Biomedical subjects

H Kelbaek

Publications and source records attributed to H Kelbaek.

At least 55 records · Page 3Linked to original sources

PubMed1992

Leucocyte scintigraphy to localize inflammatory activity in ulcerative colitis and Crohn's disease.

The validity of using autologous leucocytes labelled with technetium -99m hexamethyl-propyleneamine-oxine (Tc-HMPAO) for scintigraphy in inflammatory bowel disease was evaluated in 12 patients with clinically active ulcerative colitis (UC) and 10 with Crohn's disease (CD). Colonoscopy and biopsy were used as reference. Scintigrams taken 1 h and 3 h after leucocyte reinjection were evaluated blindly by two independent observer groups. Full agreement was found in 11 of 12 UC patients when compared with colonoscopy but in only 3 of 10 CD patients. Segments with agreement in CD patients often showed neutrophilic granulocyte infiltration at biopsy. The judgements of clinicians and physiologists differed for only 2 of totally 70 UC segments but for 13 of 59 CD segments (kappa, 0.94 and 0.52). It is concluded that Tc-HMPAO scintigraphy might be an alternative to colonoscopy in the control of disease extent in UC. In CD patients the technique might warn about infections complications.

Adult↗

PubMed1991

Effects of atropine on left ventricular volumes and ejection and filling rates at rest and during exercise.

1. The influence of the parasympathetic nervous system on left ventricular function including ejection and filling rates was studied by radionuclide cardiography in eight healthy young men at rest and during upright exercise. 2. After parasympathetic blockade induced by atropine, the mean heart rate (HR) at upright rest increased from 67 to 114 beats min-1, cardiac output (CO) from 4.05 to 5.17 1 min-1 (both P less than 0.001), and the diastolic blood pressure by 13 mm Hg (P less than 0.01). 3. Stroke volume (SV), left ventricular end diastolic and end systolic volume all decreased significantly after atropine. The relative ejection time increased from 0.33 to 0.51 of the cardiac cycle length (P less than 0.001), and the appropriate ejection and filling rates increased by 13% (P less than 0.05) and 147% (P less than 0.001), respectively. Haemodynamic changes in the supine position were virtually the same. 4. During exercise atropine increased HR from 115 to 146 beats min-1 (P less than 0.001) and CO by 12% (P less than 0.05), whereas SV decreased by 12% (P less than 0.05) and the systolic blood pressure by 16 mm Hg (P less than 0.001). Changes in ejection and filling rate of the left ventricle were of the same nature as those found at rest. 5. Thus apart from its HR limiting properties, secondary effects of parasympathetic nervous tone are dilatation of the left ventricle and enhancement of ejection, effects that are counteracted by atropine.

Adult↗

PubMed1991

Impaired left-ventricular function in insulin-dependent diabetic patients with increased urinary albumin excretion.

Cardiac function was studied in 30 patients with insulin-dependent diabetes mellitus. Three groups, matched for age and diabetes duration, were defined as: group I (n = 10), normal urinary albumin excretion less than 30 mg 24 h-1; group II (n = 10), incipient diabetic nephropathy (urinary albumin excretion in the range of 30-300 mg 24 h-1); and group III (n = 10), clinical diabetic nephropathy (urinary albumin excretion greater than 300 mg 24 h-1). Ten non-diabetic subjects matched for sex and age served as controls. The left-ventricular end-diastolic volume measured by radionuclide cardiography was, at rest and during exercise, lower in group II and III compared with controls (p less than 0.05), while intermediate values were found in group I. The cardiac output was similar in the control group and group I; it was reduced, but not significantly so (p = 0.10), in group III and was significantly lower in group II (p less than 0.05). Stroke volume was also lower in group II and III than in controls (p less than 0.05), but not so in group I. These differences could not be explained by differences in metabolic control, blood pressure, blood volume status, degree of autonomic neuropathy or frequency of coronary heart disease. Our results might suggest that insulin-dependent diabetic patients with slightly but persistently elevated urinary albumin excretion have reduced diastolic compliance of the left-ventricle leading to impaired cardiac performance.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMed1991

Effects of acute cardioselective and non-selective beta-adrenergic blockade on left-ventricular volumes and vascular resistance at rest and during exercise.

The effects of intravenous metoprolol and propranolol on left-ventricular performance were studied by radionuclide cardiography in eight healthy young men at rest and during exercise. At rest, a fall of 7 to 10 mmHg was recorded in systolic blood pressure after both drugs (p less than 0.05). The decrease in cardiac output entirely ascribed to relative bradycardia was 18% after propranolol (p less than 0.01) compared with 6% after metoprolol (p less than 0.05). Left-ventricular volumes did not change at rest. Systemic vascular resistance increased by 14% after metoprolol and by 28% after propranolol (both p less than 0.05). During submaximal bicycle exercise the systolic blood pressure fell by 15 mmHg after both drugs (p less than 0.05). The reduction in exercise heart rate was 17 beats min-1 and 18 beats min-1 (both p less than 0.01), but propranolol reduced cardiac output by 18% (p less than 0.01) compared with 5% (p less than 0.05) after metoprolol, reflecting a reduction in stroke volume induced only by non-selective blockade. A more pronounced left-ventricular end-diastolic dilatation during exercise was allowed by metoprolol and the fall in the exercise ejection fraction was, therefore, smaller after this drug. Concomitantly, the calculated systemic vascular resistance was increased only 6% by metoprolol (p less than 0.05) compared with a 29% increase by propranolol (p less than 0.01). These findings suggest that, at least in healthy subjects, metoprolol is superior to propranolol in the ability to limit adverse cardiovascular changes.

Adrenergic beta-Antagonists↗

PubMed1991

Acute cardiovascular effects of insulin in hyperglycaemic type I diabetics.

Cardiovascular responses to high-dose (0.100 IE kg-1 h-1) and low-dose insulin infusion (0.005-0.01 IE kg-1 h-1) were examined in eight hyperglycaemic, resting type I diabetics. Mean blood glucose dropped from 15.9 to 7.1 mmol l-1 and from 14.4 to 12.6 mmol l-1, respectively, during 1 h. Blood pressure and heart rate did not change. There were no significant changes in absolute or relative left ventricular volumes, the 95% confidence interval (CI) for the difference between the doses in left ventricular ejection fraction was -6 to 8%. Calf blood volume increased on high-dose insulin (p = 0.05, CI for the difference over low-dose insulin 0.0 to 4.6 ml 100 ml-1 tissue). Blood flow increased with 1.6 ml 100 ml-1 tissue min-1 with high-dose insulin and with 0.6 ml 100 ml-1 tissue min-1 with low-dose (CI for the difference -0.5 to 3.4). Noradrenaline increases were small and there was no difference between the doses (p = 0.47).

Adult↗

PubMed1990

Doctors' requirements for reproducibility of diagnostic information.

Two radiologists independently assessed 100 leg vein phlebograms for the presence or absence of deep venous thrombosis. In a subsequent questionnaire, 66 physicians were asked to state the level of agreement they would require to use conventional phlebography in their diagnostic decisions, and whether they would reduce their requirements if the phlebographic technique were made less painful and less expensive. The responses indicated physicians' requirements for reproducibility of a well-known routine diagnostic method may be unrealistic, and that physicians do not consider the inconvenience of an examination to the patient or its cost in setting their requirements for diagnostic precision.

Adult↗

PubMed1990

Cardiopulmonary complications in high-risk surgical patients: the value of preoperative radionuclide cardiography.

In a prospective study we examined the strength of association between preoperative left ventricular performance measured by radionuclide cardiography in patients with cardiac or pulmonary insufficiency (high-risk patients) and cardiopulmonary complications associated with anaesthesia and surgery. Detailed pre-, intra- and postoperative data collected for 7306 anaesthetized patients were included in the study. One hundred and thirty-one patients (1.8%) were classified as high-risk patients, and 95 patients were examined with radionuclide cardiography. The results demonstrated a 58% incidence of cardiovascular complications for high-risk patients when the left ventricular ejection fraction (LVEF) was abnormal (less than 50% or greater than 70%) compared with 12% when LVEF was normal (50-70%). In addition, high-risk patients with left ventricular end-diastolic volume (LVEDV) greater than 140 ml developed cardiovascular complications in 37% of the cases. Patients admitted to major surgery with LVEF less than 50 or greater than 70% were at greater risk than patients with LVEF = 50-70% as demonstrated by a significant increase in the total incidence of cardiopulmonary complications, 70% vs. 17%. It is appropriate to measure LVEF in patients admitted for major surgery who have an increased risk of cardiopulmonary complications as clinically evidenced by heart failure or severe ischaemic heart disease. As the predictive information given by LVEDV was less than that given by LVEF, there are no clinical reasons for measurement of LVEDV.

Adult↗

PubMed1989

[Long-term survival of patients with angina pectoris admitted with suspected myocardial infarction].

The long-term survival in 240 patients with severe angina pectoris was assessed. All of these patients had been admitted on account of suspected acute myocardial infarction but this diagnosis could be excluded. The mean age was 64.5 years, range 37-87 years. The one, five and ten year survivals were 83.9, 58.5 and 37.2%, respectively. During the first year after discharge, the risk of dying was 16% and decreases to 9% during the subsequent nine years. By means of univariat analysis, previous AMI and duration of ischaemic heart disease were shown to be of prognostic importance. The variables during hospitalization which were found to provide prognostic information were those concerning congestive heart failure, ventricular ectopic activity and type of angina pectoris. After inclusion of age and previous manifestations of ischaemic heart disease, only variables describing congestive heart failure and ventricular ectopic activity were found to provide prognostic information, by stepwise multivariate analysis.

Adult↗

PubMed1989

Central hemodynamic changes after ingestion of a meal in patients with coronary artery disease.

Thirty-six patients with coronary artery disease participated in a controlled trial of the influence of food intake on central hemodynamic parameters determined noninvasively by radionuclide cardiography. Stroke volume increased considerably (23%) and heart rate was slightly higher (8%) half an hour after the meal, whereas the elevated cardiac output two hours postprandially could be ascribed entirely to relative tachycardia. No significant hemodynamic changes occurred in the patients who fasted. That the left ventricular ejection fraction was increased postprandially (3% to 4%) indicated that food intake had positive inotropic as well as chronotropic effects on the ischemic heart, even in heart failure. Afterload reduction and increased sympathetic nervous activity contribute to the changes, but the primary mechanism may be a change in resistance and blood flow in the intestinal vascular bed involved in digestion.

Coronary Disease↗

PubMed1989

A new 99mTc-red blood cell labeling procedure for cardiac blood pool imaging: clinical results.

The first clinical results of a new 99mTc-red blood cell labeling procedure avoiding cell centrifugation are presented. One ml heparinized blood samples were incubated with small amounts of a stannous kit. By titration studies, ideal quantities of sodium hypochlorite for oxidation of extracellular tin and of EDTA as stabilizer of the label were found. The Cl- concentration and pH of the labeled blood were acceptable, and EDTA increased labeling yield and stability determined in vitro by a few percent. The new procedure gave a slightly higher labeling yield than a current technique using centrifugation of cells. Labeling efficiency expressed as cell bound/total activity was 96.6% +/- 1.3% in healthy subjects and 95.5% +/- 2.2% in cardiac patients and remained high for 2 h after reinjection. The biological halflife of labeled cells following the new procedure was 11-12 h rendering it suitable for serial determinations of radionuclide cardiography.

Adult↗

PubMed1989

Forearm oxygen uptake during maximal forearm dynamic exercise.

This study was undertaken in an attempt to determine the maximal oxygen uptake in a small muscle group by measuring directly the oxygen expenditure of the forearm. Five healthy medical students volunteered. The subjects' maximal forearm work capacity was determined on a spring-loaded hand ergometer. Exercise was continued until exhaustion by pain or fatigue. Two weeks later intra-arterial and intravenous catheters were placed in the dominant arm. Blood samples for measurement of oxygen concentration were collected via the catheters. Forearm blood flow was measured by means of the indicator dilution technique. Oxygen uptake was determined according to the Fick principle. The forearm oxygen uptake attained at maximal work loads was a mean of 201 (SD +/- 56) mumol.min-1.100 ml-1. It was impossible at maximal exercise to discern a plateau of the oxygen uptake curve in relation to work output. It is suggested that a plateau in the oxygen uptake curve is not a useful criterion for maximal oxygen uptake in a small muscle group. Skeletal muscle may have an unused capacity for oxygen consumption even at maximal exercise intensity where muscle work cannot be continued due to muscle pain and fatigue.

Adult↗

PubMed1989

The value of the left ventricular ejection fraction in the treatment of angina pectoris following acute myocardial infarction: a randomized double blind study.

Radionuclide determination of left ventricular ejection fraction was performed at hospital discharge and one month later in 60 patients who had suffered acute myocardial infarction. At the first determination, the patients were randomized into two groups. In the first group, the cardiologist who cared for the patients was provided with the result of the determination of the ejection fraction whereas, in the second group, the result was withheld. At a 'blinded' evaluation two months after hospital discharge, 7 of those patients (24%) from the group where the cardiologist knew the ejection fraction and 11 of the patients (38%) in whom this result was withheld complained of angina pectoris on exertion (ns). The medication of the patients did not differ in the two groups. No significant difference was found in the values of the ejection fraction in patients with and without angina pectoris. In this controlled study, we were not able to document a clinical effect by routinely determinating left ventricular ejection fraction in patients with acute myocardial infarction in the treatment of angina pectoris.

Adrenergic beta-Antagonists↗

PubMed1989

First passage radionuclide cardiography for determination of cardiac output: evaluation of an improved method.

A noninvasive method for determination of cardiac output by aid of first passage radionuclide cardiography is presented. As opposed to most other scintigraphic methods, a forward blood flow is measured, even in patients with valvar incompetence. In addition, the technique allows measurement of cardiac output in the presence of cardiac arrhythmias. No geometrical assumptions, corrections for radiation attenuation, loss of tracer, or empirical correction factors due to extracardiac radioactivity are required. We have evaluated the method in 19 patients with various heart diseases by comparison of the radionuclide cardiac outputs with those derived from the thermodilution technique performed simultaneously. Eight patients had valvar incompetence and 2 had cardiac arrhythmias. The mean radionuclide and thermodilution cardiac output values were 5.03 l/min (SD 1.21) and 5.18 l/min (SD 1.09), respectively. The 95% confidence interval for the bias was -0.40 to 0.10 l/min, and correlation analysis demonstrated an excellent correlation between results obtained with the two methods, r = 0.91 (P less than 0.001). This study shows that the improved gamma camera method represents a valid noninvasive technique for determination of cardiac output.

Adult↗

PubMed1989

Reproducibility in the analysis of multigated radionuclide studies of left ventricular ejection fraction.

The authors determined the reproducibility (the standard deviation [SD]) in the analysis of multigated radionuclide studies of left ventricular ejection fraction (LVEF). Radionuclide studies from a consecutive series of 38 patients suspected of ischemic heart disease were analyzed independently by four nuclear medicine physiologists and four laboratory technicians. Each study was analyzed three times by each of the observers. Based on the analyses of the eight observers, the SD could be estimated by the use of a variance component model for LVEF determinations calculated as the average of the analyses of an arbitrary number of observers making an arbitrary number of analyses. This study presents the SDs for LVEF determinations based on the analyses of one to five observers making one to five analyses each. The SD of a LVEF determination decreased from 3.96% to 2.98% when an observer increased his number of analyses from one to five. A more pronounced decrease in the SD from 3.96% to 1.77% was obtained when the LVEF determinations were based on the average of a single analysis made by one to five observers. However, when dealing with the difference between LVEF determinations from two studies, the highest reproducibility was obtained if the LVEF determinations at both studies were based on the analyses made by the same observer. No significant difference was found in the reproducibility of analyses made by nuclear medicine physicians and laboratory technicians. Our study revealed that to increase the reproducibility of LVEF determinations, special efforts should be made to standardize the outlining of the end-systolic region interest.

Adult↗

PubMed1989

Plasma concentrations of adrenaline, noradrenaline and dopamine during forearm dynamic exercise.

In six healthy volunteers plasma concentrations of adrenaline, noradrenaline and dopamine were measured at rest and during dynamic forearm exercise at submaximal and maximal intensities. Arterial and venous concentrations of adrenaline and noradrenaline increased with forearm exercise at all workloads. Dopamine concentrations did not change. The increases in adrenaline and noradrenaline were almost linearly related to the increase in heart rate with no levelling off at maximal exercise intensities. It is concluded that dynamic exercise with the forearm muscle group causes a small but significant activation of the sympatho-adrenal system as reflected by increases in plasma concentrations of adrenaline and noradrenaline.

Adult↗

PubMed1989

The veteran athlete: an echocardiographic comparison of veteran cyclists, former cyclists and non-athletic subjects.

To determine the effects of prolonged endurance training on the heart, a comparison was made of veteran cyclists aged 41-51 years, former cyclists, and non-athletic subjects, including echocardiography, ECG, systolic and diastolic time intervals, and maximal oxygen uptake. The veterans had significantly larger diastolic diameter, systolic diameter, thickness of septum, posterior wall, and left ventricular mass. The enlargement of the left ventricle was found to be proportionate, as the ratio of diastolic diameter to wall thickness showed no change. In contrast to earlier reports, no indication of reduced cardiac function was found in the veterans, as echocardiographically measured function parameters, systolic, and diastolic time intervals were similar in the three groups. In the former athletes, whose previous training experience was similar to that of the veterans, no significant variation in cardiac structure and function was found in relation to the control group. This indicates that the physiological hypertrophy caused by physical training can be reversible.

Adaptation, Physiological↗

PubMed1989

Central haemodynamic changes after a meal.

Eight healthy people (seven men and one woman, aged 19 to 31 years) were studied by radionuclide cardiography when supine before and 30 minutes after a standard meal (6300 kJ). Control investigations were performed on a different day within a week of the standard meal. There was a median increase in cardiac output of 62% that was attributable to a 17% increase in heart rate and a 41% increase in stroke volume. Blood pressure and concentrations of plasma catecholamines did not change. The median end diastolic and end systolic volumes of the left ventricle increased by 41% so that the left ventricular ejection fraction was unchanged. There were no significant changes during the control experiments. In healthy people a meal caused an appreciable increase in stroke volume and dilatation of the left ventricle. The activity of the sympathetic nervous system, as measured by plasma catecholamines, did not change much, and changes in blood volume alone did not seem to explain the haemodynamic response to the meal.

Adult↗

PubMed1989

An improved noninvasive method for measurement of cardiac output and evaluation of left-sided cardiac valve incompetence.

A time-saving method was developed to label red blood cells in vitro with 99mTc while avoiding centrifugation. After tin incubation, extracellular tin was oxidized by sodium hypochlorite, and EDTA was added for stabilizing the complex prior to 99mTc incubation. Labeling yields were 95%, and in vivo decay showed a high stability with a mean biologic half-life of eleven hours. The first-passage radionuclide technique for determination of cardiac output using the above-mentioned tracer was evaluated by using the left ventricle as area-of-interest with individual background correction after complete mixing of the tracer. This technique showed a high level of agreement with invasive methods. By combining this method for measurement of the forward stroke volume with the multigated equilibrium principle for determination of the total left ventricular stroke volume using similar background corrections, an exact evaluation of regurgitation fractions was obtained. In patients with aortic and mitral valve disease the noninvasive radionuclide technique gave similar but probably more accurate results as compared with contrast aortography and ventriculography. The radionuclide technique may be suitable for monitoring and selecting patients for surgical treatment.

Aortic Valve Insufficiency↗