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Biomedical subjects

L Vanhees

Publications and source records attributed to L Vanhees.

At least 37 records · Page 2Linked to original sources
PubMed1991

Effect of antihypertensive medication on endurance exercise capacity in hypertensive sportsmen.

Beta-adrenoceptor blockade can influence exercise capacity negatively, but data on the effect of converting enzyme inhibition and of calcium entry blockade on exercise capacity in hypertensive sportsmen are scarce. This report deals with the effect of the various types of antihypertensive medication on endurance exercise capacity in 14 hypertensive sportsmen, aged 39 +/- 3 years and weighing 73 +/- 2 kg (mean +/- s.e.m.). The patients were treated for 3 weeks with either placebo, atenolol (50 mg/day) enalapril (10 mg/day) or verapamil (240 mg/day) following a double-blind randomized cross-over design. At the end of each treatment period, they performed an endurance exercise test on the bicycle until exhaustion at 70% of their previously determined exercise capacity. Venous blood was sampled before and after exercise. In comparison with placebo, total exercise duration was not affected by enalapril (-3 +/- 7%) or verapamil (-7 +/- 11%). During treatment with atenolol, two patients had to interrupt their intake of the beta-blocker because of side effects. In the 12 remaining subjects, exercise duration was significantly decreased by 38 +/- 12% (P less than 0.01). Atenolol also induced decreases in plasma-free fatty acid concentration before and after exercise and an increase in potassium concentration after exercise, whereas enalapril and verapamil did not induce metabolic changes. During exercise, systolic blood pressure was decreased by atenolol (P less than 0.001) and enalapril (P less than 0.01) and diastolic blood pressure by enalapril (P less than 0.001), verapamil (P less than 0.05) and atenolol(P = 0.06).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

Effect of verapamil on systemic and brachial artery hemodynamics in normal humans: comparison with effect of atenolol.

To clarify the hemodynamic effects of verapamil, we investigated in normal volunteers the effects of 4-day treatment with verapamil (240 mg/day) on left ventricular function and on systemic and brachial artery haemodynamics, in comparison with the effects of placebo and atenolol (100 mg/day). Left ventricular structure and function was evaluated by echocardiography, systemic hemodynamics were assessed by pulsed Doppler velocimetry of the ascending aorta, and brachial artery hemodynamics were assessed pulsed Doppler velocimetry of the brachial artery. Verapamil decreased systemic and brachial artery vascular resistance (p less than 0.05), increased cardiac output (CO, p less than 0.01) and brachial flow (p = 0.054), and did not affect blood pressure (BP) and heart rate (HR). In contrast, atenolol decreased BP, HR, and CO (p less than 0.001) but did not significantly affect brachial flow and systemic and brachial artery vascular resistance. We conclude that short-term administration of verapamil in normal humans produces systemic and brachial artery vasodilatation, with a reflex increase of stroke volume but not of HR.

Adult↗
PubMed1989

Converting enzyme inhibitors in the treatment of elderly hypertensives.

Angiotensin-converting enzyme inhibitors are gaining acceptance as safe and effective agents for treatment of hypertension. Addressed in this review of the available literature are the questions whether they are effective in lowering blood pressure in the elderly, whether their effects are age-related, and what effects, if any, do they have on morbidity and mortality in geriatric hypertension.

Aged↗
PubMed1988

Effect of calcium channel blockade and beta-adrenoceptor blockade on short graded and single-level endurance exercises in normal men.

The effect of verapamil (240 mg) on exercise capacity was studied during a short graded and a single-level endurance exercise test in 12 normal volunteers; it was compared to the effects of atenolol (100 mg x day-1). Intake of verapamil, atenolol and placebo, administered according to a randomized, double-blind cross-over design, was started 3 days before the exercise tests. Compared to placebo, verapamil did not affect peak oxygen uptake in the graded test or exercise duration in the endurance test. Heart rate, systolic blood pressure, rating of perceived exertion and respiratory data at submaximal and peak exercise were unaffected in either test. On the other hand atenolol reduced maximal oxygen uptake by 5% (p less than 0.001) and endurance exercise duration by 17% (p less than 0.05). Besides marked decreases in heart rate and systolic blood pressure during the two types of exercise, atenolol also reduced oxygen uptake at submaximal exercise levels and it increased the rating of perceived exertion (p less than 0.05), the latter only during the endurance exercise test.

Adrenergic beta-Antagonists↗
PubMed1987

Assessment of stiffness of the hypertrophied left ventricle of bicyclists using left ventricular inflow Doppler velocimetry.

Sixteen male bicyclists and 16 control subjects were studied to assess whether the left ventricular hypertrophy of athletes is associated with changes in diastolic left ventricular function. The cyclists had a larger left ventricular internal diameter on echocardiography (55.2 versus 47.9 mm; p less than 0.001) and a disproportionate increase in wall thickness relative to the internal diameter (0.48 versus 0.41; p less than 0.01), indicating a mixed eccentric-concentric type of hypertrophy. Left ventricular inflow Doppler velocimetry showed similar results in athletes and control subjects for peak flow velocities in the atrial contraction phase (30 versus 32 cm/s; p = NS) and in the early diastolic rapid filling phase (71 versus 67 cm/s; p = NS). The similar ratio of both velocities, that is, 0.43 in the cyclists and 0.49 in the control subjects, suggests that left ventricular distensibility is unaltered in cyclists. It is concluded that the left ventricular hypertrophy observed in cyclists is not associated with changes in ventricular stiffness, as estimated from left ventricular inflow Doppler velocimetry.

Adolescent↗
PubMed1987

Noninvasive assessment of systolic and diastolic left ventricular function in female runners.

Nine female runners and 9 matched control subjects were investigated with echocardiography and Doppler velocimetry to assess cardiac structure and systolic and diastolic left ventricular (LV) function at rest. LV mass was considerably larger in the athletes (171 vs 123 g; P less than 0.01). Minute distance, the Doppler index of cardiac output, was similar in runners and controls; the lower heart rate (P less than 0.01) of the athletes was associated with a higher stroke distance (P less than 0.05). The latter could be attributed to a larger end-diastolic LV internal diameter (46 vs 43 mm; P less than 0.05); wall stress and the various indices of systolic LV function were not different between runners and controls. Early diastolic LV function, estimated from the velocity of LV relaxation and the LV inflow pattern, and late diastolic function, assessed by Doppler velocimetry, were similar in runners and controls. The unchanged ratio of the peak velocities of LV filling during atrial contraction and early filling (0.49 vs 0.44; NS) indicates that LV distensibility is unaltered in the athletes. In conclusion, the higher left ventricular mass of female runners is not associated with changes of systolic and diastolic LV function.

Cardiac Volume↗
PubMed1987

Mechanism of hypotensive action of ketanserin in men.

The mechanism of the hypotensive action produced by ketanserin during chronic treatment in humans remains unknown. In contrast to previous reports, recent data show that ex vivo inhibition of the serotonin-induced platelet aggregation can be demonstrated in men during chronic ketanserin administration, provided that the pH is controlled in the in vitro assay. This test could be used as a tool to measure the degree of serotonin inhibition, at least at the platelet level.

Antihypertensive Agents↗
PubMed1987

Plasma renin system during exercise in normal men.

The exercise-related increase in plasma renin activity (PRA) and in the plasma concentration of angiotensin II (ANG II) and aldosterone (Aldo) was studied in 43 healthy volunteers whose 24-h urinary sodium excretion (UVNa) ranged from 10 to 250 mmol. Arterial blood samples were obtained at rest and during bicycle ergometry. Compared with rest, PRA, ANG II, and Aldo rose to a similar extent during light and moderate exercise. However, at peak exercise ANG II increased significantly more (P less than 0.001) than PRA and Aldo. Thus, with increasing intensity of exercise, the slope of the linear regression of ANG II on PRA became significantly (P less than 0.001) steeper, whereas at maximal exercise the Aldo response did not follow the acute rise in ANG II. At rest as well as during exercise, Aldo rose with increasing ANG II, but the stimulatory effect of ANG II on Aldo was attenuated with higher sodium intake, as estimated from UVNa. Finally, independent of the level of physical activity, UVNa was negatively correlated with PRA, ANG II, and Aldo.

Adult↗
PubMed1986

Beta-adrenoceptors and the regulation of blood pressure and plasma renin during exercise.

The relative role of beta 1- and beta 2-adrenoceptors in the regulation of blood pressure and plasma renin at rest and during exercise was studied in 17 normal male volunteers. They performed, in a randomized order and according to a double-blind crossover study design, three graded and uninterrupted exercise tests until exhaustion after being pretreated during 3 consecutive days with a placebo, with a predominantly beta 1-blocker (atenolol, 50 mg once/day), or with a predominantly beta 2-blocker (ICI 118551, 20 mg 3 times/day). Both drugs caused a decrease of heart rate, but the reduction by ICI 118551 was less pronounced at rest and no additional decline occurred at exercise. ICI 118551 did not affect blood pressure at rest, but during exercise diastolic blood pressure was higher than after a placebo. Atenolol lowered systolic blood pressure at rest and suppressed the exercise-induced increase in systolic blood pressure. At rest and during exercise plasma renin activity was lowered by predominantly beta 1-blockade and unchanged during beta 2-antagonism. The exercise-induced increase in plasma renin was, however, not affected by the beta 1-blocker. After atenolol the urinary excretion of aldosterone was decreased but the plasma aldosterone concentration was not changed. ICI 118551 did not alter plasma or urinary aldosterone. Our results therefore provide further evidence that the adrenoceptors mediating the release of renin at rest and during exercise in humans are partially of the beta 1-subtype, whereas beta 2-adrenergic receptors probably play only a minor role in the control of renin secretion, especially at exercise.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1986

Differentiation of exercise-induced metabolic responses during selective beta 1- and beta 2-antagonism.

The effect of beta 1- or beta 2-antagonism on the plasma levels of glucose, lactate, triglycerides, and free fatty acids was studied in seventeen normal male volunteers. All subjects performed three graded and uninterrupted exercise tests until exhaustion. Prior to each exercise test they received in a randomized order during three consecutive days either placebo or a predominant beta 1-blocker (atenolol, 50 mg once per day) or a predominant beta 2-blocker (ICI 118,551, 20 mg t.i.d.), according to a double-blind cross-over study design. Atenolol increased the plasma level of glucose at rest but did not influence the rise in plasma glucose during exercise. ICI 118,551 did not change the resting plasma glucose level, but it prevented the exercise-induced rise in plasma glucose, observed during placebo. During beta 1-antagonism the plasma lactate concentration at rest and during or after exercise was not different from placebo. During beta 2-blockade the exercise-induced rise in plasma lactate tended to be suppressed, and during recovery the plasma lactate levels were significantly lower than during placebo. The serum triglycerides concentration at rest and exercise was not altered, either by beta 1- or by beta 2-antagonism. Atenolol and ICI 118,551 did not affect the serum level of free fatty acids at rest, but at moderate exercise the serum free fatty acids concentration was lower during beta 1-blockade than during placebo. Our results provide further evidence that beta 2-adrenergic receptors are involved in the regulation of the plasma levels of glucose and lactate during exercise.

Adult↗
PubMed1985

Carotid baroreflex sensitivity and physical fitness in cycling tourists.

Carotid baroreceptors were stimulated with neck suction in 47 healthy subjects. Pulse interval lengthening was measured and the time course of the response was evaluated. Eight intensities of neck chamber suction were applied to select a criterion for computing the "RR response" that gives a significant linear relationship with the magnitude of the stimuli in the highest number of individuals. The best criterion was the maximal RR prolongation within 5 seconds after the onset of the stimulus. The slope of this relationship was defined as baroreflex sensitivity. The effect of physical fitness on baroreceptor function was investigated in 24 cycling tourists with a wide range of peak oxygen uptake and training characteristics. Baroreflex sensitivity averaged 7.3 +/- 0.8 msec X mm Hg-1 and was not significantly related to age, weight, basal heart rate, peak oxygen uptake and ventilation and other training characteristics. The results suggest that in man the so defined sensitivity of the carotid baroreflex control of heart rate is not influenced by the level of physical fitness and therefore the measurement of these characteristics can be neglected in evaluating baroreflex sensitivity.

Adolescent↗
PubMed1985

Plasma levels of renin, angiotensin II, and 6-ketoprostaglandin F1 alpha in endurance athletes.

Twelve male runners and 12 matched nonathletes performed a prolonged uninterrupted graded exercise test on the bicycle ergometer up to exhaustion to study blood pressure and plasma levels of renin (PRA), vasoconstrictor angiotensin II (ANG II), and 6-ketoprostaglandin F1 alpha (6-keto-PGF1 alpha), a metabolite of the vasodilator prostacyclin. In the athletes work load was increased by 30 W/4 min, and in the control subjects the increments of work load were adjusted to their lower exercise capacity to equalize total exercise duration. Blood was drawn, and blood pressure and O2 uptake (VO2) were measured at rest and at the fourth, eighth, and last steps of exercise. Peak VO2 averaged 60 +/- 1.6 ml . min-1 . kg-1 in the runners and 46.8 +/- 1.5 in the nonathletes. To evaluate differences between athletes and controls, PRA, ANG II, and 6-keto-PGF1 alpha were first adjusted for significant confounding factors, such as age, weight, hematocrit, 24-h urinary sodium excretion, and O2 uptake. PRA was significantly lower in the athletes (F = 11.2; P less than 0.01); ANG II was not different at rest, but its rise with exercise was less steep in the runners (F = 8.2; P less than 0.01), whereas 6-keto-PGF1 alpha was not different between the groups (F = 1.3; NS). Despite the differences in PRA and ANG II, however, blood pressure was similar in athletes and nonathletes (F = 0.0; NS).

6-Ketoprostaglandin F1 alpha↗
PubMed1985

Ketanserin: a new hypotensive drug?

The possible use of ketanserin for the chronic treatment of patients with essential hypertension was discussed based on the data exposed at this symposium. Its hypotensive effect is established during placebo controlled trials, but more data are needed to determine its relative potency compared to standard hypotensive drugs. The drug seems to act by reducing systemic vascular resistance, but the relative role of the serotonin and alpha inhibition in the chronic hypotensive effect in man is not yet known. Subjective side effects occur after the first dose, but seem to be less frequent during chronic treatment; organ toxicity has not been reported in the therapeutic doses. The drug could be particularly indicated in elderly hypertensive patients, especially in those with peripheral vascular disease. The influence on morbidity and mortality is not yet known.

Animals↗
PubMed1985

Relationship between carotid baroreflex sensitivity, physical fitness and activity in cyclists.

Carotid baroreceptors were stimulated with neck suction in 24 cycling tourists and pulse interval lengthening was measured. Eight intensities of neck chamber suction were applied to select a criterion for computing the RR response that gives a significant linear relationship with the magnitude of the stimuli in the highest number of individuals. The best criterion was the maximal RR prolongation within 5 s after the onset of the stimulus. The slope of this relationship was defined as baroreflex sensitivity. Baroreflex sensitivity averaged 7.3 +/- 0.8 ms/mmHg. The cycling tourists underwent an exercise test on a bicycle ergometer until exhaustion, and oxygen uptake, pulmonary ventilation, peak heart rate and exercise duration were determined. In single and multiple regression analysis, baroreflex sensitivity was not significantly related to basal heart rate, peak oxygen uptake and ventilation, duration of exercise or other training characteristics. The results suggest that in man the so-called sensitivity of the carotid baroreflex control of heart rate is not influenced by the level of physical fitness and therefore the measurement of these characteristics can be neglected in evaluating baroreflex sensitivity.

Adolescent↗
PubMed1984

Systolic time intervals in coronary heart disease at rest and during exercise: effect of physical training with and without beta blockade.

Systolic time intervals (STIs) were measured in recumbency at rest and in the sitting position at rest and during exercise, before and after a physical training program, in 28 patients with coronary heart disease. Fifteen patients were treated with a beta-blocking drug and 13 were not. After training, oxygen uptake at peak exercise increased similarly in both groups, by 41% and 37%, respectively, whereas heart rate at rest and during submaximal exercise decreased in both groups. Left ventricular (LV) ejection time (ET) adjusted for heart rate was not significantly affected by training. The rate-corrected preejection period (PEP) and the PEP/LVET ratio decreased after training. The changes in the STI after training were not related to the level of physical activity during testing and were similar in the patients treated with beta-blocking drugs and in those not so treated. The changes after training in STI at rest and at exercise in both treatment groups suggest that LV function improves during the training period and that beta-blockade does not alter this outcome.

Adrenergic beta-Antagonists↗
PubMed1984

Influence of physical training on blood pressure, plasma renin, angiotensin and catecholamines in patients with ischaemic heart disease.

Eighteen patients with ischaemic heart disease were trained for 3 months, three times a week. The effectiveness of the training programme was demonstrated by increases of 27% in peak oxygen uptake and 29% in exercise duration, and by a decrease in resting and submaximal heart rates. Blood pressure, however, was not significantly affected during the training period. At rest and at submaximal exercise plasma renin activity (PRA) was lower after training. Plasma angiotensin I concentration (PA I) and angiotensin II concentration (PA II) were not significantly affected. Plasma aldosterone concentration (PAC), only measured at rest, was not significantly changed after the training period, while plasma norepinephrine (PNE) and epinephrine (PE) concentrations were significantly decreased, but only at high levels of exercise. A reduced sympathetic tone after training, suggested by the lower heart rates and the tendency to a decrease in PNE, is a likely explanation for the decrease in PRA. However, despite this decrease, PA I, PA II, and PAC were not significantly changed after training; the reason for this disrepancy is unknown.

Angiotensins↗