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Biomedical subjects

H Kesteloot

Publications and source records attributed to H Kesteloot.

At least 127 records · Page 7Linked to original sources
PubMed1987

Evaluation of the efficacy and tolerance of the antiarrhythmic agent transcainide (R 54718).

The antiarrhythmic efficacy of transcainide has been studied in 41 patients. It abolished ventricular arrhythmias in 10 out of 12 patients after i.v. administration and in 11 out of 14 after oral administration. It also reduced ventricular arrhythmias during recovery from exercise. The maximum intravenous dose prolonged the PR-interval by 43% and QRS-duration by 37%. Side-effects observed in 6 out of 41 patients included Mobitz Type I AV block, complete bundle branch block, hypotension and increased arrhythmia frequency. Transcainide is a promising new antiarrhythmic drug which should be used with caution in patients with conduction disorders and impaired cardiac function. Its value and safety in the chronic oral treatment of life-threatening arrhythmias remains to be established.

Administration, Oral↗
PubMed1987

Effects of intravenous sotalol, aprindine and the combination of sotalol and aprindine on chronic high frequency ventricular arrhythmias in man.

The comparative antiarrhythmic efficacy of three different intravenous drug regimens was evaluated in 12 symptomatic patients (mean age: 72 years) with chronic high frequency ventricular arrhythmias (mean: 834 PVCs h-1). In a cross-over study with latin square distribution the following drug regimens were administered intravenously to all patients aprindine 2 mg kg-1, sotalol 1.5 mg kg-1, aprindine 1 mg kg-1 & sotalol 0.75 mg kg-1. The mean percentage of PVC reduction was 41% (P less than 0.05) for aprindine 2 mg kg-1; 51% (P less than 0.05) for sotalol 1.5 mg kg-1 and 72% (P less than 0.01) for the combined drug therapy (aprindine 1 mg kg-1 and sotalol 0.75 mg kg-1). The mean plasma concentration was 1371 ng ml-1 after administration of aprindine 2 mg kg-1 and 1730 ng ml-1 after infusion of sotalol 1.5 mg kg-1. After combined drug therapy, mean plasma levels were 942 ng ml-1 for aprindine and 992 ng ml-1 for sotalol. The different drug regimens were well tolerated in all patients and no side-effects occurred. Combination therapy consisting of a drug that prolongs action potential duration with an antiarrhythmic agent that has a high affinity for the inactivated channels may thus achieve an antiarrhythmic efficacy comparable to single agent therapy, permitting the use of lower dosages.

Aged↗
PubMed1987

On the within-population relationship between dietary habits and serum lipid levels in Belgium.

In a Belgian population group of 15,954 male and 2116 female subjects, an epidemiological survey has been conducted to investigate the relationship between dietary fat intake and serum total and HDL-cholesterol. The study has established, both in men and in women, a significant positive relationship between serum total cholesterol and the dietary intake of saturated fat and a significant negative one between serum total cholesterol and the intake of polyunsaturated fat and the P/S-ratio of the diet. At equal levels of consumption, polyunsaturated fat has a decreasing effect on serum total cholesterol which is about half the increasing effect due to saturated fat. Polyunsaturated fat and the P/S-ratio decrease the HDL-cholesterol value but only with borderline significance. The present study demonstrates the importance of dietary fat as a determinant of the serum lipid level within a population.

Adult↗
PubMed1987

Sodium channel block by a potent, new antiarrhythmic agent, transcainide, in guinea pig ventricular myocytes.

Transcainide is a new lidocaine analog that has been shown to suppress a range of cardiac arrhythmias in an initial clinical trial. We have evaluated the effects of transcainide on sodium channel current in guinea pig ventricular myocytes using the whole-cell patch-clamp technique. Reduction of sodium current by transcainide was concentration dependent, with an ED50 of approximately 0.5 microM (n = 9). This reduction of the sodium current exhibited little use dependence, and block did not accumulate even after 10-Hz pulse trains. Moreover, little or no recovery from block was observed even when cells were hyperpolarized to -160 mV for 1 min. We observed no reversal of sodium channel block after superfusing cells up to 1 h in drug-free solution. Thus, transcainide, unlike many other clinically useful antiarrhythmic agents, blocked sodium channels with very little time dependence or voltage dependence. These novel electrophysiological properties of transcainide may endow the agent with a unique spectrum of efficacy against certain arrhythmias. At the same time, the great potency of transcainide and its lack of reversibility, at least within an hour, mandate that the drug should be used with great caution.

Animals↗
PubMed1987

The relationship between cations and blood pressure in the People's Republic of China.

Blood pressure was measured in the north and in the south of the People's Republic of China in 1002 men and 1006 women. The 24-hour urinary excretion of sodium, potassium, calcium, magnesium, and creatinine was measured, and the relationship between urinary cations and blood pressure was studied. Blood pressure and 24-hour sodium excretion were higher in northern China than in southern China. With some exceptions, a positive correlation was found between urinary sodium and blood pressure and a negative one between 24-hour urinary potassium excretion and blood pressure. Urinary calcium correlated negatively and urinary magnesium did not correlate significantly with blood pressure. The sodium/potassium ratio correlated positively with blood pressure, and the calcium/magnesium ratio, negatively. This study confirms the positive within-population relationship between sodium intake and blood pressure in Oriental populations.

Anthropometry↗
PubMed1987

Effects of betaxolol on heart rate in patients with a recent transmural myocardial infarction.

A randomized double-blind trial was performed with betaxolol, a beta 1-selective and long-acting beta-blocker, in patients with a recent first uncomplicated acute myocardial infarction (AMI). Patients were treated between the 3rd and 14th day after the onset of AMI with either a single oral dosage of 20 mg betaxolol or placebo. The effects on heart rate, ventricular and supraventricular arrhythmias were studied by continuous 24 hours ECG recordings on the 7th and between the 9th to 12th after the onset of AMI and by a submaximal exercise test on the 12th day. Hourly mean, peak and minimal heart rate were during the whole day significantly lower in the active treatment group. In betaxolol treated patients diurnal variations in heart rate were definitely changed. No differences in the occurrence of ventricular arrhythmias were found between both groups; auricular fibrillation was more common in placebo treated patients. Heart rate and pressure rate product were significantly higher during exercise in the placebo group. During exercise ventricular arrhythmias were infrequent in both groups. The clinical tolerance of betaxolol was excellent.

Adrenergic beta-Antagonists↗
PubMed1987

Cardiovascular risk factors and mortality in women.

Men and women are subject to similar environmental influences but women have a markedly longer life expectancy, the difference in which is still increasing. In general, the level of saturated fat intake appears the most important determinant of life expectancy and it seems likely that this factor is even responsible for regional differences within a given country. In both men and women in Western populations, serum cholesterol levels are much higher than in Oriental populations. Women have higher total serum cholesterol than men in the age groups below 20 and over 50 years and this discrepancy may play a crucial role in the development of arteriosclerosis. Women also have markedly higher HDL-cholesterol levels than men in Western countries. Other important factors possibly accounting for the difference in life expectancy are the facts that in women less than 50 years of age, blood pressure is lower than in men and in women, smoking is much less prevalent. Overall, however, serum lipid levels and intake of saturated fat have a lesser influence on mortality in women than in men and, accordingly, they are lower predictors of mortality.

Adult↗
PubMed1986

Effect of sotalol, aprindine and their combination on maximum upstroke velocity of action potential in guinea-pig papillary muscle.

Microelectrode experiments were performed on papillary muscle of 11 guinea-pigs at driven heart rates of 60 and 120 b.p.m. to study the effect of sotalol 10(-4) M, aprindine 10(-6) M and the combination of both on Vmax, action potential duration and effective refractory period. Only sotalol exerted tonic Vmax block. Aprindine, sotalol and their combination produced an increase in phasic, combined tonic and phasic, and in steady state Vmax block: the effect of the combination on these parameters being larger than the effect of the single agents alone. Action potential duration was lengthened by both drugs and their combination. A statistically significant increase in effective refractory period was observed for sotalol and the combination sotalol-aprindine but not for aprindine. It can be concluded that simultaneous application of sotalol and aprindine enhances phasic, combined tonic and phasic, and steady state Vmax block with an unchanged effect of sotalol on repolarization. The effect of combinations can be explained on the basis of competition for the same receptor in the Na+ channel.

Action Potentials↗
PubMed1986

Effect of sotalol, aprindine and the combination aprindine-sotalol on monophasic action potential duration.

The effects of sotalol, aprindine and the combination aprindine-sotalol in the intact dog heart were evaluated during constant atrial pacing with the use of monophasic action potential (MAP) recording. A first group of five dogs was given 1.5 mg kg-1 body weight of sotalol, followed by a second infusion of 1.5 mg kg-1 30 min later. Both doses of sotalol produced a statistically significant increase in right atrial MAP duration at 50% of repolarization (RAMAP50) and right ventricular MAP duration at 90% of repolarization (RVMAP90). To a second group of six dogs aprindine 1 mg kg-1 and aprindine 2 mg kg-1 were administered intravenously. The infusion of aprindine did not alter right atrial and right ventricular MAP duration. The addition of 1.5 mg kg-1 of sotalol to the dogs pretreated with aprindine 2 mg kg-1 resulted in a 25% increase in RAMAP50 and a 21% prolongation of RVMAP90. In summary, sotalol lengthens atrial and ventricular monophasic action potential duration and still prolongs repolarization of monophasic action potentials after previous administration of aprindine. A combination of sotalol, a beta-adrenergic blocker possessing class III efficacy, with a class I antiarrhythmic agent may be useful with respect to their electro-physiological action.

Animals↗
PubMed1986

Relationship between left ventricular pressure and the calibrated apexcardiogram during abrupt outflow obstruction.

In order to study the influence of sudden left ventricular pressure rise on the calibrated apexcardiogram, 181 acute aortic occlusions were performed during systole in 7 dog experiments. For each beat preceding (CO) an occlusion and each occlusion (OC), peak systolic amplitude of left ventricular pressure (CO: 118.5 +/- 17.8 mm Hg; OC: 205.8 +/- 38.7 mm Hg) and apexcardiogram (CO: 48.8 +/- 16.7 mm Hg; OC: 63.0 +/- 25.8 mm Hg) were measured. Pressure gradients, ratios and surface areas of all tracings were digitally calculated. The cross-correlation function between pressure and apexcardiogram was also calculated in order to determine time lags. Significant correlations were found: between surface ratios and pressure gradient of pressure (r = 0.80, p less than 0.001) and of apexcardiogram (r = 0.79, p less than 0.001); between surface ratios of pressure and surface of apexcardiogram (r = 0.52, p less than 0.001). The data suggest that during isovolumic systole, the time integral of the left ventricular pressure and its change during the ejection phase define to a large extent the general shape and size of the apexcardiogram.

Animals↗
PubMed1986

The mechanism of disappearance of the physiologic third heart sound with age.

To study the mechanism of disappearance of the physiologic third heart sound (S3) with advancing age, combined phonoechocardiographic and phonomechanocardiographic recordings from 165 normal subjects between 6 and 62 years old were quantitatively analyzed. Nearly all individuals under 40 years old had a recordable S3. Although recordable in 38.6% of the 44 subjects over 40 years old, the physiologic S3 found in adults was less intense and occurred later in diastole when compared with that in children and adolescents. Marked changes in left ventricular filling hemodynamics were observed with aging, including an increase in left ventricular wall thickness and mass, a prolongation of the left ventricular isovolumetric relaxation period, a decrease in left ventricular early diastolic filling and wall thinning rates, and a reduction in the height and steepness of the rapid filling wave measured on the calibrated left apexcardiogram (linear correlation with age significant at p less than .001 for all parameters). Although less pronounced, these changes were very similar to the diastolic abnormalities found in patients with pressure overload left ventricular hypertrophy. Therefore, the higher pressure load imposed on the left ventricular wall due to the well-known gradual increase in blood pressure that occurs during normal growth and adulthood appears to be the most likely explanation for the observed changes in diastolic filling. It is concluded that the later occurrence, the diminishing amplitude, and the eventual complete disappearance of the physiologic S3 with age results from a decrease in early diastolic left ventricular filling and subsequent deceleration of inflow caused by the development of relative left ventricular hypertrophy in adulthood as compared with childhood.

Adolescent↗
PubMed1986

New techniques in mechanocardiography.

Many new approaches towards noninvasive cardiology have been introduced into clinical practice recently and "old" methods such as apexcardiography reevaluated. Problems concerning calibration of some of these systems will be discussed briefly. Advances have been made recently in the field of optical methods: chest wall displacement can be obtained using light sources (Moiré interferograms and laser displacement). Combination of different methods: echo-, phono- and mechanocardiography, have led to completely new insights in the genesis of low frequency and high frequency vibrations of the heart. Digital signal processing methods have been developed for the analysis of combined echo-phono-mechanocardiograms. In this way left ventricular function can be determined in a very effective way.

Computers↗