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Biomedical subjects

G de Backer

Publications and source records attributed to G de Backer.

10 recordsLinked to original sources
PubMed1992

Decreased exercise capacity in mild essential hypertension: non-invasive indicators of limiting factors.

Available data suggest that exercise capacity is limited in hypertension. The mechanism of this reduced maximal exercise capacity has not been fully elucidated. In this study 22 patients with mild essential hypertension (162 +/- 22 mmHg systolic and 95 +/- 8 mmHg diastolic) and 36 normotensive control subjects (128 +/- 13 mmHg systolic and 80 +/- 7 mmHg diastolic) (P less than 0.01) performed an ergometer test till exhaustion. Body mass index in the two groups did not differ. The maximal oxygen consumption VO2 was lower in the hypertensive group (18 +/- 7 versus 23 +/- 8 ml/kg/min; P less than 0.02) as was the maximal workload (141 +/- 52 vs. 185 +/- 70 Watt; P less than 0.01). Rate pressure product rose only 2.7 fold in hypertensive patients versus 3.5 fold in the control group (P less than 0.001). In hypertensive patients maximal workload decreased with increasing resting systolic blood pressure (P less than 0.05) while in the normotensive subjects maximal workload rose with increasing resting systolic blood pressure (P less than 0.05). In conclusion both high and low blood pressure was associated with a decreased maximal voluntary exercise capacity. Even mild hypertension was accompanied by lower maximal exercise capacity. Hypertensive patients also had a lower maximal VO2 and lower maximal rate pressure product than did normotensive subjects.

Blood Pressure↗
PubMed1991

Methodological considerations on intra- versus interpopulation correlation studies.

Epidemiological studies on the diet-health relationship have frequently resulted in confusing controversies rather than in clear and consistent findings. As an illustration of this phenomenon the relationship between dietary cholesterol and coronary heart disease (CHD) is used in this presentation. The epidemiological evidence favoring a strong and causal relationship between dietary cholesterol, serum lipids and CHD relied until some years ago largely on studies between populations. However these studies are more susceptible to confounding error. Therefore epidemiological studies have been conducted within populations looking into the relationship between dietary cholesterol, CHD risk and CHD frequency on the individual level. Until recently no consistent association had been observed between dietary cholesterol and serum total cholesterol levels or between dietary cholesterol and CHD mortality in homogeneous groups of individuals; this relates probably to methodological problems in measuring the dietary variable with sufficient precision. More recent studies using a more precise dietary methodology and a prospective study design over longer time periods result in observations that are more in line with the interpopulation study observations. Besides epidemiological evidence it is necessary to compare these findings with those from experimental work and from clinical studies. This approach has the best chance to separate ecological fallacy from real existing associations between diet and health.

Animals↗
PubMed1988

Physiologic pacing in the elderly. Effects on exercise capacity and exercise-induced arrhythmias.

It is not clear whether hemodynamic and other benefits from dual-chamber pacing also exist in elderly patients. We studied a group of 18 elderly patients (mean age 74 +/- 4 yrs) with exercise testing in DDD and VVI modes in a randomized way to compare the effects of these pacing modes on exercise capacity, atrial rate and exercise-induced arrhythmias. Patients were selected when complete heart block was present without clinical evidence of sinus node dysfunction. Significant differences were observed: atrial rate was lower during exercise in DDD-mode (p less than 0.01); exercise time and cumulative load increased (p less than 0.05); maximal oxygen uptake was improved (p less than 0.05). Some of these differences were less clear in a subgroup with replacement of a VVI-device by DDD-stimulation. No differences could be observed in severity of exercise-induced arrhythmias. No evidence of sinus node dysfunction was found during exercise. Reprogramming of atrial sensitivity was required in 3 patients, with reprogramming to DVI because of paroxysmal atrial fibrillation once. Two patients died within a mean follow-up period of 13 months. Sinus rhythm was present at the most recent evaluation in all patients, including the patient stimulated in the DVI mode. Physiologic stimulation is of value for elderly patients with an active life style and complete heart block. Reprogramming to another pacing mode is only seldom necessary.

Aged↗
PubMed1986

Ischemic heart disease and regional variations of socio-cultural characteristics in Belgium.

Ischemic heart disease (IHD) can be considered as a 'cultural disease'. It is surprising to see how IHD is differentially distributed in Belgium on both sides of the linguistic frontier, with higher prevalence, incidence and mortality rates in the South as compared to the North. Therefore, various socio-cultural characteristics have been under investigation in two samples of middle-aged men, in order to determine the most discriminative ones, according to the subjects' cultural belonging. The largest differences are found in the professional activities area, suggesting that stress related to profession might be responsible for the geographical distribution of the disease.

Age Factors↗
PubMed1985

[Physical activity, physical fitness and coronary disease].

The relationship between physical activity on and off the job, physical fitness and coronary artery disease was investigated in a prospective study involving 2 363 men, 40 to 55 years old. Sudden death and myocardial infarction occurred in 31 subjects during a 5-year follow-up. Preliminary data are reported. There was no significant correlation between quartiles of physical activity on and off the job and incidence of coronary events. Physical fitness was significantly inversely correlated with incidence of coronary events (p less than 0.05) and was significantly lower in the 31 new cases (p less than 0.03). Multivariate analysis showed that HDL-cholesterol, smoking and physical fitness significantly and independently discriminate between coronary prone patients and healthy subjects. We conclude that physical fitness is an independent, inverse risk indicator of new coronary events.

Adult↗
PubMed1976

Epidemiology and prevention of ventricular ectopic rhythms.

Current work of the Laboratory of Physiological Hygiene is reviewed on the epidemiology and prevention of ectopic ventricular rhythms (VPB). The evidence suggests that uniform simple VPB at rest, or exercise-induced, are prognostically important only in those having clinically manifest coronary disease. A simple rhythm strip is an effective first screen method for detecting individuals having rather frequent VPB, and frequency of VPB is correlated with complex ectopic rhythms. A multifaceted stress induction test induces VPB and does it consistently. Hygienic intervention, in which cardiac stimulants are removed and conditioning exercises given, is being tested as VPB suppressive therapy.

Adult↗