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Biomedical subjects

R Slutsky

Publications and source records attributed to R Slutsky.

At least 37 records · Page 2Linked to original sources
PubMed1981

Peak rate of left-ventricular ejection by a gated radionuclide technique: correlation with contrast angiography.

Gated radionuclide cardiac blood-pool imaging can produce reliable estimates of left-ventricular (LV) volume and ejection fraction. The ventricular volume curve can be used to develop normalized ejection rates, since count volumes and framing times are known. To test the accuracy of the peak ejection rate (maximum dv/dt), as derived by a standard computer algorithm, we studied 15 patients with coronary artery disease by both contrast ventriculography and radionuclide angiography. Max dv/dt by the radionuclide technique correlated well with the angiographic result: r = 0.92, p less than 0.01. The mean intraobserver variation was (plus or minus 12%) and the mean interobserver variation plus or minus 0.33 end-diastolic volumes per sec (plus or minus 13%). We conclude that maximum dv/dt may be derived from gated blood images, with reasonable accuracy and modest variability.

Adult↗
PubMed1980

Left ventricular ejection fraction changes during recovery from treadmill exercise: a preliminary report of a new method for detecting coronary artery disease.

To test the value of combining treadmill exercise with radionuclide angiography for detecting exercise-induced left ventricular dysfunction, ejection fractions were calculated at rest, peak supine bicycle exercise, and during three supine post-treadmill recovery periods (2-4 min, recovery 1;4-6 min, recovery 2;8-10 min, recovery 3) in ten coronary artery disease patients and eight normal subjects. Both the normal subjects and coronary artery disease patients had normal resting ejection fractions (greater than 0.50). In the normal subjects the mean ejection fraction increased significantly (p less than 0.005) from rest (0.61 +/- 0.03) to peak supine bicycle exercise (0.71 +/- 0.04), and the mean ejection fraction also remained significantly higher (p less than 0.005) at rest than during 10 min post-treadmill exercise. However, the coronary artery disease patients did not significantly change the mean ejection fractions from rest (0.59 +/- 0.06) to peak supine bicycle exercise (0.55 +/- 0.08), and the average ejection fraction during each one of the post-treadmill recovery periods was not significantly different from rest. At the third recovery period all the normals but no coronary artery disease patients had higher ejection fraction than the resting ejection fraction. We thus conclude that the magnitude of change in ejection fraction from rest to 8-10 min post-treadmill exercise in patients with normal resting ejection fraction may be helpful in identifying those with coronary disease.

Angiocardiography↗
PubMed1980

Influence of different background and left-ventricular assignments on the ejection fraction in equilibrium radionuclide angiography.

Seventy-six patients were studied within one week of contrast ventriculography to assess the influence of differing background assignments on ejection fractions derived from gated equilibrium radionuclide anigograms. "Fixed" and "variable" left-ventricular regions on interest and five different backgrounds were used. Inter- and intra-observer variability were determined, and 15 patients underwent a second study 2 weeks later. Variable left-ventricular regions of interest produced higher ejection fractions than fixed ones. A computer-assigned background or a ring drawn manually around the left ventricle correlated best with contrast ventriculography, giving greater serial and inter- and intra-observer variability. Automated background assignments reduced variability and increased reproducibility, though not always associated with the best correlation with contrast ventriculography. Thus a variety of left-ventricular and background regions of interest gives excellent reproducibility and accuracy.

Adult↗
PubMed1980

First-third ejection fraction at rest compared with exercise radionuclide angiography in assessing patients with coronary artery disease.

To compare two methods of evaluating patients with coronary artery disease, the authors assessed the ejection fraction (EF) during the first-third (1/3) of systole by first-pass radionuclide angiography and the EF response to exercise in 22 normal individuals and 40 patients. The 1/3 EF was calculated by averaging 3--5 beats on the time--activity curve. Exercise EFs were obtained by gated cardiac imaging. The results are shown below, including the per cent change in EF with exercise (% EF). (Formula: see text) p less than 0.05 vs. normals; p less than 0.001 vs. normals; all results are +/- SD. Thirty per cent of patients had a depressed EF, 98% had a depressed 1/3 EF, and 88% had an abnormal EF response to exercise. It is concluded that the 1/3 EF by first-pass radionuclide angiography at rest may be at least as sensitive in identifying patients with coronary artery disease as the EF response to exercise.

Adult↗
PubMed1980

Radionuclide perfusion images before and after cardiac rehabilitation.

Improvement in cardiac perfusion has not been demonstrated in man to explain the increased functional capacity secondary to exercise training. Thallium imaging is a noninvasive method of evaluating myocardial perfusion and scaring. Therefore, using thallium exercise tests, we studied 17 patients with coronary heart disease before and after a mean of 6 months participation in cardiac rehabilitation program emphasizing exercise training. Interobserver variability in imaging interpretation was considered by reading images blinded both individually and in consensus. Agreement with defects called by consensus occurred at least 51% of the time individually and normal readings agreed at least 90% of the time. By consensus reading, seven patients showed improved perfusion, seven showed no change, and three worsened following training. Our study shows that thallium scans may be used to demonstrate central changes in myocardial perfusion after cardiac rehabilitation, but larger controlled studies considering redistribution and utilizing image enhancement are necessary to see if such changes are truly secondary to this intervention.

Adult↗
PubMed1980

Cardiac rehabilitation: evidence for improvement in myocardial perfusion and function.

Sixteen patients with coronary heart disease (CHD) were studied with rest and exercise thallium scans and gated radionuclide ventriculography before and after 3 to 12 months of exercise training. The 5 patients presented in this report showed improvement in both the ejection fraction and exercise thallium images after training while achieving a higher maximal workload and an equivalent double product. These radionuclide techniques have provided the 1st documentation of improvement in both myocardial perfusion and function in CHD patients after exercise training. A controlled study using advances in imaging technology with patients matched according to postmyocardial infarction time and by the severity of disease is underway to confirm these findings.

Adult↗
PubMed1980

Differential diagnosis of atypical chest pain syndromes by equilibrium radionuclide angiography during exercise.

In order to describe exercise-induced changes of left ventricular function in patients with atypical chest pain and to determine the diagnosis accuracy of radionuclide angiography in the differential diagnosis of various chest pain syndromes, we studied a consecutive series of 26 patients and 20 healthy volunteers. Only patients with ejection fractions > 0.50 at rest, without antianginal therapy and without a prior myocardial infarction who eventually underwent diagnostic left heart catheterization were included in the study. In all healthy volunteers ejection fraction increased during exercise by at least 10% over the resting level (from 0.61 +/- 0.05 to 0.76 +/- 0.07; P < 0.001). A similar ejection fraction response was found in 14 of the 26 patients (group A): ejection fraction increased from 0.60 +/- 0.06 to 0.72 +/- 0.07 (P < 0.001), whereas in the remaining 12 patients (group B) ejection fraction decreased from 0.62 +/- 0.06 to 0.57 +/- 0.07 (P < 0.01). Left heart catheterization revealed normal coronary arteries in 13/14 group-A patients while 10/12 group-B patients had significant coronary artery lesions (> 50%). The other two group-B patients were found to have idiopathic cardiomyopathies. We conclude that normal subjects with atypical chest pain during exercise have a normal ejection fraction response to exercise despite their symptoms and that therefore radionuclide angiography during exercise is a valuable noninvasive method in the differential diagnosis of exercise-induced chest pain syndromes.

Adult↗
PubMed1979

Assessment of early ventricular systole by first pass radionuclide angiography: useful method for detection of left ventricular dysfunction at rest in patients with coronary artery disease.

To identify abnormal left ventricular function without exercise stress in patients with coronary artery disease first-pass radionuclide angiograms were analyzed in 32 normal subjects (Group I); 31 patients with coronary disease and normal contrast ventriculograms (Group II); and 17 patients with coronary disease and depressed left ventricular function (Group III). Total ejection fraction (EF) was computed with standard angiographic methods and from each time-activity curve. During the first third of systole, ejection fraction was determined manually by averaging three to five beats and the value compared with that obtained with contrast ventriculography: (Formula: see text). Both total radionuclide ejection fraction (r = 0.95) and first-third ejection fraction (r = 0.91) correlated well with angiography. Intraobserver and interobserver variation was small, averaging 0.02 +/- 0.02 (range 0 to 0.05). The radionuclide first-third ejection fraction was 0.25 or greater in normal subjects and less than 0.25 in 29 of 31 patients (94 percent) in Group II and in all patients in Group III. It is concluded that the first-third ejection fraction obtained with first pass angiography identifies subtle abnormalities of left ventricular function at rest in more than 90 percent of patients with coronary disease that may not be recognized by total ejection fraction alone.

Adult↗
PubMed1979

Reproducibility of ejection fraction and ventricular volume by gated radionuclide angiography after myocardial infarction.

To validate the repeated use of radionuclide equilibrium angiography for determining left ventricular (LV) ejection fraction (EF) and end-diastolic and end-systolic volumes (EDV and ESV), 25 patients were studied on an hourly basis an average of 9.1 days after acute myocardial infarction. Data were processed with a semi-automatic computer program which develops an averaged-volume curve from an assigned LV region-of-interest. LV EDV and ESV were derived from a previously described method which correlates well with contrast angiography (r = 0.977, y = 0.0255x - 0.121). Comparison between initial and subsequent equilibrium EF and between initial and subsequent volumes showed excellent correlation. Excluding three anginal episodes, the EF variation between studies averaged 0.03 +/- 0.02.

Acute Disease↗