PubMed Health⌕ Search

Biomedical subjects

L Vanhees

Publications and source records attributed to L Vanhees.

At least 19 recordsLinked to original sources
PubMed2006

Oxygen uptake efficiency slope in coronary artery disease: clinical use and response to training.

The Oxygen Uptake Efficiency Slope (OUES), a new parameter derived from respiratory gas analysis, has been suggested as a submaximal index of cardiopulmonary functional reserve. We evaluated the clinical application and the effect of physical training on the OUES in patients with coronary artery disease (CAD). Maximal cycle-ergometer testing with respiratory gas analysis (breath-by-breath) was performed in 590 patients with CAD and again after three months of physical training in 425 patients. OUES was determined from the linear relation of oxygen uptake (V.O (2)) vs. the logarithm of pulmonary ventilation (V (E)) during exercise, i.e. V.O (2) = a log (10) V (E) + b, where a is the OUES. The ventilatory anaerobic threshold (VAT) and the slope of the relation of V (E) nu carbon dioxide production (V.CO (2)) (V (E)-V.CO (2) slope) were also determined. Correlation coefficients of the relation from which OUES was derived in individuals averaged 0.975 +/- 0.024 (mean +/- SD) when calculated from data up to a respiratory gas exchange ratio of 1.0. Submaximal OUES was marginally lower (5.4 +/- 7.9 %, p < 0.05) than the OUES calculated from 100 % of respiratory exercise data. Of all submaximal parameters, submaximal OUES (r = 0.837, p < 0.001) and VAT (r = 0.860, p < 0.001) correlated best with peak V.O (2), followed by V (E)-V.CO (2) slope (r = - 0.469, p < 0.001). OUES was lower in patients who underwent coronary artery bypass grafting as compared with patients after coronary angioplasty (p < 0.05). Peak V.O (2) and OUES increased significantly (p < 0.001) after training with 24 +/- 19.2 % and 20.9 +/- 19.3 %, respectively. Changes in peak V.O (2) correlated better with changes in OUES and in VAT (r = 0.61 and r = 0.55, p < 0.001, respectively) than with changes in V (E)-V.CO (2) slope (r = - 0.171, p < 0.001). The submaximal OUES is clinically useful for the quantification of exercise performance and is sensitive to physical training in patients with CAD.

Coronary Artery Disease↗
PubMed2005

Changes in QRS duration are associated with maximal exercise capacity in adult patients with repaired tetralogy of Fallot.

OBJECTIVE: In adult patients with repaired tetralogy of Fallot (TF) QRS duration at rest seems to be a predictor of maximal exercise. We examined the relationship between QRS duration during exercise and exercise performance. DESIGN: In 57 consecutive TF patients QRS duration in V1 (ms) was measured at rest, at maximal exercise (Wmax, W), and at peak oxygen consumption (peak VO2, ml/min). Stroke volume (SV) was calculated from cardiac output, obtained by CO2 rebreathing. Spearman rank correlation was used to describe the relationship between QRS duration and exercise performance. Statistical significance was defined as P<0.05. RESULTS: Seven patients, who didn't pass the anaerobic threshold, and one outlier (Wmax=340 W) were excluded, resulting in a sample of 49 patients (75.5% male; median age=24 years, range 16-43 years). QRS duration at rest (median=160 ms, range 78-194 ms) and at maximal exercise (median=153 ms, range 80-193 ms) did not differ significantly. The median change of QRS duration during exercise was -5 ms (range -31 to +83 ms). This was negatively correlated with Peak VO2 (2081+/-577 ml/min; rho=-0.33, P=0.02) and Wmax (182+/-53 Watt; rho=-0.33, P=0.02). In patients with QRS shortening peak VO2 and the exercise induced increase in SV were significantly higher than in patients with QRS shortening. CONCLUSIONS: This study indicates that QRS shortening during exercise in TF patients is related with a better exercise performance. Lower increase in stroke volumes may be responsible for this difference. Further research is needed to elaborate these findings.

Adolescent↗
PubMed2003

Creatine supplementation in Huntington's disease: a placebo-controlled pilot trial.

OBJECTIVE: To evaluate the effect of creatine (Cr) supplementation (5 g/day) in Huntington's disease (HD). METHODS: A 1-year double-blind placebo-controlled study was performed in 41 patients with HD (stage I through III). At baseline and after 6 and 12 months, the functional, neuromuscular, and cognitive status of the patients was assessed by a test battery that consisted of 1) the Unified Huntington's Disease Rating Scale (UHDRS), 2) an exercise test on an isokinetic dynamometer to assess strength of the elbow flexor muscles, 3) a maximal exercise test on a bicycle ergometer to evaluate cardiorespiratory fitness, and 4) a test to assess bimanual coordination ability. Following the baseline measurements, the subjects were assigned to either a creatine (n = 26) or a placebo group (n = 15). RESULTS: Scores on the functional checklist of the UHDRS (p < 0.05), maximal static torque (p < 0.05), and peak oxygen uptake (p < 0.05) decreased from the start to the end of the study, independent of the treatment received. Cognitive functioning, bimanual coordination ability, and general motor function (total motor scale, UHDRS) did not change from baseline to 1 year in either group. CONCLUSION: One year of Cr intake, at a rate that can improve muscle functional capacity in healthy subjects and patients with neuromuscular disease (5 g/day), did not improve functional, neuromuscular, and cognitive status in patients with stage I to III HD.

Cognition↗
PubMed2003

Secondary prevention through cardiac rehabilitation: position paper of the Working Group on Cardiac Rehabilitation and Exercise Physiology of the European Society of Cardiology.

The purpose of this statement is to provide specific recommendations in regard to evaluation and intervention in each of the core components of cardiac rehabilitation (CR) to assist CR staff in the design and development of their programmes; the statement should also assist health care providers, insurers, policy makers and consumers in the recognition of the comprehensive nature of such programmes. Those charged with responsibility for secondary prevention of cardiovascular disease, whether at European, at national or at individual centre level, need to consider where and how structured programmes of CR can be delivered to the large constituency of patients now considered eligible for CR.

Europe↗
PubMed2003

High prevalence of right ventricular involvement in endurance athletes with ventricular arrhythmias. Role of an electrophysiologic study in risk stratification.

BACKGROUND: Electrocardiographic abnormalities and premature ventricular contractions are common in athletes and are generally benign. However, the specific outcome of high-level endurance athletes with frequent and complex ventricular arrhythmias is unclear. Also, information on the predictive accuracy of different investigations in this subgroup is unknown. RESULTS: We report on 46 high-level endurance athletes with ventricular arrhythmias (45 male; median age 31 years) followed-up for a median of 4.7 years. Eighty percent were cyclists. Hypertrophic cardiomyopathy or coronary abnormalities were present in < or =5%. Eighty percent of the arrhythmias had a left bundle branch morphology. Right ventricular (RV) arrhythmogenic involvement (based on a combination of multiple criteria) was manifest in 59% of the athletes, and suggestive in another 30%. Eighteen athletes developed a major arrhythmic event (sudden death in nine, all cyclists). They were significantly younger than those without event (median 23 years vs 38 years; P=0.01). Outcome could not be predicted by presenting symptoms, non-invasive arrhythmia evaluation or morphological findings at baseline. Only the induction of sustained ventricular tachycardia (VT) or ventricular fibrillation (VF) during invasive electrophysiological testing was significantly related to outcome (RR 3.4; P=0.02). Focal arrhythmias were associated with a better prognosis than those due to reentry (P=0.02) but the mechanism could be determined in only 22 (48%). CONCLUSIONS: Complex ventricular arrhythmias do not necessarily represent a benign finding in endurance athletes. An electrophysiological study is indicated for risk evaluation, both by defining inducibility and identifying the arrhythmogenic mechanism. Endurance athletes with arrhythmias have a high prevalence of right ventricular structural and/or arrhythmic involvement. Endurance sports seems to be related to the development and/or progression of the underlying arrhythmogenic substrate.

Adolescent↗
PubMed2003

Physical activity for primary and secondary prevention. Position paper of the Working Group on Cardiac Rehabilitation and Exercise Physiology of the European Society of Cardiology.

There is now clear scientific evidence linking regular aerobic physical activity to a significant cardiovascular risk reduction, and a sedentary lifestyle is currently considered one of the five major risk factors for cardiovascular disease. In the European Union, available data seem to indicate that less than 50% of the citizens are involved in regular aerobic leisure-time and/or occupational physical activity, and that the observed increasing prevalence of obesity is associated with a sedentary lifestyle. It seems reasonable therefore to provide institutions, health services, and individuals with information able to implement effective strategies for the adoption of a physically active lifestyle and for helping people to effectively incorporate physical activity into their daily life both in the primary and the secondary prevention settings. This paper summarizes the available scientific evidence dealing with the relationship between physical activity and cardiovascular health in primary and secondary prevention, and focuses on the preventive effects of aerobic physical activity, whose health benefits have been extensively documented.

Cardiovascular Diseases↗
PubMed2001

Exercise performance and training in patients with implantable cardioverter-defibrillators and coronary heart disease.

The aim of this preliminary study was to compare exercise performance and the effect of exercise training in cardiac patients with and without an implantable cardioverter-defibrillator (ICD). There are few data on exercise performance and on the effect of exercise training in patients with an ICD. Data in patients with an ICD (n = 8) were compared with those from a matched control group (n = 16). Patients performed maximal cycle-ergometer testing before and after 3 months of exercise training. All patients had to stop the exercise test for reasons of exhaustion. The predetermined heart rate threshold in ICD patients, set at the detection rate of the ICD minus 30 beats/min, was not reached. Before training, peak oxygen uptake was not different in the ICD patients compared with the control group (21.0 +/- 6.9 vs 21.9 +/- 5.0 ml oxygen standard temperature pressure dry/min/kg). Exercise training increased peak oxygen uptake to a similar extent in both groups, 20% and 24%, respectively. One ICD patient developed uneventful ventricular tachycardia at the end of the post-training exercise test, and another during training. Thus, exercise performance and the favorable response to a 3-month exercise training program are comparable in patients with ICD and matched control patients. However, tachyarrhythmias may occur during exercise testing or training and require special attention. Selected patients with ICD can be encouraged to participate in medically supervised exercise training programs. The results of this study should be confirmed with additional studies on larger numbers of subjects.

Coronary Disease↗
PubMed2000

Evaluation of the influence of cardiorespiratory fitness on diverse health risk factors, independent of waist circumference, in 40-year-old Flemish males.

OBJECTIVE: To examine whether cardiorespiratory fitness is associated with health risk factors, independent of abdominal obesity (waist circumference). RESEARCH METHODS AND PROCEDURES: Data from 141 40-year-old Flemish male subjects were used in a cross-sectional design. The main outcome measure in this study was the health risk profile, composed of lipid parameters, blood pressure, and body composition parameters. Data were analyzed by regression analysis and by means of analysis of covariance with waist circumference (WC) as covariate and cardiorespiratory fitness as source of variance. RESULTS: The data demonstrated that cardiorespiratory fitness was significantly associated with triglycerides, with the ratio of total cholesterol/serum high density lipoprotein cholesterol, and with percent body fat, independent of an association with WC. DISCUSSION: Major findings of the present cross-sectional study indicate that a high WC is associated with adverse health-related lipid profile and body composition characteristics and that relatively high levels of aerobic fitness attenuate the health risk associated with a large WC.

Adipose Tissue↗
PubMed2000

Twenty-four hour blood pressure after exercise in patients with coronary artery disease.

The objective was to assess the influence of a cardiac rehabilitation training session on blood pressure measured shortly after exercise and during the subsequent 24 h in patients with stable coronary artery disease. Blood pressure was measured conventionally and by use of 24-h ambulatory blood pressure monitoring in seven men, mean age 53+/-8 (s.d.) years, after participation in a cardiac rehabilitation session and, in randomised order, on a non-exercise control day. Conventional blood pressure averaged 112+/-7/77+/-5 mm Hg in the sitting position on the control day and was not different at the same time of the day shortly after the patients had participated in a cardiac rehabilitation training session. Standing systolic pressure was lower by 7.8+/-4.3 mm Hg (P < 0.005) after exercise compared to the control situation, but this was not associated with orthostatic symptoms. However, ambulatory monitoring showed no differences in blood pressure with the non-exercise day during the subsequent 24-h period. In conclusion, standing but not sitting blood pressure was slightly lower shortly after a cardiac rehabilitation session, but the postexercise orthostatic hypotension was not sustained during normal activities of daily living.

Blood Pressure↗
PubMed2000

Effect of bisoprolol and atenolol on endurance exercise capacity in healthy men.

OBJECTIVES: To compare the effects of a highly beta1-selective adrenoceptor antagonist bisoprolol with those of atenolol and placebo on endurance exercise capacity in young, healthy male volunteers. DESIGN: Twelve subjects randomly received oral placebo, atenolol (100 mg/day) or bisoprolol (10 mg/day) for 3 weeks, following a double-blind cross-over design. METHODS: At the end of each period, the subjects performed an endurance exercise test on the bicycle ergometer at 70% of maximal aerobic power. Cardiac output was measured by means of an automated CO2-rebreathing method. Venous blood was sampled before, during and after exercise. RESULTS: Exercise duration was not significantly different between the two drugs tested. Total exercise duration was significantly reduced by bisoprolol (-19.4 +/- 6.7%, P< 0.01) (mean +/- SEM) and by atenolol (-29.8 +/- 6.6%, P< 0.001), compared with placebo. Atenolol and bisoprolol were equally effective in lowering resting plasma renin activity, heart rate and systolic blood pressure. Resting and exercise stroke volume were significantly increased by both drugs, so that cardiac output was not significantly affected. Both drugs induced significant decreases in plasma-free fatty acid concentrations during recovery and blunted the exercise-induced increase. There were no significant relationships between the reduction of exercise duration and the haemodynamic changes or the degree of impairment of the exercise-induced increase in free fatty acid release resulting from beta-blockade. CONCLUSIONS: It is concluded that both drugs affect endurance exercise capacity in young, normotensive men, with a tendency to a smaller reduction during bisoprolol treatment. Haemodynamic variables are unlikely to be involved in the reduction of endurance exercise capacity. The role of the reduced availability of plasma free fatty acids remains unclear.

Adrenergic beta-Antagonists↗
PubMed2000

Comparison of cardiac output measured by two automated methods of CO2 rebreathing.

PURPOSE: The aim of the present study was to investigate the reproducibility of the exponential method of CO2 rebreathing with the use of automated curve fitting and to determine whether this method is superior to the equilibrium method in terms of reproducibility and clinical practicability. METHODS: Repeated measurements of cardiac output were performed using the automated equilibrium and exponential methods. These measurements were compared in 12 healthy male subjects at rest and during incremental exercise tests. RESULTS: Estimated cardiac output was not significantly different between duplicate measurements at rest nor at any level of exercise with either method. At rest the exponential method showed a tendency toward larger variability than the equilibrium method. The exponential method produced significantly higher (P < or = 0.001) estimates at rest (averaging up to 9.8 L x min(-1)) compared with the equilibrium method (averaging up to 6.5 L x min(-1)). Reproducibility improved for both methods with increasing workloads, and a second measurement at rest also seemed more reproducible and valid than the first. During exercise, both methods produced comparable values for cardiac output, and highly significant relations between cardiac output and oxygen uptake were observed for both methods (ranging from r2 = 0.79 to r2 = 0.88, P < or = 0.001). The equilibrium method produced unpleasant side effects more frequently (75% vs 21%, P < or = 0.001) compared with the exponential method and lead more subjects to premature interruption of the exercise test because of the rebreathing maneuver (42% vs 17%, P = 0.058). CONCLUSIONS: Automated curve fitting for the exponential method gave reproducible and valid results during submaximal and maximal exercise but not at rest. The equilibrium method on the other hand interfered with exercise. Therefore, the equilibrium method is recommended at rest and at lower levels of exercise and the exponential method at higher intensities.

Adolescent↗
PubMed1997

Comparison of maximum versus submaximum exercise testing in providing prognostic information after acute myocardial infarction and/or coronary artery bypass grafting.

Exercise testing after acute myocardial infarction (AMI) provides prognostic information. In many studies submaximum exercise tests performed until a given work load, metabolic equivalents (METs) level, or heart rate were used or patients discontinued the exercise test prematurely because of symptoms. We showed recently that peak oxygen uptake during maximum exercise provides independent prognostic information in patients with coronary artery disease. It is, however, not known whether maximum exercise testing is superior in predicting mortality than testing until a target level. Second, it is unclear which target end point best classifies patients at increased risk. Therefore, the independent relation between mortality and indexes of, respectively, maximum and submaximum exercise capacity, were analyzed in 527 patients, who were tested until exhaustion. To express submaximum exercise capacity dichotomous variables (the ability to reach a target METs level or not), and a continuous variable relative to maximum exercise capacity (the ventilatory anaerobic threshold) were used. After adjustment for significant covariates, peak oxygen uptake was significantly related to all-cause and cardiovascular mortality. The target level of 5 METs and the ventilatory anaerobic threshold, when expressed in absolute workload, were related to mortality when unadjusted, but after adjustment for age and other confounders significancy was lost. In multiple Cox regression analysis, the prognostic power of peak oxygen uptake remained significant when 5 METs or the anaerobic threshold were forced into the equations. When analyzing the relation of various METs levels with mortality, the 7 METs level was independently related to all-cause and cardiovascular mortality and yielded the highest diagnostic accuracy. We conclude that maximum exercise testing is more potent in predicting mortality than the ability to reach a predetermined level of exercise, such as the commonly used 5 METs level or the anaerobic threshold. Otherwise, the use of a higher target level of 7 METs is recommended.

Adult↗
PubMed1996

Effect of strength training on blood pressure measured in various conditions in sedentary men.

To examine the effect of long term strength training on heart rate and blood pressure, measured in different conditions, and on their variability, thirty healthy, previously sedentary men were randomized into a training and a control group. The strength training program consisted of 48 training sessions on a multigym apparatus at a frequency of 3 sessions each week, involving leg press, bench press, leg curl, shoulder press, leg extension and sit ups. The control group was asked not to change their sedentary lifestyle. In the subjects of the training group the load could be increased significantly for all exercises (p < 0.01). Heart rate and blood pressure were measured at rest in the supine and sitting position, during 24 hours with a non-invasive ambulatory device and during an exercise test on a cycloergometer. Repeated measures analysis of variance did not show an effect of strength training on heart rate or on blood pressure. In addition, power spectral analysis of the RR interval (ECG) and of the beat-to-beat blood pressure in the supine subject revealed similar total, low frequency and high frequency power before and after training, indicating that the neural control of both heart rate and blood pressure was not affected by a 16-week program of strength training.

Blood Pressure↗
PubMed1995

Prognostic value of training-induced change in peak exercise capacity in patients with myocardial infarcts and patients with coronary bypass surgery.

An inverse association between mortality and exercise capacity has been demonstrated previously in patients with coronary artery disease. Physical training generally increases exercise capacity. Only 1 study investigated the prognostic value of exercise capacity after training, but only in a limited number of patients. No data are available on the relation between mortality and the change in exercise performance with training. Peak oxygen uptake (VO2) was measured before and after a 3-month, predominantly dynamic training period in 417 patients with coronary artery disease. Apart from peak VO2, several patient characteristics, risk factors for cardiovascular disease, and exercise data were considered in a Cox proportional-hazards model. Peak VO2 had increased by 33% after the training period. During the total follow-up of 2,583 patient-years, 37 patients died. The cause of death was cardiovascular in 21. The prognostic value of peak VO2 was higher after training than before training, even after adjustment for age and other significant covariates. Cardiovascular mortality decreased more with greater increases in peak VO2 after training. The relative hazard rate of 0.98 indicates that a 1% greater increase in peak VO2 after training would be associated with a decrease in cardiovascular mortality of 2%. No differences in prognostic value and in training effects were observed between patients with myocardial infarcts and patients after coronary bypass grafting. Peak VO2, evaluated after a physical training program, and its change in response to training are independent predictors for cardiovascular mortality in patients with coronary artery disease.

Adult↗
PubMed1994

Prognostic significance of peak exercise capacity in patients with coronary artery disease.

OBJECTIVES: The aim of this study was to investigate the prognostic significance of peak oxygen uptake in patients with coronary artery disease who had an exercise test that could be sustained to exhaustion without limiting symptoms. BACKGROUND: Many studies have reported an inverse association between the level of exercise reached during a stress test and mortality or cardiovascular morbidity. These studies have used submaximal or symptom-limited exercise testing in patients with a recent myocardial infarction. METHODS: Peak oxygen uptake was measured in male patients > or = 4 weeks after myocardial infarction (312 patients) or coronary artery surgery (215 patients) by use of a graded uninterrupted exercise test performed to exhaustion. Apart from peak oxygen uptake, several risk factors for cardiovascular disease, patient and exercise characteristics and drug treatment were considered in the Cox proportional hazards model. RESULTS: During the total follow-up period of 3,213 patient-years, 53 patients died. Of these 53 patients, 33 died of cardiovascular causes. All-cause and cardiovascular mortality decreased with increasing peak oxygen uptake, even after adjustment for significant covariates. The relative hazard rates of 0.43 and 0.29 indicate that a hypothetic increase in peak oxygen uptake by 1 liter/min could be associated with decreases in all-cause and cardiovascular mortality of 57% and 71%, respectively. CONCLUSIONS: Exercise capacity is an independent predictor for subsequent all-cause and cardiovascular mortality in patients able to perform an exercise test until exhaustion.

Coronary Artery Bypass↗
PubMed1992

Effect of physical training on systemic and brachial artery haemodynamics in normal men.

The effect of endurance training on resting systemic and brachial haemodynamics was studied in 27 normal sedentary volunteers using a randomized cross-over design. After four months of physical training, peak oxygen uptake and physical working capacity at a heart rate of 130 beats/min (PW130) were increased by 16% (p less than 0.01) and 29% (p less than 0.001), respectively. At end-diastole left ventricular wall thickness was increased (p less than 0.01), whereas internal diameter was not changed. However, the change in internal diameter was positively related (r = 0.44, p less than 0.036) to the change in PWC130, indicating that the internal diameter increased, particularly in those subjects with the greatest increase in exercise capacity. The systemic haemodynamic adaptation to training was characterized by an increased stroke volume and concomitant reduction in heart rate so that cardiac output was not changed. On the other hand, brachial blood flow decreased by 36% on average. The change in blood flow was negatively related (r = -0.43, p = 0.03) to the change in PWC130 after training. Half the number of subjects were restudied after a four-month detraining period. The echocardiographic and Doppler variables tended to return to the pretraining level.

Adult↗