Biomedical subjects

M C de Bruyne

Publications and source records attributed to M C de Bruyne.

14 recordsLinked to original sources

PubMed2002

[Cardiovascular risk factors. II. Signs of vascular damage: practical implications].

In recent years, an increasing amount of information has become available on new indicators of cardiovascular damage, their determinants and the value of these indicators in the prediction of the development of cardiovascular disease. These indicators include carotid intima-media thickness, ECG characteristics, endothelial function and the measurement of coronary calcium. These indicators are currently used predominantly in cardiovascular disease research. At present, only limited information is available as to whether these indicators are useful in clinical practice for estimating the absolute risk of cardiovascular disease in an individual. The relative value of these newer indicators compared to the routinely collected risk factor information such as medical history, lifestyle, anthropometric variables, blood pressure and lipids is also not yet well established. The recent Dutch guidelines for the initiation of treatment with blood pressure lowering and lipid lowering drugs as a function of the absolute risk of cardiovascular disease within 10 years for the individual patient point toward the urgent necessity for research in the area of new risk indicators of vascular damage.

Cardiovascular Diseases↗

PubMed2002

Factors associated with switching from oral hypoglycaemic agents to insulin therapy.

BACKGROUND: The aim of our study was to determine which factors are associated with switching from oral hypoglycaemic agents to insulin therapy in patients with type 2 diabetes mellitus in general practice. METHODS: Longitudinal, observational study in a Dutch general healthcare centre. All pharmacologically treated patients with type 2 diabetes mellitus were included (n = 152). Comorbidity, laboratory results and medication use were obtained from the general practitioners' files. RESULTS: A total of 31 (20.4%) patients switched from oral hypoglycaemic agents to insulin therapy; they were significantly younger at the onset of diabetes, 50.5 versus 57.7 years. Fasting blood glucose levels and HbA(1c) values were significantly higher after the switch compared with patients on oral treatment, 10.0 mmol/l versus 8.4 mmol/l and 8.8% versus 7.9%, respectively. Concerning comorbidity, they suffered more frequently from acute myocardial infarction, lipid disorders, depression, retinopathy and atrial fibrillation. Cardiovascular disease in general was more often present in patients who switched over to insulin, 77.4% versus 52.9% (OR 3.1; CI 1.2-7.6). CONCLUSIONS: Patients who switch over to insulin therapy are younger at diagnosis, suffer from more health problems besides diabetes, especially cardiovascular disease, and have worse metabolic control, compared with users of oral hypoglycaemic agents.

Administration, Oral↗

PubMed1999

Both decreased and increased heart rate variability on the standard 10-second electrocardiogram predict cardiac mortality in the elderly: the Rotterdam Study.

Decreased heart rate variability has been associated with an adverse prognosis in patients after myocardial infarction. Studies carried out in the population at large show contradictory results. The authors examined the association between heart rate variability on a standard 10-second electrocardiogram and cardiac and all-cause mortality in the Rotterdam Study, a population-based cohort study of men and women aged > or =55 years, using data collected between 1990 and 1996 (mean follow-up = 4 years). Heart rate variability, taken as the standard deviation of normal R-R intervals (SDNN), was computed by means of the Modular ECG Analysis System. After exclusion of subjects with arrhythmia and those with fewer than six normal R-R intervals, the study population consisted of 2,088 men and 3,184 women. Cox's proportional hazards model was used to examine the age- and sex-adjusted risk for cardiac, noncardiac, and total mortality in relation to quartiles of SDNN, using the third quartile of SDNN as the reference category. Subjects in the lowest quartile of SDNN relative to those in the third quartile had an 80 percent age- and sex-adjusted increased risk for cardiac mortality (hazard ratio = 1.8; 95% confidence interval: 1.0, 3.2). Interestingly, for subjects in the highest quartile of SDNN, an even more pronounced risk for cardiac mortality was present (hazard ratio = 2.3; 95% confidence interval: 1.3, 4.0). Additional adjustment for possible confounders did not materially change the risk estimates. The authors conclude that heart rate variability measured on the standard 10-second electrocardiogram can be used to identify older men and women with an increased risk for cardiac mortality. In the elderly, increased heart rate variability is an even stronger indicator of cardiac mortality than decreased heart rate variability. Further studies are needed to confirm these findings and to elucidate their physiologic meaning.

Aged↗

PubMed1999

Prolonged QT interval predicts cardiac and all-cause mortality in the elderly. The Rotterdam Study.

AIMS: To examine the association between heart-rate corrected QT prolongation and cardiac and all-cause mortality in the population-based Rotterdam Study among men and women aged 55 years or older and to compare the prognostic value of the QT interval, using different formulas to correct for heart rate. METHODS AND RESULTS: After exclusion of participants with arrhythmias or bundle branch block on the ECG, the study population consisted of 2083 men and 3158 women. The QT interval was computed by the Modular ECG Analysis System (MEANS). Data were analysed using Cox' proportional hazards model. Participants in the highest quartile of the heart-rate corrected QT interval had about a 70% age- and sex-adjusted increased risk for both all-cause mortality (hazard ratio (HR) 1.8; 95% CI:1.3-2.4) and cardiac mortality (HR 1.7; 95% CI:1.0-2.7) compared to those in the lowest quartile. In women, the increased risk associated with prolonged QT for cardiac death was more pronounced than in men. These risk estimates did not change after adjustment for potential confounders, including history of myocardial infarction, hypertension and diabetes mellitus. CONCLUSION: A prolonged heart-rate corrected QT interval is an independent predictor for cardiac and all-cause mortality in older men and women. The risk associated with prolonged QT is hardly affected by the heart-rate correction formula used.

Age Distribution↗

PubMed1999

Prevalence of heart failure and left ventricular dysfunction in the general population; The Rotterdam Study.

AIMS: To determine the prevalence of heart failure and symptomatic as well as asymptomatic left ventricular systolic dysfunction in the general population. METHODS AND RESULTS: In 5540 participants of the Rotterdam Study (age 68.9+/-8.7 years, 2251 men) aged 55-95 years, the presence of heart failure was determined by assessment of symptoms and signs (shortness of breath. ankle oedema and pulmonary crepitations) and use of heart failure medication. In 2267 subjects (age 65.7+/-7.4 years, 1028 men) fractional shortening was measured. The overall prevalence of heart failure was 3.9% (95% CI 3.0+/-4.7) and did not differ between men and women. The prevalence increased with age, with the exception of the highest age group in men. Fractional shortening was higher in women and did not decrease appreciably with age. The prevalence of left ventricular systolic dysfunction (fractional shortening <=25%) was approximately 2.5 times higher in men (5.5%, 95% CI 4.1-7.0) than in women (2.2%, 95% CI 1.4-3.2). Sixty percent of persons with left ventricular systolic dysfunction had no symptoms or signs of heart failure at all. CONCLUSIONS: The prevalence of heart failure is appreciable and does not differ between men and women. The majority of persons with left ventricular systolic dysfunction can be regarded as having asymptomatic left ventricular systolic dysfunction.

Age Factors↗

PubMed1998

T axis as an indicator of risk of cardiac events in elderly people.

BACKGROUND: The T axis was postulated to be a general marker of repolarisation abnormality, indicative of subclinical myocardial damage. The aim of this investigation was to assess the prognostic importance of the T axis for fatal and non-fatal cardiac events, in a prospective cohort study of men and women aged 55 years and older. METHODS: 2352 men and 3429 women from the population-based Rotterdam Study took part in the study. Electrocardiograms were done, and T axes were categorised as normal, borderline, or abnormal. Data were analysed with Cox's proportional-hazards models; adjustment for age and sex was done where appropriate. FINDINGS: During 3-6 (mean 4) years of follow-up of the 5781 participants, 165 (2.9%) fatal and 192 (3.3%) non-fatal cardiac events occurred. Participants with an abnormal T axis (n=609) had an increased risk of cardiac death (hazard ratio 3.9 [95% CI 2.8-5.6]), sudden cardiac death (4.4 [2.6-7.4]), non-fatal cardiac events (2.7 [1.9-3.9]), and combined fatal or non-fatal cardiac events (3.2 [2.5-4.1]); p<0.001 for each. Additional adjustment for established cardiovascular risk factors resulted in lower, but still significant risk for all endpoints. The risk associated with an abnormal T axis was higher than those for any other cardiovascular risk factor. Additional subgroup analyses indicated that the risk of cardiac death was not substantially modified by age, sex, or history of myocardial infarction. INTERPRETATION: The T axis is a strong and independent risk indicator of fatal and non-fatal cardiac events in the elderly.

Aged↗

PubMed1998

QTc dispersion predicts cardiac mortality in the elderly: the Rotterdam Study.

BACKGROUND: Increased QTc dispersion has been associated with an increased risk for ventricular arrhythmias and cardiac death in selected patient populations. We examined the association between computerized QTc-dispersion measurements and mortality in a prospective analysis of the population-based Rotterdam Study among men and women aged > or = 55 years. METHODS AND RESULTS: QTc dispersion was computed with the use of the Modular ECG Analysis System as the difference between the maximum and minimum QTc intervals in 12 and 8 leads (ie, the 6 precordial leads, the shortest extremity lead, and the median of the 5 other extremity leads). After exclusion of those without a digitally stored ECG, the population consisted of 2358 men and 3454 women. During the 3 to 6.5 years (mean, 4 years) of follow-up, 568 subjects (9.8%) died. The degree of QTc dispersion was categorized into tertiles. Data were analyzed using the Cox proportional hazards model, with adjustment for age. For QTc dispersion in 8 leads, those in the highest tertile relative to the lowest tertile had a twofold risk for cardiac death (hazard ratio, 2.5; 95% confidence interval [CI], 1.6 to 4.0) and sudden cardiac death (hazard ratio, 1.9; 95% CI, 1.0 to 3.7) and a 40% increased risk for total mortality (hazard ratio, 1.4; 95% CI, 1.2 to 1.8). Additional adjustment for potential confounders, including history of myocardial infarction, hypertension, and overall QTc, did not materially change the risk estimates. Hazard ratios for QTc dispersion in 12 leads were comparable to those found for QTc dispersion in 8 leads. CONCLUSIONS: QTc dispersion is an important predictor of cardiac mortality in older men and women.

Age Factors↗

PubMed1998

Reproducibility of computerized ECG measurements and coding in a nonhospitalized elderly population.

The standard 12-lead electrocardiogram (ECG) is used in many epidemiologic studies to diagnose and predict cardiovascular disease. In view of this, knowledge about the reproducibility of ECG measurements and coding is essential. Minute-to-minute, day-to-day, and year-to-year variability of ECG measurements, composite scores, and Minnesota Code classification were assessed by use of a computer program, in 101 nonhospitalized elderly men and women. Interval ECG measurements were more reproducible than amplitude measurements. The best reproducibility was found for the overall QTc interval (coefficient of variation 3.1%, 4.0%, and 5.2% for the minute-to-minute, day-to-day, and year-to-year groups, respectively) and the poorest was found for the Cardiac Infarction Injury Score (coefficient of variation 67.1%, 78.5%, and 94.3%, respectively). Minnesota Code discrepancies occurred in 16%, 19%, and 22% of the ECGs in the minute-to-minute, day-to-day, and year-to-year groups, respectively. Reproducibility within specific code categories was much better. Overall, variability tended to increase with time. In the routine setting, electrode positioning had relatively little effect on total variability.

Aged↗

PubMed1998

T-loop morphology as a marker of cardiac events in the elderly.

ST-T wave changes of electrocardiographic (ECG) leads have long been recognized as predictors of future cardiac events, but they only imperfectly characterize T-loop morphology. Using vectorcardiographic (VCG) parameters, we investigated the predictive value of T-loop abnormality for fatal and nonfatal cardiac events in a prospective cohort study among 5,815 elderly. Separately, the predictive value of an easily obtainable T-loop parameter, the T axis, was also assessed. Measurements were determined by a computer program, using VCGs reconstructed from the standard 12-lead ECGs. During the 3 to 6 (mean 4) years of follow-up, 166 fatal and 193 nonfatal cardiac events occurred. Subjects with an abnormal T-loop morphology had increased risks for fatal cardiac events (hazard ratio 4.3; 95% CI 3.0-6.4) and nonfatal cardiac events (3.0; 1.9-4.8). Risks associated with an abnormal T axis alone were only slightly lower. Additional adjustment for established cardiovascular risk indicators resulted in lower, but still highly significant risks. Both T-loop and T-axis abnormalities appear to be strong, independent risk indicators of cardiac events in the elderly.

Aged↗

PubMed1997

Prolonged QT interval: a tricky diagnosis?

Prolonged heart-rate adjusted QT intervals on the electrocardiogram (ECG) are associated with an increased risk for coronary heart disease and sudden death. However, the diagnosis of the prolonged QT interval is hampered by lack of standards. We studied variations in the prevalence of prolonged QT, based on different common definitions, in a large nonhospitalized population, and compared our results with other studies applying the same definitions. The study population consisted of 2,200 men and 3,366 women participants of the Rotterdam Study, > or =55 years old. The QT interval was computed by our Modular ECG Analysis System (MEANS). Three different formulas to adjust QT for heart rate were used: Bazett's formula (QTc), a linear regression equation (QTlr), and the QT index (QTI). Prolonged QT occurred frequently in both men and women, and its prevalence increased with age. Women had longer heart-rate adjusted QT intervals than men (mean QTc 433 ms vs 422 ms), and mean values for QTlr were lower than for QTc (mean QTlr 422 ms in women and 412 ms in men). Prevalence was highest for prolonged QTlr (31% in men and 26% in women) and lowest for prolonged QTI (6% in men and 9% in women). Comparison with other studies applying the same correction formulas showed large discrepancies in prevalence estimates of prolonged QTc and QTlr, and to a lesser degree of prolonged QTI, possibly due to differences in measurement techniques. Future research is needed to relate QT interval to prognosis, to obtain measurement technique specific reference values of heart-rate adjusted QT measurements, and to obtain age- and sex-specific threshold values for prolonged QT. Such data are needed to use the QT interval with confidence.

Aged↗

PubMed1997

Diagnostic interpretation of electrocardiograms in population-based research: computer program research physicians, or cardiologists?

We assessed the performance of diagnostic electrocardiogram (ECG) interpretation by the computer program MEANS and by research physicians, compared to cardiologists, in a physician-based study. To establish a strategy for ECG interpretation in health surveys, we also studied the diagnostic capacity of three scenarios: use of the computer program alone (A), computer program and cardiologist (B), and computer program, research physician, and cardiologist (C). A stratified random sample of 381 ECGs was drawn from ECGs collected in the Rotterdam Study (n = 3057), which were interpreted both by a trained research physician using a form for structured clinical evaluation and by MEANS. All ECGs were interpreted independently by two cardiologists; if they disagreed (n = 175) the ECG was judged by a third cardiologist. Five ECG diagnoses were considered: anterior and inferior myocardial infarction (MI), left and right bundle branch block (LBBB and RBBB), and left ventricular hypertrophy (LVH). Overall, sensitivities and specificities of MEANS and the research physicians were high. The sensitivity of MEANS ranged from 73.8% to 92.9% and of the research physician ranged from 71.8% to 96.9%. The specificity of MEANS ranged from 97.5% to 99.8% and of the research physician from 96.3% to 99.6%. To diagnose LVH, LBBB, and RBBB, use of the computer program alone gives satisfactory results. Preferably, all positive findings of anterior and inferior MI by the program should be verified by a cardiologist. We conclude that diagnostic ECG interpretation by computer can be very helpful in population-based research, being at least as good as ECG interpretation by a trained research physician, but much more efficient and therefore less expensive.

Bundle-Branch Block↗

PubMed1997

Prevalence, determinants, and misclassification of myocardial infarction in the elderly.

We evaluated the prevalence, determinants, and misclassification of different types of myocardial infarction in 3,272 men and women age 55 years or older. We defined self-reported myocardial infarction with electro-cardiographic evidence as "typical myocardial infarction." We defined self-reported myocardial infarction without electrocardiographic evidence, but verified with additional clinical information, as "non-Q-wave myocardial infarction." Finally, we defined myocardial infarction detected by electrocardiogram that was not self-reported as "silent myocardial infarction," after verification of absence of symptoms. Overall, the prevalence of typical myocardial infarction was 4.1% [95% confidence interval (CI) = 3.5-4.9], of non-Q-wave myocardial infarction 2.8% (95% CI = 2.2-3.4), and of silent myocardial infarction 3.9% (95% CI = 3.2-4.5). Silent myocardial infarction was more prevalent in women, hypertensives, cigarette smokers, and those with higher post-load blood glucose. Self-reported myocardial infarction without electrocardiographic characteristics could be verified as myocardial infarction by means of additional clinical information in 56% of the cases. We conclude that myocardial infarction occurs frequently in the elderly without typical symptoms or electrocardiographic changes. As all these manifestations of myocardial infarction convey an increased risk of symptomatic heart disease or death, they require further attention. Misclassification due to limited sources of information can be considerable and should be taken into account in the design and interpretation of epidemiologic studies.

Age Distribution↗

PubMed1997

Vascular determinants of epilepsy: the Rotterdam Study.

PURPOSE: To investigate the relation between vascular determinants and epilepsy in an elderly population. METHODS: This is a cross-sectional, community-based, case-control study. The total study population was comprised of 4,944 subjects, 65 of whom had epilepsy which conformed to International League Against Epilepsy (ILAE) criteria. Vascular determinants that were evaluated included a history of stroke or myocardial infarction, peripheral vascular disease, hypertension, serum total cholesterol and left ventricular hypertrophy. Multivariate logistic regression analysis was used to calculate prevalence odds ratios (OR), adjusted for age and gender, as a measure of the strength of the associations. RESULTS: A history of stroke was strongly associated with lifetime epilepsy (OR 3.3; 95% CI [Confidence Interval] 1.3-8.5), as well as with late-onset epilepsy (OR 3.1; 95% CI 0.9-10.6). All vascular determinants were associated with lifetime epilepsy and late-onset epilepsy, with odds ratios >1. When stroke patients were excluded, the odds ratios were statistically significant for the relationships between total cholesterol and late-onset epilepsy (OR 1.3, 95% CI 1.0-1.6) and left ventricular hypertrophy and late-onset epilepsy (OR 2.9, 95% CI 1.0-8.6). Furthermore, presence of any of these vascular indicators was twice as common among subjects with late-onset epilepsy as compared with subjects without epilepsy (OR 2.0, 95% CI 0.9-4.2), and this was statistically significant when stroke patients were excluded (OR 2.1, 95% CI 1.0-4.7). CONCLUSIONS: These results suggest that there may be a relationship between vascular factors and the risk of late-onset epilepsy, apart from the relationship that exists through clinically overt stroke.

Age Factors↗

PubMed1997

Atrial fibrillation and dementia in a population-based study. The Rotterdam Study.

BACKGROUND AND PURPOSE: Atrial fibrillation is a frequent disorder in the elderly and a known risk factor for cerebrovascular stroke. We investigated the association of atrial fibrillation with dementia and cognitive impairment in a large cross-sectional, population-based study in the elderly. METHODS: Of the 6584 participants in the Rotterdam Study aged 55 to 106 years, detailed information on dementia status and ECG abnormalities was available. Dementia was diagnosed in three phases. First, participants were screened. Screen-positive subjects were tested further. Those with possible dementia underwent an extensive diagnostic workup. Dementia and dementia subtypes were diagnosed according to prevailing criteria. Cognitive impairment was defined as a Mini-Mental State Examination test score of < 26 points for a nondemented subject. RESULTS: Atrial fibrillation was diagnosed in 195, dementia in 276, and cognitive impairment in 635 subjects. We found significant positive associations of atrial fibrillation with both dementia and impaired cognitive function (age- and sex-adjusted odds ratios, 2.3 [95% confidence interval, 1.4 to 3.7] and 1.7 [95% confidence interval, 1.2 to 2.5]), respectively). The strongest association was found not for vascular dementia but rather for Alzheimer's disease with cerebrovascular disease. The associations were stronger in women, and the relation with dementia was more pronounced in the relatively younger elderly. A history of stroke in subjects with atrial fibrillation could not account for these associations. CONCLUSIONS: Dementia and subtypes Alzheimer's disease and vascular dementia may be related to atrial fibrillation even if no clinical stokes have occurred.

Age Factors↗