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Biomedical subjects

H Sochor

Publications and source records attributed to H Sochor.

At least 37 records · Page 2Linked to original sources
PubMed1994

Automated interpretation of planar thallium-201-dipyridamole stress-redistribution scintigrams using artificial neural networks.

UNLABELLED: To develop an automated image interpretation system of planar cardiac 201Tl dipyridamole stress/redistribution scintigrams, the authors used artificial neural networks that associate patterns of segmental myocardial thallium uptake with a diagnostic assessment about the presence, severity and localization of significant coronary artery disease. METHODS: Artificial neural networks were trained and evaluated using the results from segmental thallium analysis and either expert readings in 159 cases or coronary angiography in a subgroup of 81 patients. RESULTS: Based on receiver operating characteristics analysis, the sensitivity for the detection of significant coronary artery disease at a specificity of 90% was 51% compared with angiography and 72% compared with the human expert. For severity and localization of disease, two vascular territories assigned to the vascular bed of the left anterior descending (LAD) artery and to the territory subtended by the left circumflex artery and the right coronary artery together (CX/RCA) were included in the analysis. CONCLUSION: Artificial neural networks may be useful to develop automated computer-based image interpretation systems of 201Tl perfusion scintigrams. However, utilization of large training datasets appears to be a prerequisite to achieve adequate diagnostic performance.

Adult↗
PubMed1993

Indium 111-monoclonal antimyosin antibody and magnetic resonance imaging in the diagnosis of acute Lyme myopericarditis.

BACKGROUND: Lyme borreliosis is a tick-borne multisystem disorder that may present as self-limiting early or persistent chronic diseases of the skin, nervous system, joints, heart, and other organs. Cardiac involvement has mainly been reported as acute atrioventricular conduction disturbances or transient ventricular dysfunction. METHODS AND RESULTS: We treated a patient with clinical signs of acute myopericarditis and serologic evidence of Lyme borreliosis confirmed by silver staining of endomyocardial biopsy specimens and indium 111-monoclonal antimyosin antibody scan, which we believe has not been reported previously. Additionally, magnetic resonance imaging revealed epicardial and myocardial areas of increased intensity. CONCLUSION: Indium 111-monoclonal antimyosin antibody scanning and magnetic resonance imaging might play an additional important role in assessing and confirming the diagnosis of Lyme carditis in the presence of clinical symptoms and positive serologic findings.

Acute Disease↗
PubMed1992

Cardiac involvement in systemic sclerosis.

OBJECTIVE: To assess the incidence and extent of cardiac involvement in systemic sclerosis (SSc) patients with no apparent cardiac symptoms. METHODS: Surface electrocardiography, ambulatory electrocardiography, radionuclide ventriculography, myocardial scintigraphy, and echocardiography were performed in 18 patients. RESULTS: These studies demonstrated ventricular tachycardia in 1 patient, nonsustained ventricular tachycardia in 5, supraventricular tachycardia in 6, decreased left ventricular ejection fraction in 2, decreased right ventricular ejection fraction in 8, and stress-induced reversible myocardial perfusion abnormalities in 6. CONCLUSION: These observations demonstrate a high rate of cardiac abnormalities in SSc patients without cardiac symptoms.

Aged↗
PubMed1992

[Pimobendan (UDCG 115 BS) in long-term therapy of chronic heart failure].

Pimobendan is a positive inotropic agent with additional calcium-sensitizing effects of the phosphodiesterase III-inhibitor group. In short-term studies, beneficial hemodynamic effects have been demonstrated in patients with congestive heart failure. The aim of this prospective study was to examine the long-term effect of pimobendan (during at least 6 months) on subjective state, hemodynamic parameters, and arrhythmias in patients with congestive heart failure NYHA classes II and III. After double-blind randomization, 24 patients received pimobendan 5 mg bid or placebo orally in addition to a basic therapy (diuretics, digitalis). After 3 months, pimobendan-treated patients showed a significant clinical improvement (p < 0.03). In the placebo group, one patient underwent acute cardiac transplantation due to rapid clinical deterioration; another patient died suddenly after 5 months. No cardiac events occurred in the pimobendan group. In comparison to placebo, no proarrhythmogenic effect of pimobendan was detected. Clinical stabilization of patients in the pimobendan group was not paralleled by improvement of the hemodynamic parameters of left-ventricular performance.

Cardiac Volume↗
PubMed1991

Platelet survival in patients with dilated cardiomyopathy.

Dilated cardiomyopathy is associated with thromboembolic complications, which correlate poorly, however, with a visible left ventricular thrombus. Therefore, this study was performed to assess whether an abnormality of platelet function in vivo can be detected in patients with dilated cardiomyopathy. Platelet survival was measured after autologous labeling with indium-111 oxine in 28 patients with dilated cardiomyopathy and angiographically normal coronary arteries (mean ejection fraction 21 +/- 9% [standard deviation], range 4 to 39%) and in nine patients with coronary artery disease and similar left ventricular dysfunction (mean ejection fraction 21 +/- 10%). Plasma levels of beta-thromboglobulin and platelet factor 4 were measured in patients with idiopathic cardiomyopathy (n = 15) and platelet scintigraphic images of the heart (n = 24) were obtained in subsets of both patient groups. Platelet survival was significantly and similarly shortened in patients with idiopathic and ischemic cardiomyopathy (67 +/- 34 and 55 +/- 24 h, respectively) compared to controls (209 +/- 9 h, n = 12; p less than 0.001). Of the two platelet-specific proteins, beta-thromboglobulin was increased in the patients compared with controls (42 +/- 17 versus 22 +/- 6 ng/ml, p less than 0.001). Platelet scintigraphy 24 h (n = 24) and/or 48 h (n = 9) after labeling showed a diffuse pattern of enhanced platelet uptake over the heart which varied in intensity among patients, but which was never seen in controls (n = 6). This increased platelet uptake was similar in patients with idiopathic and ischemic cardiomyopathy but did not correlate with either ejection fraction or cardiothoracic ratio.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

[Diagnosis of arrhythmogenic right ventricular disease using magnetic resonance tomography].

In our study, 12 patients with ventricular arrhythmias, but without any documented cardiac disease, and 10 healthy volunteers were investigated by spin echo magnetic resonance tomography (MRT) using a 0.5 Tesla magnet. Axial T1-weighted spin-echo sequences, as well as double angulated, multislice-multiphase sequences were acquired. Left- and right-ventricular volumes were then evaluated by outlining the endocardium in an end-systolic and an end-diastolic frame. The right-ventricular free wall and the right-ventricular outflow tract were investigated for myocardial thickness and intramural fat.

Adipose Tissue↗
PubMed1991

Transient myocardial perfusion abnormalities during cold provocation test in patients with arterial hyperreactivity.

The effect of peripheral cold provocation on myocardial perfusion was evaluated utilizing thallium-201 perfusion imaging in 13 selected patients with arterial hyperreactivity (Raynaud's phenomenon: n = 8; migraine: n = 6) and angiographically documented coronary artery spasm. Eleven out of 13 subjects with coronary arterial spasm--but none of a group of patients with obstructive coronary artery disease--had transient myocardial perfusion defects during cold provocation. The localization of transient perfusion abnormalities during myocardial scintigraphy correlated with the myocardial areas distal to the spontaneous or ergonovine-induced coronary arterial spasm detected by angiography. Transient reduction of tracer uptake during cold provocation and normalization of myocardial perfusion by redistribution imaging was paralleled by areas of hypokinesia observed during the test by contrast ventriculography (n = 8). The described findings in the coronary system during peripheral cold pressor test occurred independently of the presence of Raynaud's phenomenon, and without achieving the ischemic threshold.

Adult↗
PubMed1990

Technetium-99m sestamibi in chronic coronary artery disease: the European experience.

Since the introduction of technetium-99m methoxy-isobutyl isonitrile (Tc-99m sestamibi) in Europe, there has been a growing interest in its use. Several European multicenter trials have been conducted to evaluate this new agent in relation to the traditional perfusion marker thallium-201, and other studies are in progress to understand the use of this perfusion marker for the diagnosis of coronary disease, for use in conjunction with pharmacologic vasodilation, for use in the assessment of ventricular function and wall motion and for the assessment of interventions.

Coronary Disease↗
PubMed1989

Sustained nonoxidative glucose utilization and depletion of glycogen in reperfused canine myocardium.

Ischemically injured reperfused myocardium is characterized by increased 18F-fluorodeoxyglucose uptake as demonstrated by positron emission tomography. To elucidate the metabolic fate of exogenous glucose entering reperfused myocardium, D-[6-14C] glucose and L-[U-13C] lactate were used to determine glucose uptake, glucose oxidation and the contribution of exogenous glucose to lactate production. The pathologic model under investigation consisted of a 3 h balloon occlusion of the left anterior descending coronary artery followed by 24 h of reperfusion in canine myocardium. The extent and severity of myocardial injury after the ischemia and reperfusion were assessed by histochemical evaluation (triphenyltetrazolium chloride and periodic acid-Schiff stains). Thirteen intervention and four control dogs were studied. The glucose uptake in the occluded/reperfused area was significantly enhanced compared with that in control dogs (0.40 +/- 0.14 versus 0.15 +/- 0.10 mumol/ml, respectively). In addition, a significantly greater portion of the glucose extracted immediately entered glycolysis in the intervention group (75%) than in the control dogs (33%). The activity of the nonoxidative glycolytic pathway was markedly increased in the ischemically injured reperfused area, as evidenced by the four times greater lactate release in this area compared with the control value. The dual carbon-labeled isotopes showed that 57% of the exogenous glucose entering glycolysis was being converted to lactate. Exogenous glucose contributed to greater than 90% of the observed lactate production. This finding was confirmed by the histochemical finding of sustained glycogen depletion in the occlusion/reperfusion area. The average area of glycogen depletion (37%) significantly exceeded the average area of necrosis (17%). These data demonstrate enhanced and sustained activity of the nonoxidative glycolytic pathway after a prolonged occlusion with reperfusion in canine myocardium. Because glycogen stores remain depleted, exogenous glucose becomes an important myocardial substrate under these pathologic conditions.

Animals↗
PubMed1989

Humoral regulation during cold-induced coronary arterial spasm.

Previous attempts to define the etiology of coronary arterial spasm have been focused on mechanisms such as autonomic nervous dysfunction and/or enhanced platelet activation. In the present study, humoral regulation was investigated in patients with vasospastic angina and scintigraphically documented transient myocardial perfusion abnormalities after a peripheral cold pressor test. Serial changes in angiotensin II, epi- and norepinephrine as well as thromboxane B2 (the stable derivate of thromboxane A2), and malondialdehyde were determined at baseline (I), immediately after 5 minutes cold water hand immersion (II), and following 10 minutes recovery (III). Angiotensin II and epinephrine remained unchanged during observation (I vs II, II vs III: P = NS). Norepinephrine was elevated after cold (I vs II: P less than 0.001) and normalized after 10 minutes (I vs III: P = ns). Thromboxane B2 and malondialdehyde increased continuously (I vs III: P less than 0.05 and I vs III: P less than 0.002, respectively). Further radiothin-layer chromatography results indicate an activation of platelet function during myocardial ischemia. Our results do not establish a cause-effect relationship but, together with other evidence, they may suggest that thromboxane A2 is unlikely to be the cause of spasm. It might, however, play an important role in the maintenance of vasoconstriction.

Angiotensin II↗
PubMed1989

[CHILD syndrome--a case report for understanding this rare genetic dermatosis].

CHILD syndrome in a 4 6/12 years old girl with manifestation of the typical unilateral ichthyosiform erythroderma and hypoplasia of the left arm and leg after birth is reported. The symptoms are listed in a table for comparison to other publications. The moderate shortening of the mother's left arm has significance to the unclear mode of heredity. Local therapy with vitamin A acid brought a satisfactory result. Finally, a short reference is given to a new case from another kindred.

Child, Preschool↗
PubMed1989

[Relation between myocardial perfusion, myocardial necrosis and residual glucose metabolism as a vitality parameter in the post-ischemic myocardium following coronary reperfusion].

The assessment of myocardial viability following interventions aiming at restitution of antegrade blood flow by PTCA and thrombolysis has become one of the most important goals to judge interventional success. Conventional markers as ECG, the extent of the regional wall motion abnormality and enzymes have conceptual limitations. We had shown previously that increased residual glucose metabolism in reperfused myocardium can be assessed by F-18 2-deoxy-glucose (FDG) and positron emission tomography (PET) and will predict functional recovery in reperfused myocardium. The present study introduces a novel concept for the evaluation of myocardial viability by the application of multiple tracer techniques and investigates tracer behaviour in relation to blood flow, regional wall motion, coronary anatomy and histology. The experimental data compare segmental uptake of F-18 FDG with the current most clinically important perfusion marker Tl-201 and Tc-99m (Sn) pyrophosphate (Tc-99mPPi) as a marker of myocardial necrosis in a canine model following a 3 hour intracoronary balloon occlusion and subsequent reperfusion and therefore in a clinically attributable occlusion and reperfusion scenario. Myocardial blood flow was assessed by microspheres, regional fractional tracer retention fractions were evaluated from tissue tracer concentrations, the arterial input function and quantitative blood flow measurements. The extent of ischemic damage was evaluated by TTC post mortem staining, histology, and histochemistry. Additional studies to illucidate the mechanism of increased glucose utilization were done by analysis of other substrates as lactate. The result within the area at risk was assessed in relation to the metabolic behaviour. PET methods were validated in the same dog model as a quantitative biochemical in-vivo assay and imaging procedure and demonstrate the ability of this noninvasive techniques to measure blood flow and myocardial metabolism, especially exogenous glucose utilization. Time dependent and repetitive PET studies may indicate a delayed recovery of myocardial metabolism following an ischemic event with a pattern of a blood flow-metabolism mismatch, characteristic for persistent viability. Metabolic data by imaging correlate with reference techniques as arterio-venous sampling and post mortem histochemical staining method using TTC, PAS, and glycogen techniques. The clinical part applies the proposed tracer concept to patients with acute myocardial infarction and following reperfusion interventions as well using conventional markers and again positron markers. These studies indicate possibilities to assess myocardial viability by the same simultaneou

Aged↗
PubMed1988

[Value of myocardial scintigraphy of coronary anomaly in the differential diagnosis of pediatric cardiomegaly].

The differentiation between anomalous origin of the left coronary artery from the pulmonary artery (ALCAPA) and other causes of cardiomegaly and thereby the decision to operate, as opposed to undertaking conservative therapy is often extremely difficult in clinical practice. Electrocardiographically, signs of myocardial infarction can be missed in ALCAPA, other forms of dilative cardiomyopathy (DCMP) often showing similar clinical features. Up to now aortography alone can make a clear-cut distinction between these two entities. In order to determine the diagnostic value of thallium-201 myocardial scintigraphy in ALCAPA, we investigated 18 children, 7 of them with angiographically or autoptically established ALCAPA and 11 patients with DCMP. The coronary artery anomaly was diagnosed on the basis of the typical myocardial perfusion defects in only 3 of the relevant 7 patients. In 9 of the 11 patients with DCMP ALCAPA was excluded by the homogeneous perfusion pattern or small focal reduction in thallium-201 activity in the left ventricular muscle mass. In view of the overall disappointing results of this method in achieving a specific diagnosis in ALCAPA, all patients with DCMP with or without suspected fibroelastosis should undergo invasive diagnosis with aortography.

Adolescent↗
PubMed1988

Increase of pulmonary vascular resistance during cold provocation in patients with variant angina.

This study was performed to evaluate pulmonary vascular reactivity in patients with angiographically documented coronary vasospasm. Right heart catheterization was performed in 8 subjects with vasospastic angina without evidence of Raynaud's phenomenon: heart rate, systemic and pulmonary arterial pressure as well as cardiac output were determined at rest, during cold provocation and after 20 minutes recovery. Data were obtained both before and during treatment with nifedipine. During cold provocation pulmonary vascular resistance was elevated significantly (P less than 0.02 compared with baseline); systemic vascular resistance tended to increase; nifedipine blunted both vasoconstrictor effects. Our results indicate an abnormal vascular response of the pulmonary arteries to cold provocation in patients with symptomatic coronary artery spasm and suggest a primary vasospastic disorder with coronary and pulmonary manifestation.

Adult↗
PubMed1988

Characteristics of transient ischaemic episodes in patients with silent and symptomatic exercise-induced myocardial ischaemia.

To evaluate transient ischaemic episodes during daily life in patients with coronary artery disease and exercise-induced myocardial ischaemia, 38 patients underwent ambulatory ST-segment monitoring over 48 h. Sixteen patients had painless ischaemia during exercise and occasional angina, and 12 patients had symptomatic ischaemia and frequent angina during daily life. Ten patients with proven coronary artery disease but normal exercise electrocardiograms served as controls. The extent of coronary artery lesions and the prevalence of myocardial infarction were similar in all groups. ST-segment monitoring revealed 817 min and 98 episodes of ST depression in 13/16 patients of the asymptomatic group and 111 min and 21 episodes in 5/12 patients of the symptomatic group (P less than 0.03). Subjective scores for physical activity during Holter monitoring were significantly higher in the first group than in the second. The majority of ischaemic episodes in both groups was asymptomatic. No ischaemic ST changes occurred in control patients. Results indicate a higher frequency of transient ischaemic episodes related to a higher level of physical activity in patients with silent ischaemia than in patients with symptomatic exercise-induced ischaemia.

Angina Pectoris↗
PubMed1987

[Myocardial ischemia with normal coronary vessels. Indication of a vasospastic etiology].

In a 43-year-old woman with ECG changes of an acute anterior and posterior wall infarct, associated symptoms and biochemical findings, coronary angiography demonstrated normal coronary arteries and a normal variant in the course of the left coronary artery. Vasospasms in another vascular bed (migraine) and highly positive 201-Thallium scintigraphy during acral cold provocation speak for coronary spasm as cause of the myocardial ischaemia in this patient.

Adult↗
PubMed1987

Relationship between Tl-201, Tc-99m (Sn) pyrophosphate and F-18 2-deoxyglucose uptake in ischemically injured dog myocardium.

We have previously demonstrated that enhanced glucose utilization in reperfused myocardium as assessed by F-18 2-deoxyglucose (FDG) and positron tomography predicts functional recovery. In this study, we compared segmental uptake of F-18 FDG with that of Tl-201 and Tc-99m (Sn) pyrophosphate (Tc-99m PPi) as conventional markers of tissue viability in seven dogs after a 3-hour intracoronary balloon occlusion and 20 hours of reperfusion. Myocardial blood flow was determined with microspheres. Regional retention fractions were calculated from tracer tissue concentrations, the arterial input function, and blood flow. Ischemic injury was assessed by triphenyltetrazolium chloride (TTC) staining and histologic analysis. At 24 hours, blood flow was 22% lower in reperfused than in control myocardium (p less than 0.05). Uptake of Tl-201 was related linearly to blood flow (r = 0.92), while glucose utilization and Tc-99m PPi were 2.9 (p less than 0.01) and 4.7 (p less than 0.05) times higher in reperfused than in control myocardium. Retention fractions of Tc-99m PPi increased with the degree of ischemic injury, while F-18 FDG uptake was highest in segments with mild cell injury. Thus, in ischemically injured myocardium, Tl-201 primarily reflects blood flow. F-18 FDG as a marker of glucose utilization identifies ischemically injured but viable tissue. The admixture of necrotic cells can be determined with Tc-99m PPi. Our results indicate that a dual tracer approach might best characterize the presence and extent of reversibly and of irreversibly injured tissue in a given myocardial region.

Animals↗