Beta-adrenergic blockade and metabo-chemoreflex contributions to exercise capacity.

Purpose: Exercise-induced dyspnea in patients with cardiopulmonary diseases may be related to sympathetic nervous system activation, with increased metabo- and/or chemosensitivities. Whether this mechanism plays a role in exercising normal subjects remains unclear.

Methods: Muscle sympathetic nerve activity (MSNA), HR, ventilation (V(E)), O2 saturation (SpO2), and end-tidal PCO2 (PetCO2) were measured in 14 healthy young adults after 1 wk of beta1-receptor blockade with bisoprolol 5 mg x d(-1) versus placebo after a double-blind, placebo-controlled, randomized crossover design.

Physiological response to the six-minute walk test in pulmonary arterial hypertension.

The 6-min walk test (6MWT) is commonly used to evaluate exercise capacity in patients with pulmonary arterial hypertension (PAH). However, little is known about the corresponding metabolic stress as measured by cardiopulmonary exercise testing. The present study, therefore, measured ventilatory variables and heart rate during the 6MWT and symptom-limited incremental maximal exercise testing in 20 patients with PAH.

The effect of different intensity modalities of resistance training on beat-to-beat blood pressure in cardiac patients.

Background: Resistance training has been introduced in cardiac rehabilitation to give more benefit than traditional training. Haemodynamic evaluation of cardiac patients to resistance training has generally consisted of continuous HR monitoring and discontinuous blood pressure measurements.

Design And Methods: Blood pressure (BP) and heart rate (HR) responses to resistance training were evaluated using continuous monitoring (Finapres) during low (four sets of 17 repetitions at 40% of the one-repetition maximum strength [1-RM]) and high intensity resistance training (four sets of 10 repetitions at 70% of 1-RM) on a leg extension machine in 14 patients who participated in a rehabilitation programme.

Exercise testing in pulmonary arterial hypertension and in chronic heart failure.

Exercise capacity is reduced in pulmonary arterial hypertension and in chronic left heart failure, but it is not known whether the cardiopulmonary exercise testing profile is different in the two conditions at the same severity of functional limitation. Nineteen patients with pulmonary arterial hypertension and 19 with chronic heart failure underwent a 6-min walk test and symptom-limited maximal incremental cycle ergometry. The patients with pulmonary arterial hypertension and chronic heart failure did not differ in New York Heart Association Functional Class (mean +/- SEM 2.

[The heart surgery department].

The initial development of cardiac surgery at Erasme Hospital was closely related to the achievements in thoracic organ transplantation, with numerous synergies between other clinical and research units of the Faculty of Medicine. New advances in biology and biotechnology have met the challenges of modern cardiology, in the fields of advanced heart failure, refractory angina, rhythm disturbances or minimally invasive surgery. Fundamental aspects of clinical practice have been the subject of laboratory investigations, resulting in fruitful interactions and promising scientific outlooks.

Haemodynamic response to dynamic exercise after heart-lung transplantation.

The purpose of this study was to investigate the haemodynamic response to dynamic exercise after heart-lung transplantation (HLT). Nine stable HLT recipients (6 males) were studied 12-55 months after transplantation. While sitting on a cycle ergometer, they first underwent a maximal symptom-limited exercise test (power increment was 10 W x min(-1)) to determine the maximal tolerable workload.

Renal responses to exercise in heart and kidney transplant patients.

There is a lack of information about renal responses in heart and kidney transplant patients after intense physical exercise. Eleven heart and ten kidney transplant recipients, as well as two control groups of healthy subjects, were given a maximum exercise test on a bicycle ergometer. One control group was also given a moderate load corresponding to the peak load of the kidney transplant group.

Long-term follow-up of heart transplant patients.

The present study was designated to assess long term functional capacity, blood pressure and renal function at 12 and 60 months after heart transplantation. The data of sixty heart transplant recipients were retrospectively reviewed. At rest, radionuclide ejection fraction and cardiac index measured by thermodilution were within normal range, demonstrating normal left systolic function.

Does cardiac denervation affect the short-term blood pressure variability in humans?

Objective: To explore the repercussion of cardiac denervation on the short-term blood pressure variability in humans, in order to assess the extent to which the variability of blood pressure is linked to the variability of heart rate.

Methods: Beat-to-beat blood pressure and RR interval time were recorded in 16 heart-transplanted patients and were compared with those of 10 healthy control subjects in the resting supine, sitting and standing positions. Blood pressure and RR interval variabilities were assessed by spectral analysis.

Respiratory dysfunction in congestive heart failure: correction after heart transplantation.

Severe chronic congestive heart failure (CCHF) is known to induce a restrictive ventilatory defect, with a small decrease in lung transfer factor for carbon monoxide (TLCO). The aim of the present work was to assess the reversibility of this dysfunction. We studied a group of 47 patients with CCHF, before and one year after heart transplantation.

Mechanisms of improved arterial oxygenation after peripheral chemoreceptor stimulation during hypoxic exercise.

Almitrine, a peripheral chemoreceptor agonist, has been reported to increase arterial O2 saturation (SaO2) without changing minute ventilation (VE) during hypoxic exercise (Giesbrecht et al. J. Appl.

Relationship of middle cerebral artery blood flow velocity to intensity during dynamic exercise in normal subjects.

Cerebral blood flow has been reported to increase during dynamic exercise, but whether this occurs in proportion to the intensity remains unsettled. We measured middle cerebral artery blood flow velocity (vm) by transcranial Doppler ultrasound in 14 healthy young adults, at rest and during dynamic exercise performed on a cycle ergometer at a intensity progressively increasing, by 50 W every 4 min until exhaustion. Arterial blood pressure, heart rate, end-tidal, partial pressure of carbon dioxide (PETCO2), oxygen uptake (VO2) and carbon dioxide output were determined at exercise intensity.

Exercise and heart transplantation. A review.

Results of heart transplantation as therapy for end-stage cardiac diseases are encouraging not only because of actuarial survival curves but also because of the recovered quality of life for the heart transplant recipient. Although heart transplantation drastically improves the physical capacity of the patients, heart recipients still have a reduced maximal aerobic capacity compared to healthy people. Altered resting and exercise haemodynamics, due to cardiac denervation, are a common finding after orthotopic heart transplantation: increases in heart rate and stroke volume at exercise are first linked with the augmented venous return and later with the increased plasmatic nor-adrenaline level.

Increased platelet aggregability and prostacyclin biosynthesis induced by intense physical exercise.

Changes in platelet aggregability during maximal bicycle ergometry were studied in healthy untrained subjects. Ex vivo platelet aggregation in response to ADP and collagen was measured in whole blood by impedance aggregometry or by direct electronic counting in an Ultra-Flo 100 platelet counter. This last method revealed that the platelet aggregation induced by low concentration of ADP (0.

[Functional non-invasive cardio-respiratory evaluation a month and a year after orthotopic heart transplantation].

Cardio-respiratory stress tests of 14 patients, performed one month and one year after orthotopic heart transplant, are compared in order to demonstrate the functional and metabolic improvements of their adaptation to stress. At maximal stress, we note a 33 p. cent increase of the oxygen consumption (p 0.

Psychosocial and physical rehabilitation after heart transplantation: 1-year follow-up.

Experience on the rehabilitation of 62 heart-transplanted patients with a mean follow-up period of 15 months and a total survival rate of 79% is reported. From the present study we may conclude that: (a) One month after surgery, oxygen consumption of transplanted patients compared to coronary artery bypass-grafted patients was statistically lower (p less than 0.025).

[Early exercise test after revascularization and rehabilitation].

Ergospirometry was performed on 51 patients before their discharge from hospital, that is between the seventh and tenth days after myocardial revascularization by cardiac bypass surgery. The aim of our study is to show that this type of measurement can be performed with reasonable safety and that it gives an accurate assessment of the patient's ability to withstand exercise. It employs a metabolic approach: study of oxygen consumption (V'O2), carbon dioxide release (V'CO2), the respiratory quotient (RQ), the minute ventilation (V'E) and the respiratory equivalent for oxygen (REO2).

[Effects of physical training on the denervated human heart after orthotopic cardiac transplantation].

Three patients who had undergone an orthotopic cardiac transplantation followed a course of supervised intermittent physical training (60 to 80 per cent of the maximum load) involving three weekly sessions of thirty minutes, for a period of 150 +/- 80 days. During maximal effort, we observed increases of 50 per cent in the load in watts (0.05 less than p less than 0.

Metabolic implications during a 20-km run after heart transplantation.

The aim of the present study was to evaluate a heart transplanted patient who ran a 20-km race 9 months after surgery. Thirty-six healthy male subjects were studied during the same run and served as control group. Biochemical variables were determined in blood and urine samples collected before and after the race.

Study of the influence of nifedipine on the pharmacokinetics and pharmacodynamics of propranolol, metoprolol and atenolol.

The influence of chronic therapy with nifedipine on the pharmacokinetics of propranolol 80 mg twice daily, metoprolol 100 mg twice daily and atenolol 100 mg once daily was investigated in eight healthy volunteers. Nifedipine 10 mg three times daily did not affect the pharmacokinetics of metoprolol and atenolol whereas nifedipine shortened the time to peak plasma concentration for propranolol by about 1 h. Propranolol, metoprolol and atenolol provoked comparable decreases in heart rate measured at rest and during exercise.

Study of the coefficient of glucose assimilation during muscular exercise in diabetic adolescents deprived of insulin.

In six insulin deprived adolescent diabetics, the influence of muscular effort equal to 50% of the VO2 max on the coefficient of glucose assimilation was evaluated. During an IVTT the coefficient of glucose assimilation at rest was (0.59).