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Biomedical subjects

R Standke

Publications and source records attributed to R Standke.

At least 19 recordsLinked to original sources
PubMed1994

Coronary artery stenosis and occlusion: value of 99Tcm-MIBI SPECT.

The aim of this study was to evaluate and validate a new quantification method for 99Tcm-sestamibi single photon emission computed tomographic (SPECT) myocardial imaging based on a four-slice analysis method and to check the functional results of percutaneous transluminal coronary angioplasty (PTCA). Using the calculated pathological area of the scintigram as an index for myocardial ischaemia, the overall sensitivity was 81-90% and the overall specificity was 74-98%. Analysis of variance of the repeated measurements revealed good reproducibility (coefficient of variation 8.4%). A significant correlation was found between the size of the exercise-induced perfusion defects and the degree of coronary stenosis. The comparison of radionuclide ventriculography and the perfusion image in 27 patients revealed a good correlation between the resting global ejection fraction and myocardial perfusion, but there was no correlation during exercise, indicating a dissociation between myocardial perfusion and function during exercise conditions in patients with coronary artery disease (CAD). Patients with total coronary occlusions showed more resting defects than patients with partial stenoses. Both groups benefit from PTCA or re-opening of chronic coronary occlusion, respectively. Exercise-induced myocardial ischaemia significantly decreased, and in 36% of the patients with previous myocardial infarction a significant reduction of the size of the resting perfusion defects occurred. In conclusion, our quantification method is suitable for the accurate non-invasive diagnosis of CAD, and for the follow-up of the invasive treatment of coronary artery stenoses and occlusions.

Adult↗
PubMed1992

Effect of propranolol and disopyramide on left ventricular function at rest and during exercise in hypertrophic cardiomyopathy.

In 19 patients with hypertrophic cardiomyopathy (15 males, 4 females, mean age 49.2 +/- 10.8 years) left ventricular function was studied with radionuclide ventriculography at rest and during exercise in a crossover design without intervention and after disopyramide and propranolol treatment. 15 of the 19 patients had a resting or latent intraventricular gradient of more than 30 mm Hg. Left ventricular function at rest and during exercise was evaluated before medication, 90 min after oral administration of 200 mg disopyramide or 160 mg propranolol and after 3 weeks of oral therapy with disopyramide 200 mg 2 times a day or propranolol 80 mg 4 times a day. After long-term treatment with disopyramide, resting ejection fraction decreased from 72 +/- 12 to 69 +/- 14% (p less than 0.01) and peak ejection rate (PER) decreased from 3.46 +/- 135 to 3.24 +/- 65 end-diastolic volume (EDV).s-1 (p less than 0.01). Peak filling rate (PFR) at rest decreased from 3.01 +/- 0.8 to 2.77 +/- 0.63 EDV.s-1 (p less than 0.05). Time to peak filling rate (TPFR) at rest and during exercise after acute and chronic therapy did not change compared to control values. Acute and long-term administration of propranolol lead to a significant reduction in heart rate at rest and during exercise.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗
PubMed1991

[Improved left ventricular function and perfusion at rest following transluminal coronary angioplasty].

The purpose of this study was to evaluate left ventricular function and perfusion at rest before and after percutaneous transluminal coronary angioplasty. In consecutive 69 patients in whom coronary stenoses were dilated, the radionuclide left ventricular ejection fraction at rest increased significantly. In 26 of these patients, the ejection fraction increased by at least 4%. In these patients, exercise-induced ischemic ST depression had been more pronounced than in the others. 36 other patients underwent 201TI myocardial scintigraphy before and after angioplasty. Twelve patients in whom pre-PTCA images had revealed regions with irreversible 201TI uptake defects, showed normal 201TI distribution patterns on post-PTCA scintigrams. Post-exercise 201TI uptake (representing myocardial perfusion and metabolic activity) during pre-PTCA exercise stress tests was significantly lower in these cases. It is concluded that PTCA can improve left ventricular function and perfusion at rest. This improvement is most obvious in patients with pronounced exercise-induced myocardial ischemia as diagnosed by typical ST segment depression and reduced thallium uptake.

Adult↗
PubMed1991

[Multiparametric analysis using radionuclide ventriculography in the assessment of left ventricular function following heart transplantation].

Left ventricular systolic and diastolic performance was evaluated by radionuclide angiography in 17 patients following cardiac transplantation and compared with normal persons. Both groups performed supine bicycle exercise during the investigation, the control group at 102 +/- 73 W and the transplanted patients at 61.2 +/- 15 W. The ejection fraction increased in the normal persons from 61 +/- 8 to 69 +/- 10% whereas in the transplanted patients it did not increase significantly. There were no relevant changes in systolic parameters during exercise in the transplant recipients. The changes in diastolic parameters were significantly smaller in transplant patients than in normals. After correction for heart rate-induced changes a significantly different time course of the systolic-diastolic sequence during the cardiac cycle became evident in the transplanted group at rest. During exercise the systolic-diastolic sequence during the cardiac cycle became similar in both groups. It is concluded that the reduced exercise capacity of patients in the late phase after cardiac transplantation is partially due to the absence of an EF increase and a limitation of diastolic reserve during exercise.

Adult↗
PubMed1990

[Normal values in equilibrium radionuclide ventriculography. Results of a multicenter study].

The Working Group on Cardiovascular Nuclear Medicine of the German Society of Nuclear Medicine has organised a multi-center study in which 13 institutes in the FRG participated. Data on equipment and methods employed in equilibrium radionuclide ventriculography and on results in 585 non-cardiac patients were obtained by means of a questionnaire. The global left-ventricular ejection fraction amounted, on average, to 64% but there were significant differences between participating institutes, probably due to differences in the selection of subjects and in the methods used. The majority of institutes reported an increase in EF by more than 10% after an ergometric workload of more than 100 W. End diastolic, end systolic and stroke volume agreed well throughout. However, whereas peak ejection and peak filling rates at rest showed good agreement between institutes, those after exercise differed widely, probably also because of differences in methods.

Gated Blood-Pool Imaging↗
PubMed1988

[Comparison of effort-ECG and radionuclide ventriculography in relation to the detection of myocardial ischemia in isolated stenoses of the anterior interventricular branch].

21 patients with LAD-stenoses of at least 70% and 21 patients with LAD-stenoses and additional intramural anterior wall infarctions were studied. 20 patients without heart disease or after successful transluminal coronary angioplasty and 18 patients with intramural anterior wall infarction after successful transluminal dilatation of the LAD (remaining stenosis maximal 30%) served as controls. The normal range of global and regional left ventricular ejection fraction response to exercise was defined based on the data of 25 further patients without relevant coronary heart disease. Thus, a decrease in global ejection fraction and regional wall motion abnormalities were judged pathological. All patients were comparable with respect to age, ejection fraction at rest and work load. Myocardial ischemia could be detected by the exercise ECG in 81% of all patients without infarction and in 71% of patients with infarction. The corresponding values for global left ventricular ejection fraction were 76% and 81%, respectively, and for regional ejection fraction 95% in both groups. No false-positive exercise ECGs were observed in the healthy controls and 2 (11%) in the corresponding group with intramural infarction. The global ejection fraction was pathological in 1 (5%) healthy subject without infarction and in 3 (17%) corresponding patients with infarction. Sectorial analysis revealed 5 and 22%, respectively. Our findings suggest that the exercise ECG has a limited sensitivity to detect myocardial ischemia in patients with isolated LAD-stenoses and intramural myocardial infarction. Radionuclide ventriculography yields pathological values more often; however, false-positive results also occur more frequently.

Adult↗
PubMed1987

[Chronic aortic insufficiency: prediction of postoperative course based on preoperative relations of left ventricular end-diastolic volume to regurgitated blood volume].

The range of appropriate left ventricular dilatation due to volume overload was defined in 21 patients with a stable course of chronic aortic regurgitation, by correlating the scintigraphically determined left ventricular end-diastolic volume with the regurgitated blood volume. 25 other patients with chronic aortic regurgitation, who were scheduled for valve replacement, were within this normal range (group 1); in nine patients, left ventricular end-diastolic volume exceeded the amount expected from the amount of regurgitation (group 2). Patients were followed up between 2 and 62 months postoperatively (average: 26 +/- 13 months). No patients from group 1, but four out of nine patients from group 2 (45%) died postoperatively from congestive heart failure. In 23 out of 24 patients from group 1, left ventricular ejection fraction was postoperatively within the normal range, although preoperative values had been severely depressed in three cases (lower than 40%). Ejection fraction remained depressed in one patient with persistent mitral regurgitation and in all patients from group 2. Global heart volume significantly decreased by 20% in group 1, whereas only minor changes (-15%) were observed in group 2 (group 1: from 1184 +/- 186 to 954 +/- 120 ml, 2p less than 0.001; group 2: from 1402 +/- 300 to 1185 +/- 294 ml). This was compared to the course of left ventricular end-diastolic diameter (group 1: from 7.1 +/- 0.9 to 5.5 +/- 0.7 cm (-23%), 2p less than 0.001; group 2: from 7.6 +/- 0.7 to 6.9 +/- 1.3 cm (-9%). In group 1, left ventricular ejection fraction significantly increased, whereas no significant changes were observed in group 2 (group 1: from 53 +/- 13 to 64 +/- 13% (+21%), 2p less than 0.001; group 2: from 29 +/- 7 to 32 +/- 14% (+10%]. It is concluded that the scintigraphically determined ratio of left ventricular end-diastolic volume to regurgitated blood volume provides important prognostic and functional information regarding the postoperative course of chronic aortic regurgitation. This ratio is more reliable than single radionuclide, electrocardiographic, roentgenographic or echocardiographic parameters.

Adult↗
PubMed1987

Radionuclide ventriculography: acute and chronic response to verapamil in patients with hypertrophic cardiomyopathy.

Eleven patients with hypertrophic cardiomyopathy were investigated by repeated radionuclide ventriculography. Nine of them were studied for the first time while under long-term treatment for 14 to 84 months. In all eleven patients radionuclide ventriculography was performed after a withdraw of verapamil for at least 14 days or before the onset of therapy respectively (control period). A third investigation was carried out 60 to 90 min after acute administration of 90 mg oral verapamil. A last radionuclide ventriculography was performed following 2 weeks of therapy with 480 mg oral verapamil. After acute administration heart rate significantly increased from 69 +/- 10 to 80 +/- 15/min. EDV was in the normal range. Left ventricular global ejection parameters showed no significant changes except for minimal decrease in ejection time from 309 +/- 29 to 278 +/- 50 ms after acute verapamil administration. The sectorial ejection fraction improved in apical sectors in relation to the basal one, while the global EF remained constant. The ventricular global peak filling rate increased significantly from 283 +/- 61 to 325 +/- 64%/EDV/s after acute administration of verapamil and the sectorial peak filling rate increased in apical sectors compared to basal sectors following acute administration as well as long-term therapy. After withdrawal of verapamil, six out of 11 patients showed a homogeneous left ventricular delay of contraction by means of the Fourier phases which were normalized under short- and long-term verapamil treatment. In conclusion, verapamil caused a marked improvement of the left ventricular contraction delay without significant changes in global systolic function.

Acute Disease↗
PubMed1987

[Nuclear medicine in determining the shunt in ductus arteriosus Botalli].

In 9 patients with patent ductus arteriosus, quantification of left-to-right shunt was performed with dye dilution curves after peripheral injection and with radionuclide ventriculography. The study was repeated within 7 days after successful transluminal occlusion of the ductus with an Ivalon-plug. Reproducubility of the method could be studied in one patient in whom reopening of the ductus occurred. Dye dilution curves were analyzed using the method of Carter et al. Radionuclide ventriculography was performed as a combined first-pass and equilibrium study: effective stroke volume was derived from the first pass of the tracer through the heart; during the equilibrium phase left ventricular ejection fraction (EF) and left ventricular enddiastolic volume (EDV) were evaluated. The difference between total left ventricular stroke volume (product of EF and EDV) and effective stroke volume was taken as shunt volume. This volume as a fraction of total left ventricular stroke volume resulted in percent left-to-right shunt. The sensitivity of the dye technique was 78%; a quantification of the shunt lesion was possible in 55% of all cases (shunt greater than 35%). The sensitivity of the radionuclide technique was 90%. The severity of the lesion could not be determined in one patient with a minimal shunt. After successful occlusion of the ductus, dye dilution curves normalized in all cases. Radionuclide ventriculography showed normalization in all but one patient. This patient with concomitant mitral regurgitation still showed moderate left ventricular volume overload.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1986

[Results of combined myocardial scintigraphy and radionuclide ventriculography before and after transluminal coronary angioplasty of critical coronary artery stenoses].

This study compares exercise radionuclide ventriculography (RNVG) and exercise myocardial scintigraphy with 201Tl (MSC) both computed trisectorially. 137 patients before and after transluminal angioplasty (TCA) were investigated. While specificity equivalent was set at 90% for both methods (10% percentile of the controls [n = 29]) overall sensitivity for RNVG was 79% (n = 86) and for MSC 78% (n = 98). Sensitivity of RNVG for lesions of the posterior wall was lower than for the anterior wall: LAD stenoses 83% (n = 46), RCA stenoses 71% (n = 17), and LCX stenoses 63% (n = 8). Sensitivity of MSC presents only a slight difference between anterior and posterior wall lesions: LAD stenoses 78% (n = 51), RCA stenoses 73% (n = 22), RCX stenoses 100% (n = 8). Reproducibility of pathological findings before and after non-successful TCA and the determination of the stenosed vessel was slightly better with MSC than with RNVG. Functional improvement after a successful TCA is predictable by MSC, whereas RNVG documents the functional improvement.

Adult↗
PubMed1986

[Effect of captopril in chronic aortic insufficiency].

In 16 patients with chronic aortic regurgitation, we studied the acute hormonal and hemodynamic effects of 12.5 to 25 mg captopril; in 12 patients the changes after a 4 to 8 week treatment period (mean 6.3 +/- 2 weeks; doses: 3 times 12.5 to 3 times 25 mg/day) were investigated. The following baseline variables were evaluated: the radionuclide left ventricular ejection fraction (EF) at rest and during exercise, left ventricular end-diastolic volume (EDV), regurgitant blood volume (RBV); and plasma renin activity (PRA). Repeated determinations of EF, EDV and RPA were carried out 90 minutes after application of the drug. In patients with chronic therapy, EF at rest and during exercise, EDV, RBV and PRA were reinvestigated at the end of the study. Acute administration of captopril was followed by an increase of EF (from 49 +/- 12 to 55 +/- 12%, p less than 0.001) and a slight decrease of EDV (from 389 +/- 160 to 376 +/- 146 ml, p less than 0.05). PRA significantly increased (from 1.6 to 3.1 ng/ml/h, p less than 0.05). Chronic therapy resulted in a moderate decrease of systolic and diastolic blood pressure (from 156/70 +/- 31/15 to 140/63 +/- 23/15 mm Hg, p less than 0.01). However, no significant changes were observed in EF at rest and during exercise (51 +/- 9 vs. 53 +/- 10% and 45 +/- 14 vs. 47 +/- 14%), EDV (433 +/- 179 vs. 422 +/- 179 ml) and RBV (136 +/- 81 vs. 129 +/- 77 ml). PRA was significantly increased (6.3 ng/ml/h, p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Aortic Valve Insufficiency↗
PubMed1986

[Persisting volume overload of the left ventricle following surgical correction of chronic aortic insufficiency].

After aortic valve replacement for chronic aortic regurgitation, complete normalization of the left ventricular end-diastolic volume can rarely be observed. We therefore investigated the role of continual volume overload caused by persisting concomitant mitral regurgitation. 20 patients who received an aortic valve for chronic aortic regurgitation (group 1), 5 patients after operation for aortic stenosis (group 2) and 6 patients with double valve replacement because of aortic and mitral valve lesions were included in the study 1 to 108 months after operation. All patients were examined clinically and by combined first pass/equilibrium radionuclide ventriculography. In the case of significant regurgitation (greater than 20%) 2-dimensional colour-coded Doppler-echocardiography was performed in patients of group 1 to localize the regurgitant lesion. 15 patients of group 1 had a typical systolic murmur indicating mitral regurgitation. 14 of these patients had significant scintigraphic left-sided heart regurgitation: 7 patients had regurgitant fractions between 21 and 40%; 6 patients between 41 and 60%; in 1 patient RF was 64%. Echocardiography confirmed mitral regurgitation in 9 of 11 of these cases. No significant regurgitation was observed in patients of group 2; mild regurgitation was measured in 5 of 6 patients of group 3 (26 to 31%). We conclude that in patients with chronic aortic regurgitation complete normalization of the left ventricular end-diastolic volume after valve replacement may not occur in some patients because of persisting mitral regurgitation.

Aortic Valve Insufficiency↗