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Biomedical subjects

U Staedt

Publications and source records attributed to U Staedt.

At least 19 recordsLinked to original sources
PubMed2002

[Differential thoracic pain diagnosis. An internal medicine challenge].

In the event of chest pain developing, the task of initial evaluation must be either to confirm and treat an acute life-threatening condition, or to exclude it. The diagnosis of a harmless functional disorder can be established only after the exclusion of a number of cardiovascular, pulmonary or gastrointestinal conditions, as also infection or malignancy. Such an approach often requires cooperation with orthopedic surgeons, general surgeons, psychiatrists and also pain specialists.

Cardiovascular Diseases↗
PubMed2002

[Rapid assessment of thoracic pain. Is it a myocardial infarct?].

The high mortality rate of acute myocardial infarction underline the importance of this entity in the differential diagnosis of acute chest pain. Medical history, clinical presentation, ECG, biochemical markers of myocardial injury and imaging techniques are used to establish a correct diagnosis. Myocardial infarction can be divided into ST-segment elevation myocardial infarction and non-ST-segment elevation myocardial infarction. In the case of ST-segment elevation myocardial infarction thrombolytic therapy or percutaneous transluminal coronary angioplasty should be instituted as soon as possible. In patients without persistent ST-segment elevation biochemical markers of myocardial damage, especially troponin T and troponin I, are of major importance for risk stratification. Patients with elevated troponin levels should be treated with GPIIb/IIIa antagonists and early intervention.

Chest Pain↗
PubMed2000

Efficacy of single lead VDD pacing in patients with impaired and normal left ventricular function.

Atrial synchronous ventricular pacing seems to be the best pacing mode for patients with advanced AV block and impaired LV function. The long-term follow-up of single lead VDD pacing was studied in 33 patients with impaired LV function and compared to 42 patients with normal LV function. All patients received the same VDD lead and VDDR pacemaker. The lead model with 13-cm AV spacing between the atrial and ventricular electrode was implanted in 89% of the patients. Follow-ups were 1, 3, 6, and 12 months after implantation. The percentage of atrial sensing and the P wave amplitude were determined at each follow-up. Minimal P wave amplitude at implantation was 2.0 +/- 1.4 mV in patients with impaired and 1.7 +/- 0.9 mV with normal LV function (not significant). At the 12-month follow-up, 33 patients with normal and 23 patients with depressed LV function remained paced in the VDD mode. The remaining patients died in five (impaired LV function) and seven cases (normal LV function) or their pacemakers were programmed to the VVI/VVIR pacing mode in four (impaired LV function) and three cases (normal LV function). P wave amplitude did not differ in the two groups (e.g., at month 12: impaired: 1.17 +/- 0.42 mV; normal: 1.09 +/- 0.49 mV). The atrial sensitivity was programmed in most patients to sensitive settings with no differences between the two groups (e.g., at month 12: impaired: 0.13 +/- 0.06 mV; normal: 0.13 +/- 0.05 mV). The diagnostic counters indicated nearly permanent atrial sensing (e.g., at month 12: impaired: 99.3 +/- 2.2%; normal: 99.0 +/- 1.0 mV). In conclusions, single lead VDD pacing restored AV synchronous ventricular pacing in patients with normal and with impaired LV function indicating that it could be an alternative to DDD pacemakers, but not to dual-chamber pacing.

Aged↗
PubMed1998

[The intraoperative measured stimulation impedance of pacemaker electrodes is not a predictor for their longevity].

UNLABELLED: As pacing impedance is inversely related to pacing current, the increase of pacing impedance additionally decreases pacing current. Whether the impedance measurement at implantation predicts the outcome during follow-up, was studied in 87 patients who received the VDD-single lead UniPass 425 connected to the pacemaker Unity (Sulzer Intermedics). The impedance changes between implantation and 6 months follow-up were assessed for each patient. Similar impedance values were defined, if the two measurements were within a range < or = -100 to +100 omega. Six-months impedance was lower or higher compared to implantation, if the difference exceeded > -100 or > +100 omega. At implantation, impedance was 535 +/- 98 omega (range: 333-811 omega) and significantly increased to 604 +/- 160 omega (range: 361-1150 omega) after 6 months. Mean difference between the two measurements was 69 +/- 162 omega (range: -336 bis + 560 omega). Similar impedance had 43 (implantation: 527 +/- 75 omega, 6 months: 531 +/- 87 omega), lower values 11 (implantation: 660 +/- 83 omega, 6 months: 494 +/- 73 omega) and higher values 33 patients (implantation: 503 +/- 99 omega, 6 months: 735 +/- 168 omega). Compared to the patients with similar impedance patients with lower impedance had a significantly higher impedance values at implantation. CONCLUSIONS: Pacing impedance increased significantly within 6 months after implantation. Pacing impedance changed > 100 omega in 51% of the patients. The long-term follow-up of pacing impedance can be predicted generally, but not for the individual patient.

Aged↗
PubMed1997

[The effect of a lower stimulation frequency on the AV synchronicity of VDD pacemakers].

BACKGROUND AND OBJECTIVE: Implantation of a VDD pacemaker (ventricular pacing; dual sensing [atrial and ventricular]; dual response [triggered + inhibited]) together with a single VDD electrode catheter restores synchronous AV ventricular stimulation in patients with higher-grade AV block and intact sinus function. If higher-frequency stimulation occurs it may be a sign of pacemaker malfunction or of inadequate pacemaker programming. This study was undertaken to determine, at first follow-up examination, in how many patients with a VDD pacemaker VVI stimulation occurred more than 5% of the time; how such patients differed from those with 5% or fewer VVI stimulations; and whether a changed program reduced the proportion of VVI stimulations. PATIENTS AND METHODS: 67 consecutive patients were tested 1 to 3 months after implantation of the Unity VDD pacemaker (Sulzer Intermedics). The frequency of VVI stimulations was determined via a diagnostic pacemaker memory store. After intermediate analysis, programming was optimized and the patients then re-tested 12 months after the initial implantation. RESULTS: At the first follow-up examination 54 patients had VVI stimulations of < or = 5% (0.5 +/- 0.9%) and 13 had > 5% of the time (19.8 +/- 10.7%). The two groups differed significantly from one another in their lower intervention frequency (< or = 5% VVI stimulations: 47 +/- 6/min; > 5% VVI stimulations: 58 +/- 5/min). In particular, the pacemakers in patients with > 5% VVI stimulations had been significantly more often programmed to values of > 50/min. As a result, the pacemakers of these patients were reprogrammed to a lower frequency. A year after implantation there was no longer any difference in the lower intervention frequency, 44 +/- 4/min, between patients with initially > 5% VVI stimulations and those with initially < or = 5% stimulations. At the same time, the proportion of VVI stimulations fell to 4 +/- 6%, with 67% of patients having AV synchronicity of > 95%. INTERPRETATION: At first follow-up, patients with > 5% VVI stimulations differed from those with < or = 5% stimulations with regard to an increased lower intervention frequency. In most of these patients the proportion of AV stimulations was increased to > 95% by reducing the lower intervention frequency to < or = 50/min.

Aged↗
PubMed1997

Evaluation of signal-averaged cardiokymography for the detection of ischaemic left ventricular dysfunction.

UNLABELLED: Cardiokymography (CKG) is a non-invasive method for the detection of patients with coronary artery disease (CAD). Issues of the present study were to evaluate the feasibility, sensitivity and specificity of a recently developed signal-averaged CKG system for detecting patients with pharmacologically induced ischaemic left ventricular wall motion abnormalities (WMA) during pharmacologic stress echocardiography (SE). Precordial CKG curves were recorded in 100 consecutive patients who underwent dobutamine-SE for suspected CAD. For interpretation, CKG curves were classified into three different types, depending on the degree of systolic outward motion. CKG test results were regarded as positive (indicating myocardial ischaemia) if there was a change of the baseline CKG type at peak pharmacologic stress. The CKG test results were positive in 18 of 27 patients with a pathologic dobutamine-SE (sensitivity 67%), but did not show any change of the prior CKG type in 57 of 69 patients with a normal SE (specificity 83%). Patients with a true positive CKG test had significantly (P<0.05) more echocardiographic segments with WMA than patients with a false negative CKG test. CONCLUSIONS: Signal-averaged CKG can detect patients with ischaemic ventricular dysfunction. Sensitivity of CKG in detecting patients with WMA depends on the extent of left ventricular ischaemia. Further studies are needed to define the diagnostic value of signal-averaged CKG in the non-invasive detection of patients with suspected CAD.

Adult↗
PubMed1997

Detection of patients with restenosis after PTCA by dipyridamole-atropine-stress-echocardiography.

Stress-echocardiography (SE) has been proven to be a valuable method for the diagnosis of coronary artery disease. For patients who cannot exercise, pharmacological stress-echocardiography represents an alternative method for the induction of cardiovascular stress. Few studies exist concerning the value of dipyridamole-SE for the detection of restenosis in patients after primary successful PTCA. It has been demonstrated that the addition of atropine can significantly increase the diagnostic potential of dipyridamole-SE, especially in patients with 1- or 2-vessel disease. The purpose of our study was to investigate the diagnostic value of high-dose dipyridamole-SE plus atropine (DASE) for the detection of restenosis after primary successful PTCA. We investigated 65 patients 3-6 months after PTCA before a control angiography was performed. Restenosis was defined as > 70% lumen narrowing, determined by quantitative coronary angiography. In 20/27 patients with restenosis, the DASE was pathological (sensitivity 74%); in 34/38 patients without restenosis the DASE was normal or showed no induced WMA (specificity 89%). Patients with tight restenosis (> 90%) were always correctly detected by DASE. Concerning the different vessels, restenosis of the LAD was correctly predicted by DASE in 11/12 patients, restenosis of the LCX in 6/9 patients and restenosis of the RCA in 8/11 patients. From the results of our study we conclude that DASE is a reliable diagnostic method for the non-invasive evaluation of patients after PTCA. DASE can identify patients with relevant restenosis after PTCA and help to select those patients who will probably benefit from further coronary interventions, for repeat angiography.

Angioplasty, Balloon, Coronary↗
PubMed1997

Continuous measurement of hemodynamic alterations during pharmacologic cardiovascular stress using automated impedance cardiography.

The contribution of computerized impedance cardiography in monitoring and differentiating cardiovascular responses to pharmacologic stress after the administration of dipyridamole (group 1, n = 24) or dobutamine (group 2, n = 26) was investigated during stress echocardiography. Heart rate, stroke volume index, cardiac index and systemic vascular resistance index were evaluated continuously with an automated, computerized, signal-averaged impedance cardiography system. Dipyridamole had little average effect on heart rate, stroke volume index, and cardiac index. The responses were similar in patients with positive (n = 9) or negative (n = 15) stress echocardiography test results (as characterized by echocardiographic wall-motion abnormalities). Dobutamine induced a similar mean increase in heart rate in patients with negative (n = 13) or positive (n = 13) results on stress echocardiography. The mean increase in stroke volume index induced by dobutamine was greater in patients with negative stress echocardiography test results than in patients with stress-induced wall-motion abnormalities. This distinction was also seen in the cardiac index; the mean change in patients with negative stress echocardiography test results was larger than in patients with positive results. It is concluded that automated computerized impedance cardiography not only allows surveying and monitoring hemodynamic changes during pharmacologic stress echocardiography but also contributes to differentiation of pathologic stress responses.

Adult↗
PubMed1996

Hyperammonemia-induced depletion of glutamate and branched-chain amino acids in muscle and plasma.

BACKGROUND/AIMS: Exogenous hyperammonemia is known to decrease the plasma levels of branched-chain amino acids (BCAA). To investigate whether changes in intracellular amino acid concentrations of muscle are associated with and may, at least in part, mediate this effect, experiments were carried out on a total of 60 male Wistar rats. METHODS: Five groups were formed in a randomized manner. Group A: no treatment; groups B1 and B2: 2-hour and 6-hour continuous central-venous infusions, respectively, of sodium salts; groups C1 and C2: 2-hour and 6-hour infusions of ammonium salts. We obtained venous blood samples and muscle biopsies. Plasma ammonia, whole blood glucose, serum insulin, blood pH, and amino acids in plasma as well as in the intracellular water of muscle were measured. RESULTS: As compared with control group A, groups C1 and C2 displayed a 3.3- and a 4-fold increase, respectively, in the plasma ammonium concentration. Regarding insulin, the ammonium-infused rats were similar to group A but not to the sodium-infused B groups, which had significantly lower insulin concentrations. Administering ammonium brought about a decline in BCAA concentrations in plasma after 2 hours and in muscle after 6 hours. The ammonium-induced fall in intracellular BCAA values was preceded by an increase of glutamine as well as by a decrease of glutamate and alanine in both plasma and muscle. CONCLUSIONS: It is pointed out that the inter-group differences in serum insulin, although possibly accounting for some of the findings, can by no means explain the entire pattern of amino acid concentrations seen after the ammonium infusions. Instead, our results agree with the hypothesis that hyperammonemia indirectly lowers the plasma levels of BCAA by stimulating glutamine synthesis, thus reducing the intracellular glutamate pool, which is likely to be restored, at least in part, by an intensified BCAA transamination. Clarification is needed as to whether carbon skeletons derived from valine and isoleucine additionally contribute to replenishing the glutamate pool.

Alanine↗
PubMed1996

[Value of dipyridamole-atropine stress echocardiography for detection of patients with restenosis after PTCA].

UNLABELLED: Stress-Echocardiography has been proven to be a valuable method in the diagnosis of patients with suspected coronary artery disease. It has been demonstrated that the addition of atropine can increase the sensitivity of pharmacological stress-echocardiography-tests. The aim of our study was to evaluate the diagnostic potential of dipyridamole-atropine-echocardiography for the detection of restenosis after coronary angioplasty. We investigated 50 patients 3-6 months after primary successful coronary angioplasty. Restenosis was defined as recurrence of stenosis of > or = 70% at the site of dilatation determined by quantitative coronary angiography. All patients were investigated on antianginal medication and underwent control-coronary angiography within 1-3 days after the echocardiographic study. In 17/23 patients with restenosis, the dipyridamole-atropine-stress-test was pathologic (sensitivity 74%), in 25/27 patients without significant restenosis the echocardiography stress-test was normal (specificity 93%). In 6 patients with restenosis and an unsuspicious stress-test, the percent diameter of restenosis did not exceed > or = 90% lumen narrowing, restenosis of the LAD was correctly identified in all patients (n = 11). The diagnostic accuracy of the dipyridamole-atropine-stress-test for the detection of patients with restenosis after PTCA in our study was 84%, the positive predictive value of a pathologic echocardiography stress-test for the detection of significant restenosis was 89%, the negative predictive value was 81%. CONCLUSIONS: Dipyridamole-atropine-echocardiography has diagnostic potential for non-invasive assessment of patients after coronary angioplasty. In patients with a normal echocardiographic stress-test, the probability of significant restenosis is considerably low, even if restenosis cannot be definitely excluded.

Aged↗
PubMed1995

Substrate balances across colonic carcinomas in humans.

To investigate the utilization of nutrients by malignant tumors in humans, the balances of energy-yielding substrates and amino acids across colonic carcinomas were assessed in 17 patients during surgery. Blood samples were taken from an artery and the main tumor-draining vein, which was also used for determining tumor blood flow (direct venous outflow technique). Additionally, the substrate exchange by peripheral tissues was studied (femoral arteriovenous differences, venous occlusion plethysmography). Mean blood flow was greater in the carcinomas than in the leg tissues (43.2 versus 2.5 ml/100 ml/min; P < 0.001). There was a negative correlation between tumor blood flow and tumor weight (r = -0.87; P < 0.001). Glucose net uptake and lactate release by the malignancies exceeded the peripheral exchange rates 30- and 43-fold, respectively (mean values different at P < 0.001). The molar ratio of lactate output to glucose consumption was 0.78 in the tumors and 0.48 in the leg tissues (P < 0.05). Regarding free fatty acid and ketone body balances, no significant tumor-periphery differences were noted. The carcinomas utilized branched chain amino acids and serine, while alanine and, in particular, ammonia were released in large amounts. Net glutamine retention was not consistently observed. It is concluded that the energy metabolism of human colonic carcinomas relies predominantly on glucose, with fat-derived calories making no appreciable contribution. The impaired nutritive perfusion of malignant tumors appears to favor glycolysis and to limit both glucose oxidation and glutaminolysis. The present study has shown that the procedure chosen for the assessment of trans-tumor substrate flux rates is a workable and valid model for analyzing metabolic balances across human colonic cancers in vivo.

Adult↗
PubMed1994

[Nightly myoclonus syndrome (NMS) and restless legs syndrome (RLS)--review and case report].

The paper gives a brief review of the existing literature concerning the nocturnal myoclonus syndrome (NMS). The clinical symptomatology, criteria for differential diagnosis and the relation to the restless legs syndrome (RLS) are discussed. Recently we investigated central dopamine receptor density with 123I-labeled 3'-iodo-6-methoxybenzamide (IBZM) (a highly selective CNS D2 dopamine receptor ligand) and single photon emission tomography (SPECT) in patients with NMS and found a reduced density of dopamine D2-receptors in the striatal structures, indicating a dopaminergic dysfunction in NMS and RLS. We present a report concerning a 58-year old female with NMS-associated insomnia and present IBZM SPECTs and hypnograms before and after a 3-month treatment with L-dopa and discuss the results with regard to pathophysiological theories.

Epilepsies, Myoclonic↗
PubMed1993

Effects of ornithine aspartate on plasma ammonia and plasma amino acids in patients with cirrhosis. A double-blind, randomized study using a four-fold crossover design.

This paper documents dose-dependent effects of ornithine aspartate (OA) on postprandial hyperammonemia and plasma amino acids. Ten patients with cirrhosis were randomized to undergo 1 out of 4 infusion series. Each series consisted of four 8-h infusions (09:00 h-17:00 h), with placebo (NaCl), 5 g, 20 g or 40 g of OA being administered on separate days in varying sequences. This 4-fold crossover design was double-blind. On infusion days, patients received 2 oral protein loads (0.25 g/kg at 09:00 h and 0.5 g/kg at 13:00 h). Venous blood samples were drawn every 2 h and the 24-h urine was collected. In addition to measuring plasma ammonia and amino acids, the urea production rate, serum glucose and serum insulin were analyzed. A significant postprandial rise in the ammonia concentration was noted during the infusions of placebo and 5 g of OA but did not occur with the dosages of 20 g (after the second protein load) and 40 g (after both protein loads). Furthermore, the latter dose, compared with placebo, significantly reduced plasma ammonia after the minor protein load. Urea production rate increased when 20 g or 40 g of OA was administered. Of the amino acids involved in the metabolic pathways of ornithine and/or aspartate, glutamate showed a rise in its plasma level following infusion of 40 g of OA, whereas glutamine did not. Concentrations of methionine, phenylalanine, tyrosine, threonine, serine and glycine declined progressively with increasing doses of OA (5-40 g). The highest dose of the drug caused hyperglycemia and hyperinsulinemia.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Haemodilution in acute ischaemic stroke comparison of two haemodilution regimen.

In a prospective study we randomly allocated 50 patients with acute ischaemic stroke in the area of the middle cerebral artery within 12 hours after onset to two moderate hypervolemic haemodilution regimen consisting of 500 ml of 10% hydroxyethyl starch per day for 10 days. In the high haematocrit group the target haematocrit of 41-42% was achieved by 0-3 phlebotomies and additional replacement of that volume with the colloid in 3 days. In the low haematocrit group with 1-4 phlebotomies a target haematocrit of 37-38% was reached in 4 days. The groups did not differ regarding age, risk factors, haematocrit and neurological score. The improvement of the disturbed blood rheology was more pronounced in the low haematocrit group. One death occurred in each group. The neurological score showed a significantly greater increase in the low haematocrit group with +59% at day 5 and +125% at day 11; the data for the high haematocrit group were +34% and +89% respectively. We calculated a correlation (r = 0.36, p less than 0.02) between the rise in neurological score and the reduction of haematocrit. Our data suggest but not do prove that an early start on moderate hypervolemic haemodilution is beneficial in patients with acute ischaemic stroke and disturbed blood rheology.

Aged↗