function in adults [2]. Interestingly, adult patients with well-controlled, uncomplicated type 2 diabetes and left ventricular diastolic dysfunction (LVDD) have been reported to have a reduced exercise performance compared with controls [3]. Aerobic exercise training normalises LVDD and enhances maximal oxygen uptake in well-controlled, uncomplicated type 2 diabetes [4], suggesting that LVDD could negatively affect exercise performance in these patients. What happens to variables such as stroke volume and cardiac output during exercise in patients with diabetes and an abnormal LV diastolic function or LVDD is less clear. Gusso et al. [1] provide some potential pathophysiological insights that bring our understanding one step further with their results obtained during submaximal exercise. They suggest that early cardiac impairments (such as LV diastolic function-related abnormalities) could partly explain the blunted stroke volume responses to submaximal exercise while reducing exercise capacity in young female patients with diabetes. This is an appealing explanation. However, abnormalities in LV diastolic function or LVDD are also present in young and adult individuals with uncomplicated obesity [5, 6]. Even if diabetes has an independent effect on LV diastolic function in adults, it would have been interesting if Gusso et al. [1] had provided echocardiographic data as well as data on the prevalence of LVDD in each group. This would enable identification of any difference in the severity of abnormalities in LV diastolic function and in the prevalence of LVDD between groups, which could also have an impact on stroke volume. In addition, although it is difficult to evaluate the duration of diabetes precisely, especially in type 2 diabetes, disease duration could have influenced the severity of abnormalities in LV diastolic function in their diabetic groups. As highlighted by Gusso et al., the reduction in exercise capacity in their individuals with diabetes could have also been related to impairment in autonomic response to exercise limiting maximal heart rate. Since LVDD has been linked to abnormal heart rate variability in patients with type 2 diabetes Diabetologia (2009) 52:990–991 DOI 10.1007/s00125-009-1302-2

Patients After Atrial Switch Operation for Transposition of the Great Arteries Can Not Increase Stroke Volume Under Dobutamine Stress as Opposed to Patients With Congenitally Corrected Transposition

Patients after atrial switch operation for transposition of the great arteries have limited exercise performance. Rigid atrial baffles may cause a relative preload reduction. Previous studies have had suboptimal control groups, which ideally should consist of patients with congenitally corrected transposition of the great arteries (ccTGA) without previous heart surgery, having a systemic right ventricle, but lacking rigid atrial baffles. Therefore the aim of this study was to test the impact of atrial baffles by comparing 12 atrial switch patients with 11 ccTGA patients. Systemic right ventricular stroke volume (SV), heart rate, cardiac index, and other parameters were assessed during rest and dobutamine stress magnetic resonance imaging. The most important difference between the groups was that the atrial switch patients could not increase SV during stress, whereas ccTGA patients increased it significantly. There was no difference between groups in the rise of the cardiac index. Heart rate increased significantly more in atrial switch patients than in ccTGA patients. The results support the hypothesis that atrial baffles restrict a rise in SV under dobutamine stress in patients after atrial switch operation for transposition of the great arteries.

Exercise Responses Following Heart Transplantation: 5 Year Follow-Up

Heart transplantation is an established treatment for end stage heart failure. In addition to increased life expectancy, heart transplant recipients report a remarkable improvement in symptoms and functional capacity. Exercise performance following heart transplantation, however, remains impaired even in the absence of exertional symptoms. We have assessed the response to exercise in 47 patients with cardiac failure prior to and then at yearly intervals to five years post transplantation. All patients performed incremental symptom limited exercise tests during which minute ventilation (V'E), oxygen consumption (V'O2) and carbon dioxide production (V'CO2) and heart rate (HR) were measured. Ventilatory response (V'E/V'CO2), anaerobic threshold (V'O2 AT %predicted) and heart rate response (HR/VO2) were calculated. The dead space to tidal volume ratio (VD/VT) and alveolar-arterial oxygen gradient (A-aO2) were computed from transcutaneous monitoring. Despite substantial improvement in subjective functional capacity, heart transplant recipients continue to have limited exercise performance [Maximal V'O2% predicted pre-transplant 41.3 (2.2); 1 year 48.6 (1.7), p <0.001: V'O2 AT% 31.5 (1.1); 1 year 35.6 (1.0); respectively p<0.05]. The maximal oxygen uptake continued to improve at two years post-transplant but, thereafter, there was no further significant change at up to 5 years post transplant [50.9 (1.5)]. At one year post-transplantation peak HR [65.2 (0.9) vs 79.1(1.4)] and the HR/VO2 response [24.0(1.8) vs 79.6(4.2)] were significantly reduced compared to pre-transplant values. The heart rate response remained lower compared to predicted at 5 years post-transplant although there was a significant increase compared to one year post-transplant (32.9 vs 24.0mls/bt). There was a weak but significant relationship between maximal VO2 and peak HR (0.39, p<0.05) and HR/VO2 (r= 0.37, p<0.05) at one year post-transplant. Prior to transplantation the ventilatory response to exercise was elevated [V'E/V'CO2 45.6 (2.5)] and decreased significantly following transplantation [1 yr 34.1 (1.3), respectively p<0.001]. In addition, despite significant improvement in VD/VT after transplantation, it remained higher than normal [Pre VD/VT at maximum exercise 0.35 (0.02); 1 yr 0.31 (0.02); p<0.05]. There was a further fall in the VE/VCO2 and VD/VT at two years post-transplantation with no further change at up to 5 years post transplantation [VE/VCO2 32.0 (1.0); VD/VT 0.29 (0.01)]. Although cardiac output is markedly improved after transplantation, due to chronotropic incompetence associated with denervation, its response remains subnormal and this may explain the residual abnormalities of ventilatory and gas exchange responses to exercise following transplantation.

Medical management of significant coronary angiographic stenoses: outcome of 60 patients observed for 433 patient years.

Percutaneous transluminal coronary angioplasty (PTCA) has become routine in the management of patients with stable angina pectoris and significant coronary stenoses, while medical management of such patients has declined. The purpose of the present study was to evaluate the outcome of 60 patients at the Virginia Heart Institute with stable angina pectoris, observed between 1976 and 1997, who had documented evidence of severe angiographic disease but were elected to be monitored and managed in an outpatient pharmacologic rehabilitation program. Sixty patients with significant stenoses by coronary angiography (21 with single-vessel, 26 with double-vessel, and 13 with triple-vessel) without impaired ventricular function, exercise-induced ischemia or hypotension, limited exercise performance, malignant arrhythmias, or drug intolerance were enrolled in a program of pharmacologic rehabilitation and observed for an average of 7.2 years. Among the 60 patients, there were 6 deaths at a mean interval of 8.3 years. Two deaths were in patients ineligible for revascularization. Another patient who died had refused revascularization after new-onset left ventricular dysfunction, and another died intraoperatively during abdominal aortic aneurysm repair. Two patients died while exercising. Thirteen patients underwent follow-up catheterization for worsening angina; 11 of 13 showed progression, predominantly from new lesions. Four of 11 were referred for revascularization; 7 of 11 continued medical treatment; 49 patients were stable on medical therapy throughout the period of observation. Medical management of selected patients with significant coronary stenoses is safe and effective.

Decreased mechanical efficiency in clinically stable patients with COPD.

BACKGROUND: It has recently been reported that total daily energy expenditure (TDE) is increased in patients with chronic obstructive pulmonary disease (COPD) and it was hypothesised that these patients may...