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Biomedical subjects

R Danielsen

Publications and source records attributed to R Danielsen.

At least 37 records · Page 2Linked to original sources
PubMed1988

Hemodynamic and electrocardiographic consequences of high- and low-osmolality contrast agents for left ventricular angiography.

The cardiovascular effects of two nonionic contrast agents with low osmolality (iohexol and metrizamide) were compared with one standard ionic, high-osmolality contrast agent (metrizoate) used for left ventricular (LV) angiography in patients with coronary heart disease. Metrizoate induced a marked elevation of LV end-diastolic pressure and LV systolic pressure and an increase in cardiac output after a delay of a few minutes. All these changes were significantly less severe with iohexol and metrizamide. Hypotension occurring 30 sec after LV angiography was observed only with use of metrizoate. All agents increased heart rate, but the increase after metrizoate was significantly more pronounced and prolonged. The PQ and QT interval was prolonged only by metrizoate. The subjective symptoms were significantly more marked with metrizoate than with the two other agents. Thus the new nonionic contrast agent iohexol and metrizamide produced markedly less hemodynamic and electrocardiographic disturbance than the ionic agent metrizoate.

Aged↗
PubMed1988

Left ventricular diastolic function in young long-term type 1 (insulin-dependent) diabetic men during exercise assessed by digitized echocardiography.

Digitized M-mode echocardiograms were obtained during semisupine bicycle exercise in 10 relatively young (less than 40 years) long-term (greater than or equal to 12 years) type 1 (insulin-dependent) diabetic men, without overt heart disease, and 10 controls. Recordings were done at rest and during workloads of 50 and 100 W. At rest, heart rate was similar in the groups, while at peak exercise it was higher in the diabetics whose left ventricular (LV) end-diastolic dimension was smaller at all study phases. From baseline to peak exercise the diastolic period decreased in both groups, while the LV diastolic peak rate of dimension increase, normalized for end-diastolic dimension, the rapid filling period and the LV dimension change during this period increased. The normalized peak rates of dimension increase and heart rates correlated positively in the groups. However, diabetics had a lower normalized peak rate of dimension increase after adjusting for heart rate by covariance analysis, both at rest (18%) and during peak exercise (20%). Thus, compared to controls, this well defined group of type 1 diabetic men had a consistent subclinical decrease in their peak rate of dimension increase, both at rest and during exercise. Furthermore, the peak rate of dimension increase remained lower in the diabetic subjects after normalization for their smaller end-diastolic dimension and after adjustment for their higher heart rate.

Adult↗
PubMed1988

Factors contributing to left ventricular diastolic dysfunction in long-term type I diabetic subjects.

Although non-invasive studies in type I diabetic subjects indicate left ventricular (LV) diastolic dysfunction, the contribution of borderline or mild hypertension to such changes is obscure. Thus, digitized M-mode echocardiograms were obtained in 32 (18 men) young (less than 50 years) normotensive controls and 32 (21 men) long-term (greater than or equal to 12 years) type I diabetics with blood pressures ranging from normal to hypertensive. All diabetics were without clinical heart disease, none were previously treated for hypertension or using cardioactive drugs. Heart rate, systolic and diastolic blood pressures were higher in diabetic than control subjects. Their LV end-diastolic dimension was smaller, whereas wall thickness, LV mass index and fractional shortening were similar to controls. In diabetics, however, the normalized peak filling rate was decreased and the rapid filling period fraction of diastole increased. In multivariate analysis, diabetes and LV mass independently and inversely influenced the normalized peak filling rate, while fractional shortening did so positively. Furthermore, diabetes and systolic blood pressure independently influenced the rapid filling period fraction of diastole. This study is the first to demonstrate systolic blood pressure and LV mass as independent contributors to subclinical LV diastolic abnormalities in diabetics. These findings may therefore indicate the need to treat even mild hypertension in diabetics in an effort to delay the development of cardiopathy.

Adult↗
PubMed1988

Left ventricular performance during exercise in long-term type 1 diabetic men: an echocardiographic study.

M-mode echocardiograms were recorded and digitized during semisupine bicycle exercise in 10 young (less than 40 years) long-term (greater than or equal to 12 years) type 1 diabetic men, without heart symptoms, and 10 controls. Recordings were done at rest, during workloads of 50 and 100 W and 1, 3 and 5 min post-exercise. The groups were comparable at rest. Exercise intervention caused a higher heart rate and systolic blood pressure response in the diabetics. Overall, diabetics had a smaller left ventricular (LV) end-diastolic dimension, but it did not change during exercise within either group; LV end-systolic dimensions (ESD), however, decreased in both. The fractional shortening, normalized peak shortening rate and systolic blood pressure/ESD ratio increased in both groups. However, fractional shortening was lower in the diabetics during peak exercise, while the two latter variables of LV systolic function were similar to the controls. Furthermore, fractional shortening during peak exercise remained lower in the diabetics even when adjusted for systolic blood pressure by covariance analysis. Therefore, the decreased LV performance during exercise in the diabetic subjects is most likely secondary to reduced LV diastolic filling, as indicated by their smaller end-diastolic dimension, rather than due to decreased contractility or a higher afterload.

Adult↗
PubMed1988

Limitations in assessing the severity of aortic stenosis by Doppler gradients.

Continuous wave Doppler echocardiography was performed before cardiac catheterisation in 69 consecutive patients with suspected aortic stenosis. Agreement between the maximum and the mean Doppler gradients and catheterisation gradients was good. Doppler echocardiography, however, systematically underestimated the maximum and mean gradients, particularly in the high range. Stepwise regression analysis of the small pressure difference between the two methods showed that it could not be explained by age, sex, stroke volume, differences in heart rate, ejection fraction, the presence of coronary artery disease, or severity of aortic regurgitation. There was a negative curvilinear correlation between the maximum and mean Doppler gradients and the aortic valve areas that were measured at catheterisation in patients with pure aortic stenosis. The degree of correlation decreased when patients with concomitant aortic regurgitation were included. The scatter of gradients above and below the correlation line was large and this was caused by low and high transvalvar flow. These results show that the usefulness of Doppler gradients for judging the severity of aortic stenosis, both in relation to immediate diagnosis and follow up, is severely limited if transvalvar flow is not taken into account.

Adult↗
PubMed1988

Echocardiographic decision-making for replacement surgery in mitral valve prolapse.

The clinical usefulness of M-mode echocardiography for predicting severe mitral regurgitation (MR) requiring valve replacement was assessed in 16 men and 10 women with mitral valve prolapse (MVP) as sole primary cardiac disorder. From left ventricular (LV) angiography, MR was classified as none to moderate (8 cases, group A) or severe (18 cases, group B). At echocardiography, increased LV end-diastolic and end-systolic and left atrial (LA) dimensions, corrected for body-surface area, distinguished group B from group A, with the best validities for LA and LV end-diastolic values. The mean echocardiographic LV fractional shortening and ejection fraction (EF) and the angiographic EF were similar in both groups. Echocardiographic and angiocardiographic LV EF correlated poorly, the former usually overestimating the latter. LV end-diastolic and mean pulmonary capillary wedge pressures were highest in group B, and the latter correlated with echocardiographic LA size. Mitral valve replacement was subsequently performed on 15 of the 18 group B patients. M-mode echocardiography is a valuable adjuvant to clinical assessment of MVP for predicting MR severity and for time-planning of cardiac catheterization or mitral valve surgery.

Adult↗
PubMed1988

Assessment of the left ventricular diastolic function in constrictive pericarditis by digitised M-mode echocardiography.

Digitised M-mode echocardiography was used to study the diastolic left ventricular function in ten patients with constrictive pericarditis. Each patient was matched for heart rate and stroke volume with a control patient who had normal left ventricular end-diastolic pressure and coronary arteries. All 20 patients underwent right and left cardiac catheterisation. In patients with constrictive pericarditis compared with controls, the median (range) left ventricular peak diameter lengthening rate, normalised for end-diastolic dimension, was 4.5 (2.5-8.0) s-1 and 2.9 (1.6-4.1) (p less than 0.01), and the rapid filling period fraction of diastole was 0.28 (0.18-0.37) and 0.37 (0.21-0.58) (p less than 0.05), while the mitral valve E-F slope was 20.1 (10.5-39.2) cm/s and 11.8 (7.6-14.5) (p less than 0.05), respectively. Thus, the early rate of left ventricular diameter lengthening is increased in constrictive pericarditis independent of heart rate and stroke volume, while the actual duration of the rapid filling period is decreased. These results, obtained noninvasively, extend the findings of previous invasive studies. The method may help in the difficult clinical diagnosis of constrictive pericarditis, although there is some overlap with the normal control range.

Adult↗
PubMed1988

Factors affecting suitability for coronary bypass surgery.

Factors responsible for unsuitability for bypass surgery were assessed prospectively in 324 consecutive patients with serious angina pectoris undergoing cardiac catheterization. One hundred patients were found to be unsuitable for surgery (31%). These patients usually had peripheral coronary atherosclerosis (44%), stenotic/occluded artery distributing to an infarcted (35%) or small area (25%), or reduced global left ventricular (LV) function (15%). Age over 65 years (p less than 0.05), female sex (p less than 0.05), previous myocardial infarction (p less than 0.05), 1-vessel disease (p less than 0.01) and a low LV ejection fraction (p less than 0.01) occurred more often in patients not accepted for surgery. Of the patients with 3-vessel disease 75% were referred for surgery while only 25% of patients with 1-vessel disease (p less than 0.001) Stepwise logistic regression analysis identified LV ejection fraction as an inverse predictor (p less than 0.001) and number of stenotic coronary arteries as a predictor (p less than 0.001) of suitability for surgery. Thus, peripheral coronary atherosclerosis and global LV function are the main factors determining unsuitability for coronary bypass surgery.

Adult↗
PubMed1987

Subclinical left ventricular abnormalities in young subjects with long-term type 1 diabetes mellitus detected by digitized M-mode echocardiography.

Noninvasive studies in patients with type 1 diabetes mellitus suggest subclinical left ventricular (LV) impairment, but the studies differ with regard to methods, patient selection and results. Thus, digitized M-mode echocardiograms were recorded in 24 persons younger than 50 years with long-term (more than 12 years) type 1 diabetes but without overt heart disease and in 28 control subjects. To improve accuracy, measurements were adjusted for body surface area, LV size and the influence of heart rate, as appropriate. Diabetics had a higher heart rate and systolic and diastolic blood pressure than control subjects. LV end-diastolic and stroke dimensions were smaller, duration of systole longer and preejection period/LV ejection time ratio higher than in control subjects, whereas fractional shortening and peak shortening rate were similar. In diabetics, diastole was shorter, peak filling rate was lower and the rapid filling period was prolonged, while percent filling during the rapid filling period and atrial contribution to filling were higher. Thus, in a well defined study population of relatively young persons with long-term type 1 diabetes, subclinical LV systolic and diastolic dysfunction were found. The diastolic abnormalities suggest reduced LV compliance, while those in systole may be secondary to an increased afterload or decreased myocardial contractility.

Adult↗
PubMed1987

High occurrence of mitral valve prolapse in cardiac catheterization patients with pure isolated mitral regurgitation.

The aetiological spectrum of angiographically verified pure isolated mitral regurgitation (MR) was studied in 48 consecutive adult patients (35 males). Severe MR was found in 35 patients (73%) and moderate MR in 13 patients (27%). Mitral valve prolapse (MVP) syndrome was found in 21 patients (44%). These were younger than the rest of the study population (55 +/- 13 vs. 62 +/- 6 years, p less than 0.05) and 15 (71%) of them were men. Endocarditis and chordal rupture occurred in 19% and 43% of the MVP patients. Sixteen patients (33%) had MR secondary to myocardial infarction while only three patients (6%) had MR of rheumatic aetiology. Bacterial endocarditis, hypertensive heart disease, hypertrophic obstructive cardiomyopathy and mitral annulus calcification were less frequently found. Mitral valve replacement was done in 20 (57%) of the patients with severe MR and MVP was the underlying disease in 15 (75%) of these patients. In conclusion, MVP is a frequent cause of pure isolated MR and of mitral valve replacement. In contrast to the preponderance of young females amongst MVP patients in population surveys, most of the MVP patients with MR in this study are middle-aged and elderly men.

Adult↗
PubMed1987

Digitized echocardiographic measurements of left ventricular function: reproducibility and physiological factors influencing the method.

The variability of digitized M-mode echocardiographic measurements and the potential influence of physiological factors on these was studied in 28 relatively young (less than 50 years) healthy subjects. All had heart rates within the normal range. Echocardiographic recordings were standardized in the end-expiratory phase. The coefficients of variation for direct echocardiographic measurements were less than or equal to 6% and for most digitized time derived variables less than or equal to 15%. They were generally greater for inter- than for intracycle comparisons. In systole, the peak shortening rate and the time period from the start of systole to the point of peak shortening rate showed the best reproducibility, while in diastole the peak filling rate, the rapid filling period and the percentage filling during the same period. In multivariate analysis, age and heart rate were found to influence the digitized derived systolic but not the diastolic variables. Their influence, however, on digitized echocardiographic measurements may vary with study subjects selection and should be considered when interpreting results.

Adult↗
PubMed1983

Prognostic factors and retinopathy in type 1 diabetics in Iceland.

Prognostic factors, particularly those related to metabolic control, were analysed individually over a period of 12 months prior to fundus photography in 149 type 1 (insulin-dependent, ketosis-prone) diabetics in Iceland. Patients without retinopathy in their first 20 years of diabetes visited the Diabetic Clinic significantly more frequently than those with retinopathy (p less than 0.05). Mean blood sugar values and mean per cent body weight did not differ between patients with or without retinopathy. Few between patients with or without retinopathy. Few patients were obese. In patients with 5-9 years' duration of diabetes, retinopathy was first seen after 7.7 +/- 0.3 years (mean +/- SEM). Those with retinopathy were significantly older at the time of the diagnosis of diabetes than those without eye lesions (p less than 0.025), a tendency also noted in those with 10-19 years' duration (p less than 0.10). Conversely, patients without retinopathy after diabetes for 20 years or more were significantly older at the time of diagnosis (p less than 0.02). They used significantly less insulin daily than those with retinal lesions (p less than 0.005) and 70% were females. Subsequently, a significant (p less than 0.047) male excess was found to characterize a group of patients with proliferative retinopathy.

Adolescent↗
PubMed1982

Prevalence of retinopathy and proteinuria in type 1 diabetics in Iceland.

The prevalence of retinopathy and proteinuria was assessed in 212 and 230 type 1 diabetics in Iceland respectively. They represent 78% and 84% of all such patients identified in the country. Retinopathy was present in 33.5%, background lesions only in 27.4% and more severe retinopathy in 6.1%. After 5-9 years of diabetes (mean 6.9) the prevalence of retinopathy was 18.8%, including 2.1% proliferative, and rose to 76.7% after 20 years or more of diabetes (mean 26.7), including 16.2% in the proliferative stage. Blindness was found in 2.4% of the patients. Diabetics diagnosed at the age of 0-19 years had a lower prevalence of retinopathy during their first 20 years of diabetes than those diagnosed later in life (p less than 0.05). Proteinuria was present in 14%, intermittent in 10% and continuous in 4%. After 10 years or more of diabetes (mean 19.3) the prevalence of intermittent and continuous proteinuria was 13.0% and 8.3%, respectively.

Adolescent↗