SEARCH · PubMed Health

Results for “Exercise Tolerance”

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 1,765 records · Page 98Linked to original sources

PubMed2001

Effect of pulmonary rehabilitation on exhaled nitric oxide in patients with chronic obstructive pulmonary disease.

BACKGROUND: In patients with mild to moderate chronic obstructive pulmonary disease (COPD) the exercise induced increase in exhaled nitric oxide (eNO) parallels that observed in normal untrained subjects. There is no information on the effects of the level of exercise tolerance on eNO in these patients. The aim of this study was to evaluate the effect of a pulmonary rehabilitation programme including exercise training on eNO in patients with COPD. METHODS: In 14 consecutive male patients with stable COPD of mean (SD) age 64 (9) years and forced expiratory volume in one second (FEV1) 55 (14)% predicted, fractional eNO concentration (FeNO), peak work rate (Wpeak) and oxygen uptake (VO2peak) were assessed at baseline (T-1), at the end of a 1 month run in period (T0), and after an 8 week outpatient multidisciplinary pulmonary rehabilitation programme (T1) including cycloergometer training. RESULTS: FeNO did not significantly differ at T-1 and T0 (mean (SE) 4.3 (0.6) and 4.4 (0.6) ppb, respectively), whereas it rose significantly at T1 to 6.4 (0.7) ppb (p<0.02). Compared with T0, both Wpeak and VO2 were significantly (p<0.05) increased at T1 (mean (SE) Wpeak from 89 (5.6) W to 109 (6.9) W); VO2peak from 1.27 (0.1) l/min to 1.48 (0.1) l/min). A significant correlation was found between baseline FEV1 and the change in FeNO following the rehabilitation programme (r=-0.71; p<0.05) and between changes in FeNO and Wpeak from T0 to T1(r=0.60; p<0.05). CONCLUSIONS: Pulmonary rehabilitation in patients with mild to moderate COPD is associated with an increase in exhaled nitric oxide.

Aged↗

PubMed2004

[Relationship between Doppler indices of diastolic function and exercise capacity in patients with congestive heart failure].

UNLABELLED: Exercise intolerance is a major symptom in patients (pts) with congestive heart failure (CHF). A lack of correlation between the left ventricular systolic dysfunction and exercise capacity was found. Recently, it has been proposed that diastolic dysfunction may contribute to significant impairment of exercise tolerance in pts with CHF. The aim of the study was to compare the relationship between Doppler indices of diastolic function and exercise capacity in patients with CHF. MATERIAL AND METHODS: The study included 29 pts (20 M, 9 F) 14 with idiopathic and 15 with ischaemic cardiomyopathy. The mean left ventricular ejection fraction (LVEF) was 31 +/- 8%, VO2peak was 16.4 +/- 4.6 ml/kg/min. The mean age was 55.4 +/- 12.1, ranged from 30 to 73 years. All pts underwent complete echocardiography study. Diastolic performance was estimated using conventional Doppler mitral inflow (E, A) velocities, E/A ratio, deceleration time of E velocity (E-DT), isovolumetric relaxation time (IVRT) and color Doppler M-mode flow propagation velocity (Vp). Resting spirometry and cardiopulmonary exercise test (CPX) were performed in all pts. Exercise capacity was measured as oxygen consumption at peak exercise (VO2peak). The association between echocardiography parameters and VO2peak was evaluated by Spearman's correlation coefficients (r). RESULTS: We found that VO2peak correlated significantly with the LV filling pattern estimated by the transmitral Doppler E/A ratio (r=-0.4, p=0.03), A-wave velocity (r=0.4, p=0.03) and velocity flow propagation (r=0.4, p=0.05). There was no correlation between VO2peak and following mitral inflow parameters: (E-wave, DT, IVRT). There was no correlation between VO2peak and LVEF. CONCLUSIONS: 1. Doppler indices of diastolic function are important determinants of exercise capacity in CHF pts. 2. Assessment of transmitral flow velocities holds a substantial diagnostic potential, which may be utilized in everyday clinical practice as a alternative in routine monitoring of systolic heart failure.

Adult↗

PubMed1979

Exercise ECG in evaluation of aortocoronary bypass surgery; report on 66 patients.

To evaluate the relationship of functional results after aortocoronary saphenous bypass surgery, 66 patients of age 33--65 yr (mean 52) underwent a standarized bicycle exercise test before and an average of 14 mth after operation. Capacity of exercise was correlated with symptomatic response and graft patency. Group exercise tolerance was significantly improved after operation, and was about 60% of that of a population-based series of 52-yr-old men [6]. After operation 74% of the patients could exercise to fatigue without apparent limiting cardiac symptoms, while 26% still were incapacitated because of angina. Improvement in tolerance for exercise correlated with symptomatic improvement as well as patency of the grafts; patients with no grafts remaining patent showed no improvement in exercise performance.

Adult↗

PubMed2006

Exercise capacity and impact of exercise training in patients after a Fontan procedure: a review.

After a successful Fontan procedure, children and adolescents should improve their exercise capacity. However, several studies have shown that these children have a reduced maximal oxygen consumption compared with healthy children. The lower exercise performance in these patients was mainly explained by a reduced cardiorespiratory functional capacity. However, it has recently been reported that the lower exercise performance may also be related to altered skeletal muscle function. Moreover, exercise training had a beneficial impact on several parameters related to exercise tolerance in these patients. The main studies supporting these observations are reviewed, with a focus on the physiological adaptation and limitation of the exercise performance as well as the benefits of exercise training in patients after a Fontan procedure.

Adaptation, Physiological↗

PubMed1994

The role of cardiopulmonary exercise testing in lung and heart-lung transplantation.

Cardiopulmonary exercise testing in recipients of lung and heart-lung transplants demonstrates significant restoration of exercise tolerance to individuals severely disabled by their underlying cardiopulmonary disease. Recipients can perform moderate levels of activity compatible with a normal lifestyle. Considerable exercise limitation, however, remains in most recipients as measured by maximum oxygen uptake and work rate, despite substantial improvement and often normalization in resting cardiopulmonary function. The amount of exercise limitation observed in recipients of single-lung, bilateral-lung, and heart-lung transplants is interestingly similar, and the pattern of limitation is somewhat stereotyped. Ventilatory abnormalities are never limiting. Gas exchange abnormalities are sometimes seen (especially in single-lung transplant recipients) but generally are not limiting. Cardiac dysfunction is sometimes seen (particularly in heart-lung transplant recipients) but also does not appear to be limiting. Peripheral factors limiting exercise (which may include abnormalities in the peripheral circulation and peripheral neuromuscular structure and function) are almost universally seen and are probably the primary determinant of exercise limitation in these patients. At present, the relative contributions of various peripheral factors to exercise limitation are unclear. Further study may help elucidate these issues.

Disability Evaluation↗

PubMed1983

Pindolol and propranolol in patients with angina pectoris and normal or near-normal ventricular function. Lack of influence of intrinsic sympathomimetic activity on global and segmental left ventricular function assessed by radionuclide ventriculography.

To investigate the role of intrinsic sympathomimetic activity on left ventricular (LV) function during antianginal therapy with beta-adrenoreceptor antagonists, 23 patients with chronic, exercise-induced angina pectoris and normal or near normal LV function underwent radionuclide ventriculography at rest and during exercise, during 3 randomly allocated periods: (a) treatment with oral propranolol, a drug without intrinsic sympathomimetic activity, 40 to 80 mg 4 times a day; (2) treatment with pindolol, a drug with marked intrinsic sympathomimetic activity, 5 to 10 mg 2 times a day; and (3) a control period. During the control period, the LV ejection fraction decreased from rest (58.9 +/- 8.2%) to exercise (54.3 +/- 10.7%), and the wall motion score decreased from 0.57 +/- 1.08 at rest to 2.39 +/- 2.10 during exercise, p less than 0.001. After propranolol, the ejection fraction did not change significantly at rest (57.2 +/- 8.1%) but improved during exercise (56.8 +/- 11.8%), compared with control values. After pindolol, the ejection fraction did not change at rest (57.9 +/- 8.6%) but improved during exercise (56.9 +/- 8.1%), compared with control values. Similarly, the wall motion score after administration of both agents did not change significantly at rest, but improved during exercise (p less than 0.001). The number of anginal episodes, nitroglycerin tablets consumed, and magnitude of S-T segment depression decreased significantly with both pindolol and propranolol. With both drugs, a similar improvement in exercise tolerance and a similar decrease in exercise heart rate and blood pressure were obtained. It is concluded that pindolol and propranolol, beta-adrenoreceptor antagonists with and without intrinsic sympathomimetic activity, respectively, have similar effects on global and regional LV function in patients with angina pectoris, at doses producing equal suppression of exercise heart rate and similar antianginal effect.

Adult↗

PubMed1984

Effects of captopril on abnormalities of the peripheral circulation and respiratory function in patients with severe heart failure.

Limb blood flow and respiratory function were compared in ten patients with severe heart failure inadequately controlled by diuretics and normal control subjects matched for age and sex. Both forearm and calf blood flow, at rest and after exercise, were lower in the patients than in the control subjects. Oxygen consumption during submaximal exercise was also lower in the patients and minute ventilation was higher. Captopril, administered in a single-blind controlled study to the patients, resulted in an improvement in these abnormalities, with the exception of oxygen consumption. It also improved exercise tolerance and reduced perceived exertion during exercise. Captopril is effective treatment for severe heart failure and improves some of the peripheral haemodynamic and respiratory abnormalities.

Acute Disease↗

PubMed1983

Right bundle branch block: long-term prognosis in apparently healthy men.

The long-term cardiac prognosis of 24 clinically healthy men with complete right bundle branch block, identified from the 1,142 men constituting the population of the Baltimore Longitudinal Study on Aging, was assessed over a follow-up period averaging 8.4 years. When compared with a control group matched for age at which right bundle branch block appeared (mean +/- standard deviation 64.0 +/- 13.5 years), men with right bundle branch block showed no difference in the prevalence of antecedent coronary risk factors or obstructive lung disease. The incidence of angina pectoris, myocardial infarction, valvular heart disease, cardiomegaly, congestive heart failure, advanced heart block or cardiac death in these men did not differ from that of the control group over the observation period. Furthermore, at the latest follow-up study, maximal aerobic exercise tolerance and chronotropic response to maximal exercise were not impaired in men with right bundle branch block relative to control men (9.1 +/- 2.2 versus 7.3 +/- 3.0 minutes and 150.3 +/- 23.5 versus 147.7 +/- 20.7 beats/minute, respectively). However, axis deviation leftward of -30 degrees was present in 46% of men with right bundle branch block but in only 15% of control subjects at latest follow-up (probability [p] less than 0.01). Although the PR interval lengthened by 40 ms or more developed in only 6% of control subjects over the observation period, such prolongation occurred in 29% of men with right bundle branch block (p less than 0.05). These results support the concept that right bundle branch block in these asymptomatic men is a manifestation of a primary abnormality of the cardiac conduction system but has no demonstrable adverse effect on long-term cardiac morbidity or mortality.

Aged↗

PubMed1999

Visceral protein status and caloric intake in exercising versus nonexercising individuals with end-stage renal disease.

OBJECTIVE: To determine if differences exist in kilocalorie and protein intake and visceral protein levels for patients with End-Stage Renal Disease (ESRD) exercising during dialysis versus not exercising. DESIGN: Prospective study of 11 patients with ESRD over a study period of 12 weeks. SETTING: Outpatient renal dialysis clinic. PATIENTS: Patients with ESRD undergoing hemodialysis (HD) three times weekly who met the following criteria were selected: aged 25 to 65 years, nondiabetic, no current physical activity, blood pressure of 160/95 mm Hg or less at the second hour of HD, no unstable angina pectoris. Eleven patients who met the criteria were randomized into two groups; five patients with exercise (E) and six patients without exercise (NE). INTERVENTIONS: From weeks 5 to 8, E patients began exercise during HD three times a week. Exercise gradually increased by 3 minutes each dialysis day, maintaining 60% to 80% maximal heart rate (HR). By the end of week 8, all E patients reached 45 minutes of exercise, including 5 minutes each of warm-up and cooldown. Patients continued 45 minutes of exercise each dialysis day during HD at 60% to 80% maximal HR during weeks 9 through 12. NE patients remained sedentary throughout the study. MAIN OUTCOME MEASURE: Twenty-four-hour dietary recalls were obtained weekly for the 12 weeks from all patients for kilocalorie and protein intake. Serum levels of prealbumin, transferrin, and predialysis and postdialysis albumin were obtained immediately before the study onset and at weeks 4, 8, and 12. Comments related to patients' feelings and exercise were recorded but not analyzed statistically. RESULTS: Analysis of covariance for repeated measures for kilocalories yielded no significance by group or over time. Mean intakes for E patients for weeks 9 through 12 were clinically greater than weeks 1 through 8 by approximately 200 kilocalories. The mean protein intake for E patients at weeks 9 through 12 (79 +/- 41 g) appeared clinically greater than NE patients at weeks 9 through 12 (58 +/- 11 g), although not statistically different. Adequacy of dialysis (Kt/V) and initial levels of each serum protein were covariates for analysis of variance. No statistical differences were found for prealbumin levels. Transferrin levels were within normal ranges but differed (P <.05) by group (E or NE) and time periods. Prealbumin and postalbumin concentrations ranged from slightly low to adequate levels and were different over time (P <. 05). CONCLUSION: Kilocalorie and protein intakes appeared to increase for E patients during the exercise program. No consistent increases of visceral proteins were found for E patients. A majority of E patients expressed feelings of improved health, better exercise tolerance, and improved appetite and viewed exercise as enjoyable.

Adult↗

PubMed2001

Effects of short-term PAP treatment on endurance exercise performance in obstructive sleep apnea patients.

Objective: To measure the effects of 4 weeks of nasal positive airway pressure therapy (PAP) on exercise performance in obstructive sleep apnea patients (OSA).Background: Little published research is available which describes the effects of OSA on exercise tolerance or upon the potential of exercise testing to evaluate the outcomes of PAP therapy.Methods: Exercise testing was performed on an electronic cycle ergometer with continuous ramping to allow collection of numerous data points for each subject, up to a vigorous terminal intensity. Linear regression established each subject's pre-treatment scores for the dependent variables at 60% of estimated peak power (W(60%)). Responses at the pre-treatment W(60%) test were used to quantify and compare to responses at the same power output after treatment.Results: OSA by nocturnal polysomnography was moderately severe in this group; the respiratory distress index was 48+/-22 (mean+/-SD; n=9). Exercise heart rates after PAP therapy averaged 10.2 bt/min less at W(60%) (P<0.05). Other variables were lower but non-significantly so, further suggesting a lower cardiorespiratory exercise demand after treatment, i.e. oxygen consumption ( downward arrow7.6%), and Rating of Perceived Exertion ( downward arrow8.8%).Conclusion: Brief treatment with PAP therapy improves objective markers of aerobic exercise performance.

Journal Article↗

PubMed1987

Acute and chronic effects of molsidomine on pulmonary artery pressure and work capacity in patients with coronary heart disease.

To test the clinically supposed development of tolerance during chronic molsidomine therapy we studied a total of 11 patients with angiographically-proven coronary heart disease at rest and during ergometric exercise (supine position; submaximal, i.e. 50 W for 3 min, and maximal exercise). Pulmonary arterial pressure (PAPmean, floating catheter), arterial blood pressure (RR, cuff method), work capacity (W x min) and duration of exercise loading (sec) were measured at rest and on exercise before and during chronic (4 weeks) oral therapy with 3 x 4 mg day-1 of molsidomine. Acute administration of 4 mg molsidomine reduced the mean arterial resting pressure by 12% and under submaximal exercise loading by 8%. After molsidomine, the PAPmean was reduced by 35% at rest; following a period of treatment of 4 weeks no significant decrease in efficacy could be discerned (PAPmean reduction by 31%). Under submaximal and maximal exercise the PAPmean dropped by 44% and 37%, respectively (35.5 +/- 6.7 cf. 19.9 +/- 4.5 mmHg; 39.2 +/- 6.5 cf. 24.8 +/- 7.0 mmHg), whilst simultaneously the work capacity increased by 93% (281 +/- 108 cf. 545 +/- 254 W x min). After 4 weeks treatment with 12 mg day-1 of molsidomine, the PAPmean of 22.4 +/- 6.6 mmHg and 30.1 +/- 9.9 mmHg under identical exercise loading conditions, remained significantly below the exercise load value prior to the onset of medication. The molsidomine-induced increase in the exercise tolerance was maintained throughout the long-term medication (537 +/- 268 W x min). With a four-week treatment with daily doses of molsidomine there was a persistent effect on the pulmonary arterial pressure and the work capacity. Thus development of tolerance during high dose, long-term molsidomine therapy is not to be expected.

Adult↗

PubMed1996

Role of exercise in the evaluation and management of pulmonary disease in children and youth.

Asthma is the most common chronic pulmonary disorder affecting children in the U.S. Cystic fibrosis is the most common life-shortening inherited disease affecting white populations. With both disorders, children may have impaired exercise tolerance and abnormal cardiopulmonary responses to exercise. Exercise testing can aid in the diagnosis of exercise-induced asthma, and in determining prognosis in cystic fibrosis. Children with asthma and cystic fibrosis have been shown to benefit from exercise training, mainly through improved aerobic fitness and cardiopulmonary efficiency. In summary, exercise plays a valuable role in the evaluation and management of children with asthma and cystic fibrosis.

Adolescent↗

PubMed2002

Chest pain unit management of patients at low and not low-risk for coronary artery disease in the emergency department. A 5-year experience in the Florence area.

In this study, we screened a total of 6723 consecutive patients with chest pain and ECG non-diagnostic for acute myocardial infarction (AMI) on presentation to the emergency department (ED). The aim of the study was to avoid missed AMI, improve safe early discharge and reduce inappropriate coronary care unit (CCU) admission. Chest pain patients were triaged using a clinical chest pain score and managed in a chest pain unit (CPU). Patients with a low clinical chest pain score were considered at very 'low-risk' for cardiovascular events and discharged from the ED; patients with a high chest pain score were submitted to CPU management. Observation and titration of serum markers of myocardial injury were obtained up to 6 hours. Rest or stress myocardial scintigraphy (SPECT) was performed in patients > 40 years or with > or = 2 major coronary risk factors. Exercise Tolerance Test (ETT) or Stress-Echocardiogram (stress-Echo) were performed in younger patients or with < 2 coronary risk factor, or unable to exercise, respectively We discharged directly from the ED the majority of patients (4454; 66%): in this group there was only a 0.2% final diagnosis of coronary artery disease (CAD) at follow-up. The remaining 34% of patients, with non-diagnostic or normal ECG, were managed in the CPU. In this group, 1487 patients (representing 22% of the overall study group) were found positive for CAD, two-thirds because of delayed ECG or serum markers of myocardial injury, and one-third by Echo, SPECT or ETT. In conclusion, CPU based management allowed 22% early detection of myocardial ischaemia and 78% early discharge from the ED avoiding inappropriate CCU admission and optimizing the use of urgent angiography.

Aged↗

PubMed1986

Mitral regurgitation: relationship of noninvasive descriptors of right and left ventricular performance to clinical and hemodynamic findings and to prognosis in medically and surgically treated patients.

To determine objective predictors of survival, 53 patients with chronic, hemodynamically severe mitral regurgitation underwent rest and exercise radionuclide cineangiography, echocardiography, treadmill exercise testing, and ambulatory electrocardiographic monitoring before prospective (average 30 month) follow-up. At entry, symptom status correlated best with radionuclide-based right ventricular ejection fraction (RVEF) and left atrial size, while treadmill exercise tolerance correlated best with RVEF during exercise (r = .48, p less than .005). Correspondingly, in 23 patients who underwent cardiac catheterization, pulmonary arterial systolic and wedge pressures were significantly inversely related to RVEF. On the 24 hr ambulatory electrocardiogram, nonsustained ventricular tachycardia was present in 29% of patients, most frequently when both RVEF and left ventricular ejection fraction (LVEF) were subnormal (p = .03 vs other patients). Since entry, 35 patients have been managed without surgery for 9 to 57 months (average 28); three of these who subsequently underwent operation also are among the 21 patients who have undergone mitral valve replacement (MVR). During the average 28 months of observation under medical treatment five of 35 nonoperated patients have died; all five were among the six nonoperated patients with RVEFs of 30% or less at entry, a descriptor that significantly identified those at high mortality risk (p less than .0001 vs patients with RVEFs greater than 30%). All five also were among the eight nonoperated patients with LVEFs of 45% or less (lower limit of normal), a descriptor that also significantly predicted mortality. Three of the 21 patients who underwent surgery have died, all late after MVR. Among operated patients, only age was a predictor of postoperative survival. A trend toward improved survival was found in the patients with depressed right or left ventricular ejection fraction who underwent surgery compared with those who did not.

Actuarial Analysis↗

PubMed2005

An evaluation of the acute impact of pursed lips breathing on walking distance in nonspontaneous pursed lips breathing chronic obstructive pulmonary disease patients.

This study was designed to test the effects of pursed lips breathing (PLB) during exercise in patients with chronic obstructive pulmonary disease (COPD) who did not spontaneously perform PLB. Sixty-nine COPD patients, mean FEV1 (SD) 1.09 (0.5), age 68 (51-83) were recruited to the study. They performed three incremental shuttle walk tests (ISWT). The first walk was designed to identify natural PLBs and the next two walks were performed in a random order; ISWT + PLB or ISWT whilst breathing normally. Measures of respiratory rate (RR), breathlessness and oxygen saturation were taken before and after walks. Data was analysed using the t-test. Fifteen patients demonstrated PLB on baseline ISWT and were therefore excluded from further walking tests although baseline data was included in the analysis. There was no significant difference between walks, mean (SD), 298.5 (173.7) PLB and non-PLB; 292.5 (161.9) nor any difference in dyspnoea. There was a significant reduction in end exercise RR and recovery time with PLB, mean difference (95% CI); 6.2 (4.5-7.9) and 24.9 (2.8-47.0) seconds, respectively. Patients who showed a good response with the PLB walk (41%) had significantly higher baseline breathlessness, Borg score, mean (SD), 1.5 (1.0) versus 0.74 (0.96) (P = 0.02). Natural PLB patients demonstrated lower exercise tolerance on the baseline walk (P = 0.01) and a trend towards greater resting breathlessness than those who did not. This study shows PLB during exercise and recovery results in lower post exercise RR and speeds return to pre exercise breathlessness, compared with exercise and non-PLB. Reductions in RR appear to be greatest in those patients with resting breathlessness.

Aged↗

PubMed1982

Clinical evaluation of left ventricular performance in patients with myocardial infarction: comparison of hemodynamic responses to exercise and angiographic findings.

In order to evaluate the left ventricular performance during exercise in patients with myocardial infarction, we performed a symptom-limited multistage exercise test using a bicycle ergometer in the supine position on 82 patients with myocardial infarction, and their hemodynamic responses to exercise were analyzed. Patients were subdivided into three groups according to the levels of pulmonary capillary wedge pressure (PCWP) and cardiac index (CI) obtained at the end-point of the exercise: Group I (20 patients) with PCWP less than 18 mmHg and CI greater than or equal to 5.0 L/min/m2; Group II (32 patients) with PCWP greater than or equal to 18 mmHg and CI greater than or equal to 5.0 L/min/m2; Group III (30 patients) with PCWP greater than or equal to 18 mmHg and CI less than 5.0 L/min/m2. Exercise tolerance expressed as the duration of exercise was 11.9 +/- 0.5 (SEM) min in Group I, 10.6 +/- 0.4 in Group II and 7.8 +/- 0.5 in Group III, which was closely correlated with the left ventricular function observed at the end-point of the exercise. During exercise stroke volume index (SVI) decreased slightly in Group III, while it increased significantly in Groups I and II. The extent of coronary artery lesion in Group III was more severe than in Groups I and II. In 50 patients without prior myocardial infarction, infarct size estimated by total released CPK was larger in Group III than in Group I. These findings indicate that coronary artery lesion and infarct size are important factors contributing to left ventricular performance during exercise in patients with myocardial infarction.

Adult↗

PubMed1998

Calcium sensitising agents in heart failure.

Congestive heart failure (CHF) is a common cardiovascular disorder that is characterised, in part, by a decreased cardiac output reserve. Accordingly, there is ongoing interest in the role of positive inotropic agents (e.g. adrenergic agonists and phosphodiesterase type III inhibitors, which mediate their cardiovascular effects via a cyclic adenosine monophosphate-dependent mechanism) in the treatment of CHF. However, enthusiasm for positive inotropic therapy in CHF has been dampened by the results of clinical trials, which have shown that these drugs are associated with an increased risk of mortality. Calcium sensitising agents are a heterogeneous group of positive inotropic agents that mediate their cardiovascular actions (at least in part) by increasing the sensitivity of the contractile elements to calcium. Increased sensitivity to calcium may be related to changes in calcium binding to troponin C, or to direct effects on the actin-myosin complex. In addition, the inhibition of phosphodiesterase type III may contribute to the positive inotropic action of calcium sensitising agents. Five agents with calcium sensitising properties (pimobendan, levosimendan, MCI-154, EMD-53998 and CGP-48506) have been studied as possible therapies for CHF. All of these agents have demonstrated a positive inotropic action in isolated cardiac tissue and in animal models of CHF. In clinical trials, pimobendan, the most extensively studied of these drugs, was well tolerated and was associated with improved exercise tolerance during the first 6 months of therapy; however, it was also associated with a nonsignificant trend towards increased mortality. Because many of the calcium sensitising agents also inhibit phosphodiesterase type III activity, the long term safety of these agents is uncertain. Large-scale survival trials are required to determine the long term safety and efficacy of these agents before their role in the treatment of CHF can be defined.

Aged↗

PubMed2000

General practitioners' beliefs, attitudes and reported actions towards chronic fatigue syndrome.

OBJECTIVE: To undertake a survey of Australian general practitioners (GPs) to explore their beliefs, attitudes and reported actions with respect to chronic fatigue syndrome (CFS). METHOD: A random sample of 2090 Australian GPs, stratified by state, was surveyed in May-August 1995. RESULTS: A 77% response rate was obtained. For the majority of practitioners who pursue a diagnosis of CFS, six symptoms were considered to be of significance: chronic unremitting fatigue for over 6 months; failure to recover energy after rest; reduced exercise tolerance; prostration for several days after exercise; generalised myalgia and poor concentration. Individual counselling was the most frequently used treatment. Thirty-one percent of practitioners reported that they did not believe that CFS is a distinct syndrome. Of these, 70% reported that the most likely cause of chronic fatigue was depression. CONCLUSION: There is considerable diversity of opinion between practitioners about CFS. The diversity extends from questioning whether the syndrome even exists to different strategies for diagnosis and management.

Adult↗