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Biomedical subjects

E Erdmann

Publications and source records attributed to E Erdmann.

At least 73 records · Page 4Linked to original sources
PubMed2001

Non-Q-wave myocardial infarction: impaired myocardial energy metabolism in regions with reduced 99mTc-MIBI accumulation.

Reduced regional technetium-99m methoxyisobutylisonitrile (99mTc-MIBI) accumulation in patients with chronic non-Q-wave infarction (NQWI) but without significant coronary artery stenosis indicates non-transmural damage of the myocardial wall. The aim of this study was to characterise cardiac energy metabolism after NQWI using phosphorus-31 magnetic resonance spectroscopy (31P-MRS) and to compare the biochemical remodelling with changes in regional 99mTc-MIBI uptake and with morphological and functional parameters assessed by magnetic resonance imaging (MRI). Fifteen patients with a history of NQWI, exclusion of significant coronary artery stenosis (<50% diameter stenosis) and hypokinesia of the anterior wall (group A) were examined with 31P-MRS to study the effects of NQWI on myocardial energy metabolism. Spectroscopic measurements were performed in the infarct-related myocardial region. Corresponding gradient-echo MR images and myocardial 99mTc-MIBI single-photon emission tomography images were acquired for exact localisation of the infarct region. All examinations were performed at rest under anti-ischaemic medication. Data were compared with those of patients in whom coronary artery disease had been excluded by angiography (group B, n=10). All patients of group A displayed anterior wall hypokinesia in the infarcted area on both ventriculography and MRI, with a reduced myocardial accumulation of 99mTc-MIBI (66.3%+/-11.8% vs 95.6%+/-2.2% in group B). The mean wall thickness during the complete cardiac cycle (9.5+/-1.8 mm vs 13.1+/-1.1 mm in group B, P<0.001), the systolic wall thickening (2.6+/-1.4 mm vs 5.8+/-1.5 mm in group B, P<0.01) and the phosphocreatine/adenosine triphosphate ratio (1.12+/-0.22 vs 1.74+/-0.23 in group B, P<0.01) in the hypokinetic area were all significantly reduced. It is concluded that persisting hypokinetic myocardium after NQWI combined with reduced myocellular uptake of 99mTc-MIBI displays a reduced PCr/ATP ratio. Our results indicate that morphological remodelling after NQWI is accompanied by fundamental changes in cardiac energy metabolism.

Adenosine Triphosphate↗
PubMed2001

Alcohol and the risk of myocardial infarction.

Epidemiological studies have repeatedly demonstrated a beneficial effect of moderate alcohol consumption on the incidence of coronary heart disease, myocardial infarction and overall mortality. The latter increases with excessive alcohol consumption. Although most epidemiological studies demonstrate a beneficial effect of alcohol consumption independent from the specific kind of alcoholic beverage, there is increasing evidence that wine and in particular red wine might contain pharmacological substances, which prevent atherosclerosis and myocardial infarction independent from the wine ethanol. Pathophysiological mechanisms mediating these beneficial effects include effects of wine phenols and tannins on LDL-cholesterol oxidation status, thrombocyte aggregation, endothelial function and smooth muscle cell proliferation. Identification and characterization of the pharmacologically active substances might provide the stage for the development of new substances to be used in the prevention of coronary artery disease and myocardial infarction.

Alcohol Drinking↗
PubMed2001

Results from post-hoc analyses of the CIBIS II trial: effect of bisoprolol in high-risk patient groups with chronic heart failure.

BACKGROUND: The beneficial effects of the beta-blocker bisoprolol on mortality and rate of hospitalisation as well as its safety in patients with chronic heart failure has been proven. However, its efficacy in patients in whom beta-blockers have traditionally been contraindicated or caution has been advised has not been clearly determined. Therefore, analyses in high-risk subgroups of patients taking part in CIBIS II have been performed to investigate the effect of bisoprolol in elderly patients, in patients with type 2 diabetes, with renal failure, NYHA functional class IV or concomitantly treated with digitalis, aldosterone antagonists or amiodarone. METHODS: High-risk subgroups of patients with chronic heart failure taking part in the CIBIS II study were retrospectively analysed with respect to mortality, hospitalisation, combined endpoint of cardiovascular mortality or hospitalisation for cardiovascular reasons and treatment withdrawal as well as cause of death and hospitalisation. Analysis is based on intention-to-treat. RESULTS: It was demonstrated that in spite of the expected increase in the overall risk of death and hospitalisation, patients who are diabetic, have renal impairment, NYHA class IV symptoms, are elderly, are taking either digitalis, amiodarone or aldosterone antagonists as co-medication benefit equally from beta-blockade with bisoprolol as patients without these complications or drugs. Benefit was shown for the primary endpoint all cause mortality, as well as for the secondary endpoints. CONCLUSIONS: Contrary to the hitherto prevailing doctrine of not using beta-blockers in high risk patient groups with chronic heart failure, retrospective analyses of the CIBIS II study justify the use of this drug class in patients regardless of age, NYHA functional class, the presence of diabetes, renal impairment or concomitant treatment with digitalis, amiodarone or aldosterone antagonists.

Adrenergic beta-Antagonists↗
PubMed2001

The CARE-HF study (CArdiac REsynchronisation in Heart Failure study): rationale, design and end-points.

BACKGROUND: Cardiac resynchronisation is a promising new intervention for patients with heart failure, left ventricular systolic dysfunction and ventricular dyssynchrony. OBJECTIVE: The CARE-HF trial is designed to evaluate the long-term effects of cardiac (atrio-bi-ventricular) resynchronisation on the mortality and morbidity of patients with heart failure due to left ventricular systolic dysfunction already receiving diuretics and optimal medical therapy with ACE inhibitors and beta-blockers (where indicated and tolerated). METHODS AND RESULTS: Approximately 800 patients will be randomised to device therapy or control and followed for a minimum of 18 months. A pragmatic study design has been chosen that does not attempt to conceal allocation from investigators or patients because it is impossible to guarantee maintenance of blinding for the duration of the study. The end-points committee will adjudicate events in a blinded fashion. Since cardiac resynchronisation may alter other aspects of the management of the patient, as would occur in clinical practice, the study should be considered a comparison of strategies rather than simply of a device. The primary end-point is all-cause mortality or unplanned cardiovascular hospitalisation. The study should complete recruitment during 2002 and report in 2004.

Adrenergic beta-Antagonists↗
PubMed2001

Na+ channel activators as positive inotropic agents for the treatment of chronic heart failure.

The Na+ channel agonists DPI 201-106, BDF 9148 and BDF 9198 are a new group of positive inotropic agents which increase cardiac contractility in a cAMP independent manner. The most likely mechanism by which positive inotropy is mediated is an enhancement of Na+/Ca2+ exchange activity in response to a Na+ channel agonist induced increase in the cardiac myocyte intracellular Na+ concentration. While the positive inotropic effect of drugs which exert their effects in a cAMP dependent manner is blunted in failing compared to nonfailing myocardium, the efficacy and potency of Na+ channel agonists is not only maintained, but enhanced in failing myocardium. This finding makes these substances interesting for the treatment of patients with heart failure. The positive inotropic effects of the Na+ channel agonists, however, are accompanied by a potential increase in the incidence of cardiac arrhythmias. These side effects might limit the clinical use of Na+ channel agonists and demand future development of Na+ channel modulators without significant arrhythmogenic effects.

Animals↗
PubMed2001

Identification of hemodynamically significant restenosis after percutaneous transluminal coronary angioplasty in acute myocardial infarction by transesophageal dobutamine stress echocardiography and comparison with myocardial single photon emission computed tomography.

BACKGROUND: Beside thrombolysis, percutaneous transluminal coronary angioplasty (PTCA) has become a well-established treatment for acute myocardial infarction. However, restenosis occurs in approximately 15%-40% of patients. Despite a frequently occurring infarct-related regional systolic dysfunction at rest, the identification of hemodynamically relevant restenosis seems important in terms of risk stratification, adequate treatment, and possible improvement of prognosis in these patients. This study was designed to assess the role of transesophageal dobutamine stress echocardiography and myocardial scintigraphy for identification of hemodynamically significant restenosis after PTCA for acute myocardial infarction. METHODS: Multiplane transesophageal stress echocardiography (dobutamine 5, 10, 20, 30, and 40 micrograms/kg per min) studies and myocardial single photon emission computed tomography (SPECT) studies were performed in 40 patients, all of whom underwent PTCA in the setting of acute myocardial infarction > or = 4 months prior to the test. Repeated coronary angiography was performed in all study patients who showed stress-induced perfusion defects or wall-motion abnormalities, or both. RESULTS: Significant restenosis (> or = 50%) was angiographically found in 15 (37.5%) of 40 patients. Of these 15 patients, transesophageal dobutamine stress echocardiography identified restenosis in 12 (80%) and myocardial SPECT in 14 (93%), yielding diagnostic agreement in 70% of patients. Echocardiographic detection of restenosis was based mainly on a biphasic response to increasing doses of dobutamine. Sensitivity and specificity for identification of hemodynamically relevant restenosis in individual patients was 80% and 92%, respectively for dobutamine stress echocardiography versus 93% and 68% for myocardial SPECT. CONCLUSIONS: Both transesophageal dobutamine stress echocardiography and myocardial SPECT were highly sensitive in identifying significant restenosis after PTCA for acute myocardial infarction. Therefore, either test, as a single diagnostic tool or especially if performed together, are clinically valuable alternatives to coronary angiography for the detection of restenosis after PTCA for acute myocardial infarction.

Acute Disease↗
PubMed2001

[Comparison of dobutamine-stress magnetic resonance imaging and dipyridamole-TL-201-SPECT as alternative strategies for the detection of coronary artery dis in patients no suitable for stress echocardiography].

AIM: During the past decade stress-echocardiography has gained increasing popularity for detection of myocardial ischemia in patients with coronary artery disease. However, about 10% to 15% of the patients submitted for stress-echocardiography do not have an adequate acoustic window. The purpose of this study was to compare high-dose dobutamine-stress magnetic resonance imaging (dobutamine-MRI) with dipyridamole-Tl-201-SPECT (dipyridamole-SPECT) as alternative strategies for detection of myocardial ischemia in patients with inadequate image quality by stress-echocardiography. PATIENTS AND METHODS: Of 296 patients which were consecutively submitted to stress-echocardiography 45 patients (15%) had two or more segments that could not be evaluated according to the 16-segment-model of the American Society of Echocardiography. They underwent dobutamine-MRI and dipyridamole-SPECT studies, which were evaluated using a 28-segment modell. Myocardial segments were attributed to perfusion territories of the coronary arteries. The results of ischemia detection were compared to the results of coronary angiography (stenosis > or = 50%). RESULTS: In comparison to coronary angiography dobutamine-MRI yielded a sensitivity of 87%, a specificity of 86%, a positive predictive value of 93%, a negative predictive value of 75% and a diagnostic accuracy of 86%. For dipyridamole-SPECT results were 90%, 86%, 93%, 80% and 89%, respectively. These values were not significantly different. CONCLUSIONS: In patients not suitable for stress-echocardiography, both dobutamine-MRI and dipyridamole-SPECT are reliable strategies for detection of myocardial ischemia. Selection is dependent on the patient criteria, technical considerations, local logistics and experience of the observer.

Adrenergic beta-Agonists↗
PubMed2000

[Dobutamine-induced changes in the myocardial blood flow in patients with coronary heart diseases. A quantitative analysis using [15O] H2O positron emission tomography].

BACKGROUND AND OBJECTIVE: Although dobutamine is currently widely used for stress testing, only little is known about the effects of dobutamine on myocardial blood flow. The purpose of the present study was therefore to analyze quantitatively the regional changes in myocardial blood flow during rest and stress. PATIENTS AND METHODS: In order to assess these effects 17 patients (12 men, five women, mean age 57 +/- 8 years) with symptomatic single vessel coronary artery disease (> 70% stenosis) scheduled for coronary angioplasty underwent dobutamine stress testing with a maximum dose of 40 micrograms/kg/min. Myocardial blood flow was measured using 15O H2O position emission tomography at rest and during maximum stress in ischemic and non-ischemic myocardial regions. RESULTS: Dobutamine stress (median dose 30 micrograms/kg/min) increased the rate pressure product significantly (from rest 8697 [95% confidence interval 7959-9435] to stress 16,512 [15,208-17,815] mmHg/min (p < 0.001). Myocardial blood flow during rest was similar in non-ischaemic and ischaemic regions (0.91 [0.93; 0.83-1.28] vs. 1.10 [1.23; 0.91-1.28] ml/min/g, n.s.). During dobutamine stress myocardial blood flow increased in non-ischaemic regions to 2.17 (2.15; 1.77-2.57) ml/min/g, while myocardial blood flow did not increase in ischaemic regions (1.06 [0.97; 0.83-1.28], p < 0.001). Accordingly, dobutamine coronary reserve was 2.42 (2.55; 2.10-2.74) for non-ischaemic regions and 0.98 (1.05; 0.84-1.13) for ischemic regions (p < 0.001). Rate pressure product and myocardial blood flow were significantly correlated (r = 0.79, p < 0.001). CONCLUSION: A dobutamine-induced increase in rate pressure product was proportional to an increase in myocardial blood flow in non-ischaemic regions. In contrast, myocardial blood flow did not increase in myocardial regions supplied by a severely stenosed coronary artery.

Blood Flow Velocity↗
PubMed2000

Magnetic resonance pharmacological stress for detecting coronary disease. Comparison with echocardiography.

Stress testing is the cornerstone in the diagnosis of patients with suspected coronary artery disease (CAD). Although exercise ECG remains the primary approach for the detection of ischemia in patients with chest pain syndromes, its sensitivity and specificity is limited and exercise ECG does not provide detailed information about the localisation and extent of CAD. Stress echocardiography has been used for the detection of ischemia for more than a decade and has become an increasingly popular noninvasive method for the detection of CAD. In experienced hands wall motion analysis based on stress echocardiography has proved to be as sensitive and specific for the detection of myocardial ischemia as scintigraphic techniques. Recent technical improvements, namely the availability of ultrafast imaging sequences with a significant reduction of imaging time have initiated several studies which examined the combination of pharmacological stress and magnetic resonance imaging (MRI) for the detection of suspected CAD. The most well developed stress-MRI technique is wall motion imaging during dobutamine stress. This technique is analogous to stress echocardiography, but MRI has the inherent advantages of better resolution, higher reproducibility and true long and short axis imaging with contiguous parallel slices. However, the clinical impact of MRI for the diagnosis of CAD is still low. Further technical developments including real time imaging and a reliable automated quantitative analysis of left ventricular function are required before stress-MRI becomes a serious challenge to stress-echocardiography in the clinical arena. Currently, only a few MRI facilities and physicians are dedicated to pharmacological stress testing with MRI and the future clinical impact of this promising technique will depend on its potential to provide information beyond myocardial function including perfusion, metabolism and coronary anatomy in form of a "one-stop"-shop for the cardiac patient.

Cardiotonic Agents↗