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Biomedical subjects

J Claessens

Publications and source records attributed to J Claessens.

At least 19 recordsLinked to original sources
PubMed2000

Physiological or pseudophysiological ECG changes in endurance-trained athletes.

"Sudden cardiac death" in seemingly healthy, active, and asymptomatic people has always been a tragic fact and is now occurring more frequently. Thus, the preventive detection of "subjects at risk" becomes a priority. A traditional resting electrocardiogram can sometimes give useful indications. Fifty-two competitive triathletes were compared with 22 control persons with similar anthropometric parameters. All subjects underwent the same noninvasive cardiac exploration with electrocardiography, bidimensional echo-Doppler examination, and maximal spiroergometric exercise tests, on a stationary bicycle as well as on a treadmill. In the triathletes we noted manifest signs of eccentric as well as concentric left ventricular hypertrophy with arguments for a supernormal diastolic left ventricular function, with important hemodynamic adjustments and with consequences on the resting electrocardiogram. We described "ten commandments" in evaluating the resting electrocardiogram of healthy competitive athletes. We suspect that the occurrence of ventricular premature beats at peak load of a maximal exercise could be the first expression of a pathological cardiac adaptation to sports activities. The resting electrocardiogram can show interesting details in detecting the "subjects at risk" for problems such as possible lethal arrhythmias and "sudden cardiac death." The analysis of the four subgroups of triathletes compels us to feel dubious about the "athletic heart syndrome" as a physiological entity. In several cases the "athletic heart" is possibly a transitional situation to a pathological hypertrophic and dilated cardiomyopathy.

Adult↗
PubMed2000

Changes in mortality of acute myocardial infarction as a function of a changing treatment during the last two decades.

Forty years ago, after the establishment of coronary care units, a significant decrease in mortality of acute myocardial infarction was noted. Twenty years ago, the break-through of thrombolysis realized once again a significant decrease in mortality. In this study we compare, in a rather small community hospital, the mortality and safety of thrombolytic therapy in acute myocardial infarction with a more conventional, conservative medical therapy. We examined all cases of acute myocardial infarction between 1978 up to 1998 inclusive, concerning treatment and mortality rate after a six month period. To be included in the study, acute myocardial infarction had to fulfill particular inclusion criteria. A total of 1863 cases of acute myocardial infarction were included. The mortality rate of patients with acute myocardial infarction treated with thrombolytic agents was strikingly lower and statistically very significantly different (p < 0.001) in comparison with the mortality rate of patients treated with heparin or coumarine derivatives. The mortality rate dropped from 10.57% in the coumarine group and from 14.95% in the heparin group to 5.41% in the alteplase group, to 4.95% in the anistreplase group and 4.00% in the streptokinase subgroup. The complications directly connected to the treatment did not seem to be different between the five groups, and they were also not more frequent by using thrombolytic agents. In the last 20 years, better preventive measures (life habits, diet, medication) and trials to better control the risk factors have not influenced greatly the average amount of cholesterol in patients with an acute myocardial infarction. Also the percentage of patients with high blood pressure has hardly decreased over the last 20 years. The mortality associated with acute myocardial infarction has decreased significantly with the use of thrombolytics. In most cases, thrombolytics are administered routinely and safely. In this way, they are the first choice therapy for myocardial infarction in smaller hospitals. To obtain excellent coronary patency, thrombolytic agents with a long half-life and with PAI-1 resistance are required in the future. The current measures and medical therapies seem to be insufficient to control the risk factors for coronary atherosclerosis.

Cholesterol↗
PubMed2000

Echocardiographic and physiological performance characteristics of triathletes.

BACKGROUND: Endurance sports require a variety of physiological adaptations. OBJECTIVE: To examine the structural and functional heart adaptations and their hemodynamic implications in triathletes. PATIENTS AND METHODS: A group of 52 male triathletes was compared with a control group of 22 healthy male nonathletes. All of the subjects were given a bidimensional cardiac Doppler echocardiography examination and administered maximal exercise tests with lactic acid determinations, on a bicycle ergometer and a treadmill. RESULTS: The triathletes showed clear structural and functional heart adaptations with concentric and eccentric hypertrophy with evidence of a supernormal diastolic left ventricular function. The performance capacity of the triathlete differed significantly from that of the control subject. The maximal oxygen consumption and the maximal oxygen consumption per kilogram on the bicycle and on the treadmill were significantly higher in the triathletes. The same results and conclusions were obtained concerning aerobic capacities and power outputs on a bicycle ergometer at blood lactate concentrations of 2, 3 and 4 mmol/L. The heart rate 6 min after the start of exercise is a significant parameter for the evaluation of the physical condition of a subject. The lactic acid determinations during the recovery phase enabled important conclusions to be drawn about the physical condition of the subjects. CONCLUSIONS: The triathletes showed evidence of important structural and functional heart adaptations with hemodynamic implications. The maximal performing capacities, on the bicycle as well as on the treadmill, were distinctly higher in the triathlete group. Furthermore, the aerobic and anaerobic capacities were significantly different between the groups. In this context, the heart rate 6 min after the start of exercise and the blood lactate concentrations 20 min after the maximal exercise test were significant parameters. It was not always the best triathletes who had the most significant structural cardiac adaptations. Thus, the 'athletic heart' syndrome as a physiological entity is questioned.

Adaptation, Physiological↗
PubMed1999

Structural heart adaptations in triathletes.

OBJECTIVE: To perform a triathlon in aerobic conditions, a variety of cardiovascular, haemodynamic and metabolic adaptations are required. The heart is the central concern and also the most important limiting factor. In this study we investigate the structural and functional heart adaptations of a group of triathletes. METHODS AND RESULTS: A group of 52 male triathletes was divided into 4 subgroups in function of their athletic results and compared with a control group of 22 healthy, very active but no athletic men. The groups had comparable anthropometric and general physical characteristics. Very significant differences in cardiac structure and cardiac function were observed between the groups. In the triathletes, we registered distinct signs of significantly mixed eccentric and concentric hypertrophy. Unlike the findings in a pathological left ventricular hypertrophy, the diastolic left ventricular function in triathletes was completely normal and even better than in the control group. The late passive diastolic filling period of the triathlete, in particular, seemed to have specific characteristics. The comparison between the subgroups of triathletes shows us that genetic factors probably play an important role in the cardiac adaptations in triathletes. CONCLUSIONS: In our opinion the "athletic heart" in triathletes is not a specific "physiological entity" but is a transitional phase to a dilated hypertrophic cardiomyopathy. Our study yields some arguments for the following proposition: "People are born as elite athletes, with specific characteristics of the left ventricle and with a specifically supernormal diastolic left ventricular function."

Adaptation, Physiological↗
PubMed1992

Are the various thrombolytic agents equally effective in the treatment of acute transmural myocardial infarction?

While it is no longer possible to imagine the treatment of an acute transmural myocardial infarction without the use of thrombolytic agents, some discussion still exists as to the choice of the thrombolytic agent. Our study concerns a group of 160 patients with an acute transmural myocardial infarction, 60 of whom were treated with anistreplase, 52 with streptokinase and 48 with alteplase. Statistically, the administration of anistreplase was associated with a significantly higher frequency of ventricular arrhythmias in comparison to the other thrombolytic agents, whereas after subsequent coronary angiography, the anistreplase group revealed a significantly lower number of completely occluded coronary arteries. The data from this study demonstrate that anistreplase is a very valuable thrombolytic agent. It may even be more effective than streptokinase and alteplase in the treatment of acute myocardial infarction when the patency of the coronary arteries 1 month after the acute coronary event is considered the primary endpoint.

Anistreplase↗
PubMed1992

Interventional intra-arterial ultrasonography as an exclusive method of exploration to determine atherosclerotic lesions of the arterial wall at a preclinical stage.

Intravascular ultrasonography of the peripheral arterial system was applied following coronarography in 56 patients with one or several critical stenoses of the coronary arteries. Even though the clinical vascular examination and the subsequent noninvasive examination of the peripheral arterial system of all these patients turned out to be completely normal, intra-arterial ultrasonography was able to reveal important atherosclerotic alterations in the wall of the abdominal aorta and of the iliac-femoral arterial system in 51 of these patients. Intra-arterial ultrasonography appears to be a very sensitive method of exploration, permitting atherosclerotic changes of the arterial wall to be detected at a very early preclinical stage, long before these deviations could have caused symptoms.

Aorta, Abdominal↗
PubMed1992

Detection of silent arteriosclerotic lesions by intra-arterial ultrasonography.

OBJECTIVES: The aim of this study was to detect arteriosclerotic changes in the arterial wall at a preclinical stage. That is at a moment when these arteriosclerotic lesions are still fully asymptomatic and when the usual non-invasive vascular investigation techniques do not show any abnormalities. METHODS: Fifty-six patients with one or more critical stenoses of the coronary arteries, but with a completely normal peripheral vascular examination, were submitted to intravascular ultrasonography of the peripheral arterial system following coronary arteriography. Sonicath Ultrasound catheters were used and images were created with a Diasonics Imaging System. RESULTS: Although these 56 patients, after a profound noninvasive investigation, were classified as having perfectly normal peripheral arteries, we found severe arteriosclerotic wall abnormalities of the abdominal aorta and/or the iliac arterial system in 5% of the subjects. In addition, this exploration technique was used to evaluate the nature and the structure of the registered degenerative arteriosclerotic lesions. CONCLUSIONS: Intra-arterial ultrasonography obviously is a very sensitive investigation method which allows tracing arteriosclerotic changes of the arterial wall in a very early preclinical stage. The external ultrasound exploration techniques still have several important limitations, which, of course, do not hinder the intravascular application. The remaining disadvantage of the intra-arterial ultrasonography is however its invasive character.

Aorta, Abdominal↗
PubMed1991

The intra-arterial ultrasonography as an exclusive exploration method to determine atherosclerotic lesions of the arterial wall in a preclinical stage.

An intravascular ultrasonography of the peripheral arterial system was applied following on the coronarography to 56 patients suffering from one or several critical stenoses on the coronary arteries. Though the clinical vascular examination and the subsequent noninvasive examination of the peripheral arterial system of all these patients turned out to be completely normal, the intra-arterial ultrasonography was able to reveal important atherosclerotic alterations in the wall of the abdominal aorta and of the iliac arteries in the case of 51 of these patients. The intra-arterial ultrasonography appears to be a very sensitive method of exploration, permitting atherosclerotic changes of the arterial wall to be detected at a very early pre-clinical stage, even long before these anomalies could have caused a specific pattern of complaints.

Aortic Diseases↗
PubMed1987

Comparative effects of doxazosin and hydrochlorothiazide on serum lipids and blood pressure in essential hypertension.

The efficacy and safety of doxazosin (mean dosage 6.9 mg, range 1 to 16) in the treatment of essential hypertension were compared in a double-blind study with those of hydrochlorothiazide (HCTZ) (mean dosage, 84.6 mg, range 25 to 100) in 104 hypertensive patients treated once daily for 6 months. Thirty-five patients were also assessed for comparative effects of the 2 agents on serum lipid parameters. Doxazosin produced potentially favorable changes from baseline in the concentrations of serum lipid fractions (total triglycerides, total cholesterol, high density lipoprotein [HDL] cholesterol and the derived HDL/total cholesterol ratio) compared with HCTZ. The decreases in total triglyceride and total cholesterol concentrations and an increase in the HDL/total cholesterol ratio were significantly different (p less than 0.006) from the opposite changes observed with HCTZ. Clinically relevant decreases from baseline in supine and standing blood pressures at 24 hours after administration did not significantly differ between the 2 agents. The incidence and severity of side effects were similar for both drugs. Three patients receiving doxazosin and 6 receiving HCTZ were withdrawn due to drug-related clinical side effects including 2 patients receiving HCTZ who were withdrawn because of laboratory test abnormalities. Eight HCTZ- and 1 doxazosin-treated patients developed hypokalemia and 6 HCTZ-treated patients developed hyperuricemia. These findings indicate that doxazosin and HCTZ provide comparable antihypertensive efficacy after 6 months of treatment using a once-daily regimen, but doxazosin produces a beneficial effect on the serum lipid profile as well as fewer biochemical aberrations.

Adrenergic alpha-Antagonists↗
PubMed1980

A comparative study of blood pressure and sodium intake in Belgium and in Korea.

A comparative blood pressure and sodium excretion were higher in Korea than in Belgium. By multiple regression and covariance analysis an independent positive association between sodium and blood pressure and a negative correlation between potassium and blood pressure were found in some population subgroups and in the total population studied in Korea. In Belgium a positive association between sodium and blood pressure was found when higher powers of age, height, weight and sodium were included in the analysis. The independent influence of sodium on blood pressure was relatively small, amounting to about 2 mm Hg of pressure rise for an increase in 24-h excretion of 100 mmol of sodium.

Analysis of Variance↗