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Biomedical subjects

P Knesewitsch

Publications and source records attributed to P Knesewitsch.

28 records · Page 2Linked to original sources
PubMed1987

Combined evaluation of first pass radionuclide angiography and equilibrium radionuclide ventriculography in the diagnosis of coronary artery disease. II. Results during exercise.

Results of 203 patients who underwent first pass radionuclide angiography (FP) and quantitative equilibrium radionuclide ventriculography (qERNV) were stored in a data base system and evaluated statistically. Eighty eight of these patients also underwent exercise equilibrium radionuclide ventriculography (E-qERNV). In patients with coronary artery disease (CAD) without previous myocardial infarction (MI), evaluation of global and regional ejection fraction (gEF, rEF) at rest revealed a poor sensitivity of 64%, the specificity was about 71% (qERNV). FP at rest revealed similar values of sensitivity (69%) and specificity (83%). Additional assessment of stress induced changes of gEF, significantly (P less than 0.05) improved sensitivity of qERNV in CAD patients without a history of previous MI to 84% (specificity 86%). In patients with one previous MI, however, similar values of sensitivity were found (R-FP: 87%, R-qERNV: 84%, E-qERNV: 93%). In patients with several MI's, sensitivity was above 90% at rest and during exercise (R-FP: 96%, R-qERNV: 93%, E-qERNV: 100%).

Coronary Disease↗
PubMed1987

[Evaluation of adriamycin cardiotoxicity using equilibrium radionuclide ventriculography. I. Results at rest].

Results of 606 equilibrium radionuclide ventriculographies performed in 348 non-selected patients receiving Adriamycin (ADM) therapy were stored in a data base system. The aim of the study was to assess the influence of a potential cardiotoxic therapy on left ventricular pump function. Increasing ADM doses yielded a significant (p less than 0.05) decrease of the resting ejection fraction (R-gEF), the peak ejection rate and the peak filling rate. End diastolic and end systolic volumes increased significantly. Stroke volume, heart rate and time to peak filling rate did not change significantly. 368 follow-up studies were performed in 128 patients: 65/128 patients presented a decrease of R-gEF, but only in 45 of these patients R-gEF values fell into the pathologic range. In 44 of these follow-ups, R-gEF remained unchanged. In 19 patients, a R-gEF increase was observed. At the beginning of ADM therapy 14% of the patients had subnormal R-gEF values. With increasing ADM doses pathologic findings increased to 86% in patients with ADM doses higher than 500 mg/m2.

Adult↗
PubMed1987

[Evaluation of adriamycin cardiotoxicity using equilibrium radionuclide ventriculography. II. Results during exercise].

The aim of the study was to evaluate the influence of a cardiotoxic therapy with Adriamycin (ADM) on left ventricular pump function. In 348 patients with malignant tumors, 606 equilibrium radionuclide ventriculographies (ERNV) were performed. In 90 patients, resting studies (R-ERNV) were followed by studies during exercise (E-ERNV). Results were evaluated statistically to determine whether E-ERNV provides more reliable parameters in the early detection of Adriamycin cardiomyopathy (ADM-CMP) than R-ERNV. The following left ventricular parameters were evaluated: global ejection fraction (gEF); end diastolic, end systolic, stroke volume (EDV, ESV, SV); peak filling rate, peak ejection rate (pFR, pER); time to peak filling rate (TpFR) and heart rate. Increasing ADM doses yielded a significant decrease (p less than 0.05) of resting values of gEF, pER, pFR. In contrast, stress-induced increases of gEF, pER, pFR were found independent of accumulative ADM doses and independent of the resting values of these parameters. An increase of gEF resulted from a significant decrease of ESV. In most cases, pathologic results at rest were detected earlier than subnormal changes of exercise values. Therefore, E-ERNV does not have a significantly higher sensitivity in the early detection of ADM-CMP than R-ERNV and is not required for the surveillance of patients under ADM therapy.

Adult↗
PubMed1986

Combined evaluation of first-pass radionuclide angiography and equilibrium radionuclide ventriculography in the diagnosis of coronary artery disease. I. Results at rest.

The results of 203 patients who underwent first-pass radionuclide angiography (FP), as well as quantitative equilibrium radionuclide ventriculography (qERNV), were stored in a data base system and evaluated statistically. In patients with coronary artery disease (CAD) without previous myocardial infarction (MI), evaluation of global and regional ejection fraction (gEF, rEF) at rest revealed a poor sensitivity of 64% (Rest-qERNV) and 69% (Rest-FP), respectively. In patients with a history of one previous MI, the sensitivity of both methods was equivalent: FP 87% and qERNV 84%. In patients with several MIs, sensitivity was higher than 90%. Concerning localization of MI, remarkable differences between FP and qERNV were found. In posterior wall infarction, the FP sensitivity was 87% and qERNV only 67%, whereas in anterior wall infarction, the results were similar for both methods: 93% (FP) and 96% (qERNV), respectively. Since 30 degrees RAO camera position achieves the best visualization of the anterior and posterior wall, FP is superior to qERNV in the evaluation of posterior wall asynergies. In addition, qERNV often fails to discriminate anterior and posterior wall motion abnormalities.

Coronary Disease↗
PubMed1985

[Effect of body loading on the specific blood radioactivity following 99mTc in-vivo erythrocyte labelling. The effects on determining end-diastolic volume in equilibrium radionuclide ventriculography].

In 40 patients who underwent stress-equilibrium-radionuclide-ventriculography, we examined the stress-induced change of blood radioactivity concentration. A significant (p less than 0.025) increase of blood radioactivity concentration after peak exercise (mean +7.2%) was found. This increase was the result of a significant (p less than 0.025) increase of the hematocrit (mean +4.7%) due to a decrease of the plasma volume. The changes of radioactivity concentration and hematocrit neither show any correlation with peak exercise value, integral exercise or duration of exercise, nor with the increase of heart rate or blood pressure. The increase of end-diastolic volume appears to result largely from a stress-induced increase of blood radioactivity concentration. Thus, radioactivity concentration should be measured before and after exercise when evaluating volume changes caused by stress-equilibrium-radionuclide-ventriculography.

Cardiac Output↗
PubMed1984

[Quantitative resting radionuclide-ventriculography for multifactorial analysis of left ventricular function].

Results from 388 patients, examined with quantitative equilibrium radionuclide ventriculography (qERNV) at rest, were stored in a data bank system and evaluated statistically. The value of time and velocity parameters [ejection time (ET), filling time (FT), time ES to peak filling rate (TpFR), mean (mER) and peak (pER) ejection rate, peak filling rate (pFR)] were evaluated in patients with coronary heart disease (CHD, with and without history of earlier myocardial infarction) or with cardiomyopathy (CMP). Significant (p less than 0.025) changes vs. normal in CHD I/II were obtained from pER, pFR, ET, in CHD III from gEF, EDV, mER, pER, pFR, in CHD IV from gEF, EDV, mER, pER, pFR, in patients with infarction or with CMP from gEF, EDV, mER, pER, pFR, ET and TpFR. Resting qERNV revealed a sensitivity in diagnosing a CHD (stages I-III) by mER of 30-59%, by pER of 40-65%, by pFR of 48-60% and by ET of 58-61%, which was higher than the sensitivity of gEF (19-56%).

Cardiac Output↗
PubMed1984

[Quantitative equilibrium radionuclide ventriculography at rest in the evaluation of the severity of coronary disease].

The results of examining 373 patients with a quantitative equilibrium radionuclide ventriculography were stored in a data bank and evaluated statistically. The following left ventricular parameters were evaluated: global and regional ejection fractions ( gEF , rEF1 - rEF5 ) and volume parameters (EDV, ESV, stroke volume, cardiac output, heart index). It appeared that in stages I and II of coronary heart disease evaluation of gEF , EDV and ESV under resting conditions does not sufficiently discriminate diseased patients from normals. Significant changes (p less than 0.025) of these parameters (vs. normal) were found only in CHD III and IV or in patients with a history of old myocardial infarction. The additional evaluation of the regional fraction yields, however, a significant increase (CHD I and II: +25%) of the sensitivity of the equilibrium radionuclide ventriculography in the diagnosis of coronary heart disease.

Coronary Disease↗
PubMed1981

[First-tracer passage with a single-crystal gamma camera: completed assessment of left-ventricular function by determining enddiastolic volume, regional ejection fraction and %-akinetic segment (author's transl)].

Determination of left ventricular (LV) enddiastolic volume (EDV) was achieved by calibration of the system (single-crystal gamma camera, equipped with a converging collimator) to a volume phantom (egg). A good correlation (r = 0.92) was found with EDV values, obtained from cineventriculography. Images, derived from enddiastole (ED) and endsystole (ES) were corrected for background by "parabolic background subtraction", which is a realistic form of background correction in view of the LV-shape. Regional ejection fraction (REF) was calculated by an electronical operation using the ejection fraction formula and these ED and ES images. REF values reflect regional or segmental LV pump function and are superior to one- or two-dimensional parameters (e.g. visual assessment of asynergy, hemiaxis shortening) since REF values include the third dimension by referring to regional volumes. In addition, per cent-akinetic segment may be replaced by REF. Results from the literature show that first-tracer passage with a single crystal gamma camera at rest (n = 534) yield equivalent results in comparison with cineventriculography. Therefore, this nuclear procedure may be routinely used. REF values complete the diagnostic parameter as yet available.

Cineradiography↗