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Biomedical subjects

H Kesteloot

Publications and source records attributed to H Kesteloot.

At least 145 records · Page 8Linked to original sources
PubMed1985

Efficacy and tolerance of intravenous lorcainide in patients with normal and impaired intraventricular conduction.

The effectiveness and safety of intravenous lorcainide was evaluated in 14 patients with normal (QRS less than 110 ms) and in 9 patients with prolonged QRS duration (QRS greater than or equal to 110 ms) showing chronic high frequency premature ventricular complexes (mean value of PVCs 17 min-1). Lorcainide was infused intravenously by intermittent bolus at 10 mg every minute to a total dose of 160 mg with exception of 5 patients with a prolonged QRS duration who only received 100 mg. The overall reduction of PVCs 1 hour after administration of the drug was 86% (p less than 0.05) in the patients with normal QRS duration and 98.5% (p less than 0.05) in the patients with a prolonged QRS duration. The mean plasma drug level achieved 1 h after treatment was 280 +/- 60 ng/ml in the patients with QRS less than 110 ms and 170 +/- 40 ng/ml in the patients with a QRS greater than or equal to 110 ms. Heart rate and blood pressure did not change but a significant increase (p less than 0.05) in QRS duration (+37%) was observed 30 min after the infusion of 160 mg lorcainide in the patient group with normal QRS duration. Lorcainide was well tolerated. Mild adverse effects were observed in five patients including: warmth sensation, vomiting, paresthesias, transient hypotension and the development of a junctional escape rhythm. Therefore lorcainide appears to be a safe and effective drug, that can even be administered to patients with a prolonged QRS duration.

Adult↗
PubMed1985

Intramyocardial pressure in the canine heart. An experimental study.

During 11 acute open-chest experiments with dogs, intramyocardial pressure was measured in the anterior wall of the left ventricle with a miniature pressure transducer mounted on a 1.6 mm diameter needle. Pressures were measured at the subendocardium (+/- 10 mm), midwall (+/- 7.5 mm), and subepicardium (+/- 5 mm). Simultaneous recordings of left ventricular pressure and two measures of intramyocardial pressure were made during control, acute volume overload, and after administration of verapamil. Maximal amplitude of the subendocardial pressure was higher and the maximal amplitude of the subepicardial pressure was lower than maximal left ventricular pressure for all interventions (p less than 0.001 and p less than 0.01). During volume overload left ventricular pressure increased more than intramyocardial pressure (left ventricular pressure 34%, subendocardial pressure 6%, midwall pressure 14%, and subepicardial pressure 14%). After the administration of verapamil intramyocardial pressure decreased more than left ventricular pressure (left ventricular pressure 16%, subendocardial pressure 26%, midwall pressure 13%, subepicardial pressure 32%). Positive and negative first derivatives of subendocardial pressure were higher than those of left ventricular pressure during control and after verapamil (between p less than 0.01 and p less than 0.001). Positive and negative first derivatives of subepicardial pressure were lower than those of left ventricular pressure during all interventions (p less than 0.001). The timing of the C-point (onset of mechanical contraction) and the positive first derivative of all tracings was synchronous within 8 msec in all interventions. The 0-point (crosspoint of the tangent to the diastolic plateau and the tangent to the relaxation slope; early diastole) of intramyocardial pressure came later than the 0-point of left ventricular pressure, indicating longer relaxation times in the myocardium (subendocardial pressure: control, p less than 0.001, volume, p less than 0.05, verapamil, no significance; midwall pressure: between p less than 0.05 and p less than 0.001; subepicardial pressure: between p less than 0.01 and p less than 0.001).

Animals↗
PubMed1984

Laser method for recording displacement of the heart and chest wall.

Several non-invasive methods are in use for recording mechanocardiograms. In this paper a new laser technique will be presented to measure heart motion, chest wall displacement and other displacement curves of cardiovascular structures. Principles of the laser displacement technique are described. The measurement range within which displacement is sensed, is 32 mm with a detector to object distance of 25 cm and a resolution of 8 micron (digital output) or 16 micron (analogue output). The specific surface of which motion is sensed is 1 mm2. The sensitivity of the system is 156 mV/mm at a frequency bandwidth of 0-2 kHz. Assessment of the laser displacement technique was carried out during 6 dog experiments on the closed chest, on the exposed heart, on blood vessels and also on the chest wall of 5 normal subjects. Displacement of the chest wall at the apical site ranges between 0.3-0.8 mm and of the exposed heart between 3-10 mm.

Animals↗
PubMed1984

Serum lipid distribution and mortality in Belgium.

During the year 1982 serum cholesterol and apolipoprotein A1 and B levels were measured in 1319 male subjects (mean age 20 years) from different provinces of Belgium. The serum cholesterol level and the apolipoprotein B level were distinctly lower in Dutch-speaking than in French-speaking subjects. An increase of 1.1 mg% of total cholesterol was found per kg per consumer unit per year of butter consumed and a decrease of 1.1 mg% per kg per consumer unit per year of margarine consumed. The higher cholesterol value in French-speaking subjects correlated significantly with a high regional mortality from all causes and from ischaemic heart disease in male subjects of the 45-64-year age group. A 10 mg% difference in serum cholesterol at the age of 20 years corresponds with an increase in mortality from all causes of 20% and from ischaemic heart disease of 21%. A significant difference in log GGT (gamma glutamyl-transpeptidase)--possibly due to differences in alcohol consumption--was observed between the provinces of Belgium. The difference in cholesterol and apolipoprotein B level remained significant after adjustment for log GGT.

Adult↗
PubMed1984

Efficacy and tolerance of intravenous flecainide in patients with chronic high frequency ventricular arrhythmias.

The effectiveness and safety of intravenous flecainide was evaluated in 33 patients with chronic high frequency premature ventricular complexes (mean value of PVCs 23.7 min-1). Flecainide was injected intravenously at a rate of 20 mg per 2 min until complete disappearance of ventricular arrhythmias or up to a total dose not exceeding 200 mg. Total suppression of PVCs occurred in 31 out of 33 patients at the end of the injection (mean dose 132 mg). The overall reduction of PVCs was 94 per cent (P less than 0.001) at the end of infusion and 74 per cent (P less than 0.001) 1 h later. The mean plasma drug level attained 1 h after administration was 287 ng ml-1 (range 82-984). Heart rate and blood pressure did not change, but a significant increase (P less than 0.001) in PR (+12%), QRS (+13%) and QTc (+4%) duration occurred after drug administration. Flecainide was well tolerated. An idioventricular tachycardia was induced in one patient and two patients experienced side effects of the central nervous type: dizziness, blurring of vision and a sensation of warmth. In view of its activity flecainide appears to be a valuable addition to the antiarrhythmic armamentarium.

Adult↗
PubMed1984

Epidemiological studies on the relationship between sodium, potassium, calcium, and magnesium and arterial blood pressure.

Populations with a high sodium intake have a high prevalence of hypertension and a high mortality and morbidity due to cerebrovascular disease. Within populations, however, it is very difficult to demonstrate a significant correlation between sodium intake and blood pressure. Experimental evidence exists demonstrating a blood pressure-lowering effect of potassium. In Korea, where sodium consumption is very high, we were able to demonstrate a positive relationship between sodium intake and a negative relationship between potassium intake and blood pressure. We were unable, however, to demonstrate such an effect in Belgium. Total serum calcium positively correlates with blood pressure in Belgium in male subjects, while 24-h urinary excreted calcium positively correlates with blood pressure both in Korea and in Belgium. Significant interactions exist between the amount of sodium and potassium in the 24-h urine and the total serum calcium level. In a subgroup of 297 male subjects no correlation was found between the serum ionized calcium level and blood pressure. Magnesium, a calcium antagonist, could be the factor responsible for the relationship between water hardness and cardiovascular morbidity. In Korea, however, we were unable to find a significant relationship between 24-h urinary magnesium and both systolic and diastolic blood pressure.

Adult↗
PubMed1984

Mechanism of aprindine induced agranulocytosis: direct toxicity on CFU-C and CFU-GEMM.

The in vitro bone marrow growth of 2 patients with aprindine-induced agranulocytosis was studied. Granulocyte-macrophage committed stem cell (CFU-C) growth is inhibited by aprindine in a dose dependent manner. 50% inhibition of CFU-colony growth (TD50) was seen at 5.1 and 3.4 micrograms aprindine/ml medium respectively. The TD50 of control marrow CFU-C was 3.2 micrograms/ml. 100% inhibition was seen at 16 micrograms aprindine/ml, both in patients and controls. Pluripotential stem cell growth (CFU-GEMM) in control marrow was equally inhibited in a dose dependent manner by aprindine, though to a lesser extent (TD50: 9.1 micrograms/ml) and with relative sparing of pure megakaryocyte and erythroid colonies. Co-culturing of patients marrows with their respective acute phase serum did not inhibit CFU-C growth.

Aged↗
PubMed1984

Diastolic properties of the left ventricle in normal adults and in patients with third heart sounds.

To explore the pathogenesis of the third heart sound (S3), left ventricular hemodynamics in early diastole were studied during catheterization in normal adults without S3S (group I, n = 12) and in cardiac patients with S3S as the result of severe mitral regurgitation (group II, n = 11), dilated cardiomyopathy (group III, n = 24) or restricted left ventricular filling (group IV, n = 4). The height and steepness of the rise in left ventricular pressure after minimum diastolic pressure (the so-called rapid filling wave), maximum dV/dt, and the time constant of fall in isovolumetric pressure were measured. The completeness of relaxation was evaluated from the number of time constants elapsed at the time of minimum diastolic pressure. Pressure-volume data were fitted to simple elastic and viscoelastic models incorporating inflow rate into the equation. In all patients with S3S a significantly higher and steeper rapid filling wave was found than in normal adults. Maximum dV/dt was significantly greater in group II (1084.9 +/- 416 ml/sec; mean +/- SD) than in the other groups (463.9 +/- 177.1 ml/sec in group I, 448.8 +/- 134.0 ml/sec in group III, and 709.9 +/- 226.8 ml/sec in group IV). No significant differences in left ventricular chamber elastic properties in the different groups were found. However, intrapatient comparisons of the results of the use of elastic and viscoelastic equations revealed a significantly better curve fit (r = .930 vs .968, p less than .005) and a much higher viscous constant for group III. Similar results were found in group IV.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1984

The genesis of the third and fourth heart sounds. A pressure-flow study in dogs.

To examine the mechanism of mitral flow deceleration in diastole and its potential influence on the genesis of third (S3) and fourth (S4) heart sounds, we simultaneously recorded left atrial and left ventricular pressures (micromanometers), mitral flow velocity (electromagnetic catheter-tip flow velocity meter), and internal and external phonocardiograms in 25 open-chest dogs. Diastolic time intervals, transmitral pressure gradients (planimetry), maximum mitral flow velocity, and acceleration and deceleration of flow were measured under different loading conditions. It was found that deceleration of mitral flow in early and late diastole is always caused by a negative transmitral pressure gradient. After volume loading, diastolic pressures, positive (forward) and negative (backward) transmitral pressure gradients, and acceleration and deceleration of flow increased, and an S3 or S4 appeared (20:25 dogs). These sounds occurred during the phase of flow deceleration and could be recorded from the chest wall, inside the left ventricle, and directly from the epicardial surface of the freely exposed left ventricular wall. After balloon occlusion of the inferior vena cava (17:25 dogs), the opposite changes were observed and gallop sounds disappeared. The results indicate that the left ventricular pressure rise in response to filling reverses the transmitral pressure gradient and decelerates flow. Deceleration of inflow by the left ventricular wall in early and late diastole may represent a key mechanism in the genesis of S3 and S4.

Animals↗
PubMed1984

Influence of transmural pressure on retrograde pressure pulse transmission velocity in the canine superior vena cava.

The influence of intrathoracic and intraluminal pressure on venous pressure pulse propagation velocity in the superior vena cava was investigated in acute canine experiments. The propagation velocity of distinct points of the venous pressure curve was measured under different conditions of preload, during expiratory and inspiratory apnea and during positive-negative pressure respiration. Under control conditions transmission velocities varied from 1.07 m/s to 3.29 m/s. After volume expansion propagation velocities rose significantly and varied from 1.09 m/s to 6.48 m/s. During expiratory apnea and at peak negative expiratory pressure, the propagation speed of distinct pressure points was higher than during inspiratory apnea and at peak positive inspiratory pressure. Significant linear correlation coefficients were found between the transmission velocities of different distinct pressure points and the transmural pressure, but not between the propagation speed and the intraluminal pressure.

Animals↗
PubMed1984

Dose related efficacy of betaxolol in combination with nitroglycerin in patients with angina pectoris: a double blind cross-over study.

The effect of three different oral doses, 5 mg, 10 mg and 20 mg of betaxolol (BTX), a new long acting cardioselective beta-adrenergic blocking drug, on exercise tolerance was studied in a randomized double blind, cross-over study with latin square distribution in nine male patients with angina pectoris, under continuous therapy with oral nitroglycerin. BTX caused a significant reduction of heart rate (p less than 0.001) for all different dose levels during exercise. Systolic blood pressure was significantly decreased at peak exercise for BTX 10 (p less than 0.01) and BTX 20 (p less than 0.001). During the three treatment periods a significant drop of the rate pressure product (p less than 0.01) was observed and a statistically significant improvement of exercise tolerance, before the occurrence of anginal pain, could be demonstrated. No differences could be detected in oxygen uptake, carbon dioxide output and ventilation between placebo- and treatment periods. BTX was well tolerated in all patients and exerted its effect also in the presence of nitroglycerin. Its cardioselectivity, ease of dosing and complete absence of side effects makes BTX an attractive choice as antianginal agent for chronic use.

Adrenergic beta-Antagonists↗
PubMed1984

Urinary cations and blood pressure--population studies.

The relationship between urinary cations and blood pressure has been examined by means of multiple regression analysis with the inclusion of age, BMI, urinary 24-hour creatinine, heart rate and the 24-hour urinary excretion of Na, K and, in a subsample, of Ca and Mg. In Korea where the Na intake is high and the K intake is low a significant positive relationship was found between 24-hour urinary Na and blood pressure and a negative one between 24-hour urinary K and blood pressure. In Belgium, however, a negative relationship was found between 24-hour urinary Na and the Na/K ratio and blood pressure. In a subsample the 24-hour urinary Mg excretion significantly and negatively correlated with diastolic blood pressure both in men (slope -0.245 mm Hg/mmol Mg) and in women (slope -0.525 mm Hg/mmol Mg) while no significant relationship was found with 24-hour urinary Ca. Further study of the importance of Mg for blood pressure regulation is warranted.

Adult↗