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PubMed2006

Factors affecting exercise capacity in renal transplantation candidates on continuous ambulatory peritoneal dialysis therapy.

It is well known that reduced peak oxygen uptake (peak VO2) is a predictor for mortality in several chronic diseases and during the preoperative period. The aim of this study was to investigate the factors that influence peak VO2 in renal transplant candidates receiving continuous ambulatory peritoneal dialysis (CAPD) therapy. We included 22 chronic renal failure patients (12 men, 10 women; ages 29.64 +/- 8.29 years; CAPD duration, 37.35 +/- 7.15 months) in this study. Pulmonary function tests and symptom-limited cardiopulmonary exercise tests were administered to all patients. Cardiopulmonary exercise tests were performed on a cycle ergometry at the same time of day for all patients. We analyzed the exercise duration, maximum work rate, and peak VO2 level during cycle ergometry. Serum hemoglobin, hematocrit, total cholesterol, triglyceride, blood urea nitrogen, creatinine, albumin, prealbumin, C-reactive protein, sedimentation rate, ferritin, sodium, potassium, parathyroid hormone, calcium, and phosphorus levels were analyzed from samples. Mean values of exercise duration (6.86 +/- 1.56 minutes), peak VO2 (17.20 +/- 4.91 mL/min/kg), and maximum work rate (77.09 +/- 26.09 watts) were lower when we compared them with predicted values for a healthy population. Peak VO2 was well correlated with serum phosphorus levels (4.51 +/- 1.28 mg/dL, r = .592, P = .004). Test duration was correlated with peak VO2 (r = .489, P = .025) and serum phosphorus levels (r = .530, P = .024). There were no significant correlations with other factors. As a component of ATP, phosphorus is at the hub of the energy-related mechanisms operative in muscles of the respiratory and musculoskeletal systems. Therefore, we suggest that low exercise capacity might be related to low serum phosphorus levels, and that optimal control of serum phosphorus therapy would increase exercise capacity, exercise duration, and oxygen consumption resulting in a decrease of postoperative mortality in renal transplantation candidates.

Adult↗

PubMed2002

Assessing exercise capacity, quality of life and haemodynamics in heart failure: do the tests tell us the same thing?

BACKGROUND: The objective measurement of exercise tolerance is an important component of heart failure trials. The use of laboratory-based treadmill exercise testing has attracted criticism, however, as being unrepresentative of patients' true capabilities. AIM: To examine the relationships between tests of exercise capacity, quality of life and haemodynamics in patients with stable symptomatic heart failure. METHODS: Thirty-six patients with mild-moderate chronic heart failure were studied. Exercise capacity was assessed in the laboratory by maximal treadmill tests and self-paced corridor walk tests, and in the patients' homes by hip-borne pedometers. Quality of life was assessed by a disease-specific questionnaire. Cardiac output and limb blood flow were measured by non-invasive techniques. RESULTS: Customary activity as assessed by pedometer scores correlated with quality of life questionnaire scores (r(S) = 0.47, P = 0.04), and both variables correlated with limb (calf) blood flow (pedometer scores: r(S) = 0.39, P = 0.03; quality of life scores: r(S)= 0.50, P = 0.04). The laboratory-based maximal treadmill test correlated with the self-paced corridor walk test, but neither of these tests correlated with pedometer scores, quality of life or haemodynamics. CONCLUSIONS: Different methods of assessing exercise capacity do not appear to give comparable results and bear different relationships to haemodynamic variables and quality of life. Pedometer scores of customary activity may better reflect patients' quality of life and appear to be more closely related to limb blood flow than the maximal treadmill exercise test or the corridor walk test. The sole use of laboratory-based exercise tests in therapeutic trials may give a misleading assessment of treatment efficacy in heart failure patients.

Aged↗

PubMed2005

Effects of calcium pyruvate supplementation during training on body composition, exercise capacity, and metabolic responses to exercise.

OBJECTIVE: We evaluated the effects of calcium pyruvate supplementation during training on body composition and metabolic responses to exercise. METHODS: Twenty-three untrained females were matched and assigned to ingest in a double blind and randomized manner either 5 g of calcium pyruvate (PYR) or a placebo (PL) twice daily for 30 d while participating in a supervised exercise program. Prior to and following supplementation, subjects had body composition determined via hydrodensiometry; performed a maximal cardiopulmonary exercise test; and performed a 45-min walk test at 70% of pre-training VO2 max in which fasting pre- and post exercise blood samples determined. RESULTS: No significant differences were observed between groups in energy intake or training volume. Univariate repeated measures ANOVA revealed that subjects in the PYR group gained less weight (PL 1.2 +/- 0.3, PYR 0.3 +/- 0.3 kg, P = 0.04), lost more fat (PL 1.1 +/- 0.5; PYR -0.4 +/- 0.5 kg, P = 0.03), and tended to lose a greater percentage of body fat (PL 1.0 +/- 0.7; PYR -0.65 +/- 0.6%, P = 0.07), with no differences observed in fat-free mass (PL 0.1 +/- 0.5; PYR 0.7 +/- 0.3 kg, P = 0.29). However, these changes were not significant when body composition data were analyzed by MANOVA (P = 0.16). There was some evidence that PYR may negate some of the beneficial effects of exercise on HDL values. No significant differences were observed between groups in maximal exercise responses or metabolic responses to submaximal walking. CONCLUSIONS: Results indicate that PYR supplementation during training does not significantly affect body composition or exercise performance and may negatively affect some blood lipid levels.

Adult↗

PubMed1997

[Exercise capacity and cardiovascular responses to exercise in hemiplegic patients].

We studied how the severity of hemiparesis was related to cardiovascular and metabolic responses to exercise. Eleven clinically stable patients who had had strokes were studied two to four weeks after they began walking as rehabilitation. After motor function of the lower limbs was assessed, the patients were divided into two groups according to Brunnstrom stage: one group comprised patients at stages III, IV, and V of lower limb function (n = 5), and the other comprised patients at stage VI (n = 6). A control group of 6 patients who had been hospitalized because of benign paroxysmal postural vertigo was also studied. Exercise consisted of 3-minute walks at speeds of 1.6, 3.2, and 4.8 km/hr. Blood pressure, heart rate, and the concentrations of catecholamines and of lactic acid in blood were measured before and after each stage of exercise. The double product (systolic blood pressure x heart rate) was also calculated. Changes in these variables were compared among the three groups. Increases in walking speed were associated with increases in systolic blood pressure and heart rate in hemiparetic patients, but no such changes occurred in the control group. In the patients at Brunnstrom stages III, IV, and V, the double product and the lactic acid level increased, and after the patients walked at the highest speed these were significantly higher than in the other two groups. Serum catecholamine levels did not differ among the three groups during exercise. Low intensity exercise can increase cardiovascular responses, and anaerobic metabolism can become dominant in patients with poor motor function.

Aged↗

PubMed1999

Effects of exercise training on the recovery of the autonomic nervous system and exercise capacity after acute myocardial infarction.

This study investigated the effects of aerobic exercise training on the early phase of the recovery process following acute myocardial infarction (AMI) in terms of the autonomic nervous system, cardiac function and exercise capacity. Twenty-eight patients in the first week after the onset of AMI were assigned randomly to either a training group or a control group. The training group performed aerobic exercise for 2 weeks. Cardiopulmonary exercise testing was performed 3 times during the 3 months after the onset. Heart rate variability, plasma norepinephrine (NE) levels, and cardiac index (CI) during exercise were measured. In the training group, plasma NE level and deltaCI (peak CI-rest CI) were significantly improved from 1 to 3 weeks after the onset, and the high frequency of heart rate variability and peak oxygen uptake were significantly increased up to 3 months after the onset. In the control group, the plasma NE level and the deltaCI during the 1-3 weeks post-AMI, the high frequency of heart rate variability and the peak oxygen uptake showed a tendency to improve up to 3 months after the onset. These results indicate that sympathetic nervous activity improves soon after the onset of AMI, in conjunction with improvement in cardiac function, and that this improvement is not affected by exercise training. In contrast, the recovery of parasympathetic nervous activity requires a longer period, along with the recovery of exercise capacity, which is facilitated by even short-term aerobic exercise training.

Aged↗

PubMed2006

Preserved microcirculatory response to acute estrogen not reflected by exercise capacity.

BACKGROUND: To assess the acute effect of a single dose of 10 mg oral micronized 17beta-estradiol on microcirculation in postmenopausal women with and without coronary artery disease and its potential influence on exercise capacity. METHODS: Postmenopausal women (n=11) with coronary artery disease had symptoms of ischemic heart disease and at least 1 mm ST depression at exercise. Microcirculation was examined by vital microscopy, with and without the acute administration of estrogen in a placebo-controlled cross-over design. Exercise test was performed on bicycle. The microcirculatory findings were contrasted to those in 14 healthy postmenopausal women. RESULTS: 17Beta-estradiol in serum and blood flow velocity increased significantly after acute oral estrogen administration both in women with coronary artery disease (p<0.001) and in healthy women (p<0.0001), with no significant difference between the two groups. No effect on exercise capacity or ST depression at exercise was detected. CONCLUSIONS: Previously reported data that a single dose of estrogen administered to postmenopausal women results in positive effects on exercise was not reproduced. An increased peripheral microvascular flow velocity was detected in women with coronary artery disease and this increase was not accompanied by an increased exercise capacity.

Administration, Oral↗

PubMed1994

Factor analysis of exercise capacity, dyspnoea ratings and lung function in patients with severe COPD.

In this study we aimed to determine the relationship between exercise capacity, clinical ratings of dyspnoea and lung function parameters in patients with severe chronic obstructive pulmonary disease (COPD) by means of the statistical method of factor analysis. Sixty two patients (mean age +/- SD, 66 +/- 9 yrs) in stable clinical condition, with a forced expiratory volume in one second (FEV1) < 65% of predicted were investigated. Before the study, therapy was optimized, including inhaled bronchodilators, theophylline and steroids. Exercise capacity was determined from the best 6 min walking distance achieved in five self-paced treadmill walks performed on consecutive days. Lung function testing comprised spirometry and body plethysmography. Four different tools were chosen to rate dyspnoea and quality of life: the Baseline Dyspnoea Index (BDI), the Oxygen Cost Diagram (OCD), a modified Medical Research Council (MRC) Scale, and the Chronic Respiratory Disease Questionnaire (CRQ). Principal component factor analysis revealed that the data could be reduced to three hypothetical underlying variables (factors), which accounted for 79% of the total variance. BDI, MRC, OCD, CRQ and walking distance were attributed to the first factor, forced expiratory volume in one second and airway resistance to the second factor, and lung volumes to the third factor. Thus, our data suggest that the pathophysiological condition of severe COPD is characterized by three statistically independent entities: 1) exercise capacity, dyspnoea and quality of life ratings; 2) airway obstruction; and 3) pulmonary hyperinflation.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗

PubMed2004

Exercise capacity and heart rate recovery as predictors of coronary heart disease events, in patients with heterozygous Familial Hypercholesterolemia.

BACKGROUND: Several clinical and observational studies have established that exercise capacity and activity status are strong predictors of cardiovascular and overall mortality. We aimed to evaluate the relationship between exercise tolerance test (ETT) indices and occurrence of coronary heart disease (CHD), in patients with heterozygous Familial Hypercholesterolemia (eFH). METHODS: During 1987-1997, we enrolled 639 cardiovascular disease-free patients with heterozygous eFH; 58 (9%) patients were excluded since they had a positive ETT. A fatal or non-fatal CHD event was the end point. Cox proportional hazards models were applied to evaluate the association between the investigated outcome and ETT indices. RESULTS: During the follow-up (1987-2002), 53 (18%) men and 34 (10%) women developed a CHD event (11 were fatal). The age-adjusted event rate was 87 events per 2915 person-years (3%). Statistical analysis revealed that exercise capacity (hazard ratio = 0.82, P < 0.001), heart rate recovery at 1 min (hazard ratio = 0.91, P < 0.05), and peak pulse pressure levels (hazard ratio = 1.03, P < 0.001), were predictors of CHD, after controlling for several potential confounders. CONCLUSION: Decreased exercise capacity, a delayed decrease in heart rate during the first minute of graded exercise, and increased peak pulse pressure are strong predictors of coronary events in patients with eFH. Physical activity should be strongly recommended in these patients.

Adult↗

PubMed1996

Time course of exercise capacity, skeletal and respiratory muscle performance after heart-lung transplantation.

Recipients of heart-lung transplantation (HLT) show reduced exercise capacity due to several pre- and postsurgical factors. The aim of this study was to evaluate the time course of exercise capacity, and skeletal and respiratory muscle performance in 11 patients (5 females and 6 males; age (mean +/- SD) 38 +/- 13 yrs) undergoing HLT. All of the patients were admitted to our institution for a rehabilitation programme after surgery, and were followed-up for 18 months. On admission, at discharge after an in-patient rehabilitation programme, and every 6 months, patients underwent evaluation of: lung function values; incremental treadmill exercise, 6 min walking distance (6-MWD); maximal inspiratory and expiratory pressures (MIP and MEP, respectively); and peak torque of isokinetic contraction of leg flexor and extensor muscles (IFX and IEX, respectively). On admission, patients had: reduced lung volumes as assessed by vital capacity (VC) (60 +/- 15% of predicted); reduced exercise capacity as assessed by peak oxygen consumption (V'O2,peak) (40 +/- 12% pred); reduced skeletal and respiratory muscle performance as assessed by IEX, IFX (48 +/- 16 and 28 +/- 12 Newton-metres (N x m), respectively) and by MIP and MEP (54 +/- 21 and 58 +/- 19 cmH2O, respectively). Ten patients completed the rehabilitation programme. At discharge, no significant change in dynamic and static lung volumes was observed. However, nonsignificant increases in MIP, MEP, IEX, IFX, 6-MWD and V'O2,peak were recorded. After 6 and 12 months, indices of skeletal and respiratory muscle function and V'O2, peak improved further, but still remained lower than normal values. We conclude that in patients with heart-lung transplantation, skeletal and respiratory muscle function and exercise performance are reduced after surgery, that they may improve with time but are still less than normal after 18 months.

Adult↗

PubMed2004

[Influence of myocardial mass of the univentricular heart on exercise capacity in patients with functional single ventricle and Fontan surgery].

BACKGROUND: The Fontan operation causes an acute decrease of volume overload of the univentricular heart followed by changes in ventricular geometry. The postoperative increase of myocardial mass-volume-index (MVI) may alter ventricular diastolic function. In this study, we analysed whether the increase in MVI and changes of the ventricular geometry have an effect on the decrease of the exercise capacity in patients with Fontan surgery. METHODS: We examined the cardiopulmonary function of 24 patients with functional single ventricle and Fontan operation 3.63 +/- 1.97 years after surgery (m = 14, w = 10, age: 14.57 +/- 9.74 years) using a bicycle cardiopulmonary exercise testing. The parameters of exercise capacity and cardiopulmonary function were correlated with Magnetic Resonance Imaging (MRI) parameters such as the MVI, enddiastolic ventricular muscle mass (EDMM) und endsystolic volume (ESV). RESULTS: The exercise capacity was 2.06 +/- 0.54 W/kg (60.63 +/- 15.75% of the norm) and VO(2)max was 27.41 +/- 8.87 ml/min/kg (60.91 +/- 19.7% of the norm). There was a positive correlation of exercise capacity and VO(2)max with ESV (r(2) = 0.2572, p = 0.033) and EDMM (r(2) = 0.2544, p = 0.024), but none with the MVI. CONCLUSION: Myocardial hypertrophy may influence the myocardial performance of the univentricular heart and thereby the physical performance in children and adults with Fontan circulation.

Adolescent↗

PubMed2007

Meta-analysis of the effects of respiratory rehabilitation programmes on exercise capacity in accordance with programme characteristics.

AIMS AND OBJECTIVES: This study was performed to investigate the effects of respiratory rehabilitation programmes on exercise capacity in terms of the programme type, the protocol used and other programme characteristics. BACKGROUND: As the suitable rehabilitation programmes have not been specified, diverse programmes are provided in clinics. DESIGN: Meta-analysis of the primary study results. METHODS: A computerized search through MEDLINE and CINHAL in addition to tracking down references cited in bibliographies of primarily searched studies were performed to obtain sample studies. Finally 19 research reports were examined. RESULTS: The results of meta-regression showed that the combined effect size of the programmes on exercise capacity was unaffected by forced expiratory volume (in one second), age, the duration and frequency of the programme, or study quality. In addition, the results of meta-anova indicated that the combined effect size was not affected by (i) whether a programme was hospital based or not, (ii) whether a programme was lower-extremity or combined low- and upper-extremity exercise training, (iii) measurement time, and (iv) exercise intensity. CONCLUSIONS: The effects of programmes on exercise capacity were not differed in terms of the places where rehabilitation programmes were applied, programme content, measurement time, exercise target sites of body, and the duration and frequency of the programme. RELEVANCE TO CLINICAL PRACTICE: The results of the present study can provide objective data when constructed or applied on a respiratory rehabilitation programme in clinics.

Aged↗

PubMed1983

Improved exercise capacity and differing arterial and venous tolerance during chronic isosorbide dinitrate therapy for congestive heart failure.

We studied 30 patients with moderate-to-severe congestive heart failure in a double-blind, randomized, placebo-controlled trial to determine the acute and long-term effects of isosorbide dinitrate on clinical status and on resting and exercise hemodynamics. Seventeen patients received placebo and 13 isosorbide dinitrate. First-dose isosorbide dinitrate (40 mg orally) decreased resting and exercise pulmonary capillary wedge pressure, pulmonic and systemic arterial pressures and pulmonic and systemic vascular resistances without augmenting exercise capacity. Compared with placebo, chronic therapy with isosorbide dinitrate (40 mg orally every 6 hours for 12 weeks) significantly improved clinical status and exercise capacity. Resting and exercise systemic blood pressure and systemic vascular resistance returned to baseline values during chronic isosorbide dinitrate therapy, but pulmonary capillary wedge pressure, pulmonary artery pressure and pulmonary vascular resistance remained improved. In patients with congestive heart failure, 12 weeks of oral isosorbide dinitrate therapy improves resting and exercise hemodynamics, exercise capacity, and clinical status; tolerance develops to the systemic arterial vascular effects without attenuation of the venous and pulmonary vascular effects.

Blood Pressure↗

PubMed1996

Exercise capacity of heart transplant recipients: the importance of chronotropic incompetence.

BACKGROUND: Maximal exercise capacity is limited in patients after heart transplantation. The extent to which chronotropic incompetence contributes to this intolerance has not been well defined. METHODS: This prospective cross-sectional study examined the heart rate response to exercise and its relation to exercise capacity in 159 heart transplant recipients during progressive, symptom-limited, upright exercise. All prior exercise studies of heart transplant recipients that reported peak oxygen uptake and peak heart rate were also evaluated. RESULTS: Peak oxygen uptake was closely correlated with peak heart rate (r = 0.39, p < 0.001) and maximum increase in heart rate (r = 0.49, p < 0.001) during exercise by our patients. Similar correlations were found in the published studies for peak oxygen uptake versus maximal heart rate (r = 0.54, p < 0.05) and peak oxygen uptake versus increase in heart rate (r = 0.63, p < 0.02). The current study showed that the increase in heart rate from rest to peak exercise was significantly higher and the decline in heart rate after exercise significantly faster for patients 2 or more years after transplantation than for patients less than 2 years after transplantation (46 +/- 2 versus 38 +/- 1.9 beats/min, p < 0.05); the decline in heart rate 4 minutes after exercise was 27 +/- 1.8 versus 16 +/- 1.8 beats/min, respectively ( p < 0.001). CONCLUSION: The reduction in peak oxygen consumption, particularly during the first 2 years, appears to be related in part to chronotropic incompetence. Late after transplantation the heart rate response to exercise is greater and the decline in heart rate after exercise faster, suggesting possible autonomic reinnervation in some patients. Chronotropic incompetence may be an inadequate explanation of oxygen uptake impairment seen late after transplantation, when other factors such as myocardial dysfunction and intrinsic skeletal muscle abnormalities are of increasing importance.

Analysis of Variance↗

PubMed1990

Left ventricular filling shortly after an uncomplicated myocardial infarction as a predictor of subsequent exercise capacity.

Resting measurements of left ventricular systolic function do not reliably predict exercise capacity in patients with cardiac disease. Therefore left ventricular filling shortly after a myocardial infarction was prospectively studied to determine whether it could predict subsequent exercise time. Consecutive patients with an acute infarction underwent Doppler and two-dimensional echocardiography within 36 hours of infarction. The study group was composed of the 26 men who did not have reperfusion, who had an uncomplicated myocardial infarction, and who had undergone symptom-limited stress testing during recovery (modified Bruce protocol, 44 +/- 23 days after myocardial infarction). Systolic function was measured by ejection fraction and a wall motion score. Ventricular filling was assessed by the peak transmitral Doppler velocity in early diastole (E), with atrial systole (A), their ratio (A/E), and the percentage of filling from atrial systole. The only parameter of systolic or diastolic function that correlated with exercise time was E (r = 0.65, p less than 0.001). This relationship was particularly strong for the 16 subjects taking beta blockers at the time of stress testing (r = 0.88, p less than 0.001). Stepwise multivariate regression analysis showed that only E and beta blocker therapy at the time of stress testing contributed to the model predicting recovery exercise time (R2 = 0.55). In summary, E, measured soon after an uncomplicated myocardial infarction, is one factor that predicts exercise capacity during recovery.

Coronary Circulation↗

PubMed2006

Aerobic training is safe and improves exercise capacity in patients with mitochondrial myopathy.

Exercise intolerance is a prominent symptom in patients with mitochondrial myopathy (MM), but it is still unsettled whether exercise training is safe and beneficial for patients with MM. To address this, we studied the effect of 12 weeks cycle training on exercise capacity, quality of life and underlying molecular and cellular events in five patients with single large-scale deletions, one with a microdeletion and 14 with point mutations of mitochondrial DNA (mtDNA), and 13 healthy subjects. Each training session lasted 30 min, and was performed at an intensity of 70% of VO2max (maximal oxygen uptake). Each subject performed 50 training sessions in 12 weeks. All subjects were evaluated before and after training, and 13 MM patients were studied after 8 weeks of deconditioning. Evaluation included VO2max and mutation load and mtDNA quantity, mitochondrial enzymatic activity, and number of centrally nucleated, apoptotic, ragged red and cytochrome oxidase (COX)-negative fibres in muscle biopsies from the quadriceps muscle. After 12 weeks of training, VO2max and muscle citrate synthase increased in MM (26 and 67%) and healthy (17 and 65%) subjects, while mtDNA quantity in muscle only increased in the MM patients (81%). In the MM patients, training did not change mtDNA mutation load in muscle, mitochondrial enzyme complex activities, muscle morphology and plasma creatine kinase. After deconditioning, VO2max and citrate synthase activity returned to values before training, while muscle mtDNA mutation load decreased. These findings show that aerobic training efficiently improves oxidative capacity in MM patients. Based on unchanged levels of mutant load in muscle, morphological findings on muscle biopsy and plasma creatine kinase levels during training, the treatment appears to be safe. Regular, supervised aerobic exercise is therefore recommended in MM patients with the studied mutations.

Adult↗

PubMed2003

Atriobiventricular pacing improves exercise capacity in patients with heart failure and intraventricular conduction delay.

OBJECTIVES: We sought to assess the efficacy of biventricular pacing with respect to both peak and submaximal measures of exercise in patients with New York Heart Association class III heart failure (HF) and intraventricular conduction delay in a randomized, blinded study. BACKGROUND: Submaximal and maximal changes in exercise capacity need evaluating in this patient population with this novel therapy. METHODS: Graded exercise and 6-min walk tests were performed in patients randomized to three months each of active (atrio-biventricular) and inactive pacing. Minute ventilation (VE), oxygen uptake (VO(2)), ventilated carbon dioxide (VCO(2)) and heart rate were measured in patients achieving a respiratory quotient >1 (n = 30). Oxygen pulse, anaerobic threshold (AT) and ventilatory efficiency (VE/VCO(2)) were calculated. RESULTS: Active biventricular pacing increased peak VO(2) (15.8 +/- 4.3 vs. 14.4 +/- 4.6 ml/kg/min, p = 0.02), exercise time (501 +/- 223 s vs. 437 +/- 233 s, p < 0.001) and oxygen pulse (9.3 +/- 2.8 vs. 8.1 +/- 3.1 ml/beat, p < 0.01) compared with inactive pacing. The submaximal measures of exercise capacity significantly increased with active pacing: AT (11.2 +/- 4.1 ml/kg/min vs. 9.5 +/- 2.3 ml/kg/min, p = 0.02) and 6-min walk (414 +/- 94 m vs. 359 +/- 94 m, p = 0.001). Minute ventilation/ventilated carbon dioxide improved (32 +/- 9 vs. 36 +/- 11, p = 0.03) with normalization of the VE/VCO(2) slope in 59% of patients (chi-square test, p = 0.002) with active pacing. CONCLUSIONS: Biventricular pacing may improve maximal and submaximal exercise capacity in patients with advanced HF and intraventricular conduction delay.

Adult↗

PubMed2002

Large artery stiffness: implications for exercise capacity and cardiovascular risk.

1. Large artery stiffness, or its inverse, compliance, determines pulse pressure, which, in turn, influences myocardial work capacity and coronary perfusion, both of which impact on exercise capacity and cardiovascular risk. 2. In support of a role for arterial properties in exercise performance, aerobically trained athletes (aged 30-59 years) have lower arterial stiffness than their sedentary counterparts. Furthermore, in healthy older subjects (aged 57-80 years), time to exhaustion on treadmill testing correlated positively with arterial compliance. 3. Arterial stiffness is more closely linked to exercise capacity and myocardial risk in patients with coronary disease where, independently of degree of coronary disease, those with stiffer proximal arteries have a lower exercise-induced ischaemic threshold. 4. Moderate aerobic training elevates resting arterial compliance by approximately 30%, independently of mean pressure reduction, in young healthy individuals but not in isolated systolic hypertensive patients. Rat training studies support a role for exercise training in structural remodelling of the large arteries. 5. High-resistance strength training is associated with stiffer large arteries and higher pulse pressure than matched controls. 6. Large artery stiffness is an important modulator of the myocardial blood supply and demand equation, with significant ramifications for athletic performance and ischaemic threshold in coronary disease patients. Moderate aerobic training, but not high-resistance strength training, reduces large artery stiffness in young individuals whereas older subjects with established isolated systolic hypertension are resistant to such adaptation.

Animals↗

PubMed1979

Circadian variation of exercise capacity in patients with Prinzmetal's variant angina: role of exercise-induced coronary arterial spasm.

Thirteen patients with Prinzmetal's variant angina performed treadmill exercise tests in the early morning and in the afternoon of the same day. The attacks with ST elevation were induced repeatedly in all 13 patients in the early morning, but in only two patients in the afternoon. Propranolol did not suppress the exercise-induced attacks in all 13 patients. Diltiazem suppressed the attacks in all 13 patients and phentolamine in eight of the nine patients. Coronary arteriograms demonstrated that spasm occluding completely or almost completely the large coronary artery supplying the area of myocardium showing ST elevation appeared during the attacks and disappeared along with the attacks after nitroglycerin administration in all four patients in whom the attacks were induced by arm exercise in the catheterization laboratory. We conclude that there is circadian variation of exercise capacity in patients with Prinzmetal's variant angina caused by coronary arterial spasm induced by exercise in the early morning but not in the afternoon.

Adult↗