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Biomedical subjects

H Schelbert

Publications and source records attributed to H Schelbert.

26 records · Page 2Linked to original sources
PubMed1977

Interventricular septal motion and left ventricular function after coronary bypass surgery: evaluation with echocardiography and radionuclide angiography.

To evaluate interventricular septal motion and left ventricular function after coronary bypass graft surgery, 40 patients were studied early postoperatively and serially for up to 16 months with echocardiography and radionuclide angiography. Early after operation mean left septal excursion decreased significantly from 4.6 +/- 0.4 (standard error) to 0.8 +/- 0.6 mm (P less than 0.001), and left septal motion was abnormal in 23 of the 40 patients. Mean right septal excursion reversed from 2.1 +/- 0.5 to -2.1 +/- 0.5 mm early after operation in the 22 patients in whom these measurements could be made, and 15 patients showed paradoxical right septal excursion. At a mean of 4 months after operation, only 7 of 35 patients followed up had abnormal left septal motion, and mean left septal excursion had returned toward normal (3.6 +/- 0.7 mm); mean right septal excursion remained reversed (--1.1 +/- 0.7 mm), and 6 of the 14 patients followed up had paradoxical motion. In the 22 patients whose wall thickness could be measured, mean septal thickening during systole decreased significantly from 35 +/- 4 to 21 +/- 3 percent early after operation (P less than 0.01). During late follow-up septal thickening returned toward normal (32 +/- 4 percent). Mean normalized posterior wall velocity increased significantly after operation from 0.76 +/- 0.03 to 1.01 +/- 0.05 sec-1 (P less than 0.001), but posterior wall thickening remained unchanged. Left ventricular end-diastolic dimension and the radionuclide-determined left ventricular ejection fraction were unchanged postoperatively. It is concluded that (1) echocardiographically detected abnormal septal movement is frequent early after coronary bypass graft operation; (2) both decreased myocardial contraction in the septum and increased anterior movement of the whole heart contribute to this abnormality; (3) the abnormalities in septal movement decrease during late follow-up in many patients but persist in some patients; and (4) posterior wall function tends to increase early after operation and therefore overall left ventricular function remains normal.

Adult↗
PubMed1977

Detection of perioperative myocardial damage after coronary artery bypass graft surgery.

In order to evaluate methods for detecting peri-operative myocardial damage we studied 41 patients before and serially following coronary artery bypass graft surgery utilizing the 12-lead ECG, serum MB-CPK measurements, and 99mTc pyrophosphate myocardial scans. Six of the 41 patients (15%) developed persistent new Q waves after surgery. Six other patients demonstrated ischemic ST-T wave changes that persisted for 48 hours or more. Mean total MB-CPK released was highest for the group with new Q waves [1598+/-545 (SE) I.U./L-hr] as compared to the group with ischemic ST-T wave changes 708+/-65 I.U./L-hr) or the group with no ECG changes (262+/-47 I.U./L-hr). Ten patients (24%) has positive postoperative pyrophosphate scans consistent with myocardial infarction. The three techniques were compared in these 41 patients utilizing 465 I.U./L.-hr as the upper limit of normal MB-CPK released after uncomplicated coronary bypass surgery (no ECG changes, negative scan). Five patients with ischemic ECG changes had a positive scan and high MB-CPK; six patients with no ECG changes had high MB-CPK but a negative scan; and one patient with high MB-CPK and new Q wave had a negative scan. We conclude 1) new Q waves on ECG underestimate the incidence of myocardial damage after coronary artery surgery; 2) MB-CPK alone overestimates the incidence of infarction; and 3) a combination of the three techniques is the best means for detecting myocardial damage after coronary artery bypass graft surgery.

Adult↗
PubMed1977

Noninvasive assessment of left ventricular performance in patients with chronic obstructive pulmonary disease.

In patients with chronic obstructive pulmonary disease (COPD), the clinical differentiation between dyspnea due to left ventricular dysfunction and that due to pulmonary events is difficult. Invasive techniques have been the only reliable diagnostic approach. To assess the potential value of noninvasive techniques in this context, 27 patients with COPD and with clinically suspected left ventricular dysfunction were studied by echocardiography, radionuclide angiography, and right cardiac catheterization. In 20 (74%), adequate echocardiogram were obtained. Of these 20 patients, 17 had normal pulmonary arterial wedge pressures at rest and during submaximal handgrip exercise. Sixteen of these 17 had normal left ventricular performance by all three echocardiographic criteria used; in one patient, two criteria were not interpretable, but the third was normal. Results of radionuclide studies were normal in 15 patients, borderline in one, and not measurable in one. Of the three patients with abnormal wedge pressures, at least one echocardiographic criterion was abnormal in all. Radionuclide data were abnormal in two and not measurable in one. We conclude that left ventricular dysfunction is infrequently present in patients with COPD in whom such dysfunction is clinically suspected, that the two noninvasive techniques described here can be applied successfully to a high percentage of patients with COPD, and that the agreement among echocardiographic, radionuclide, and wedge pressure data is excellent.

Aged↗
PubMed1977

Comparison of 131I-tetracycline and 67Ga-citrate as abscess localizing agents.

Previous studies have shown that radiolabeled tetracyclines tend to accumulate in infarcts and necrotic tumors. These results suggested that radiolabeled tetracyclines might also accumulate in necrotic abscesses or areas of inflammation. In order to develop a better abscess scanning agent, we compared the efficiency of 131I-tetracycline with 67Ga-citrate in labeling experimentally induced staphylococcal aureus abscesses in rats 24 and 72 hours after injection. In addition to evaluating 131I-tetracycline as an abscess scanning agent, we hoped to obtain data which might clarify the controversy regarding early versus late gallium scanning in suspected infection. 131I-tetracycline was chosen over 99mTc-tetracycline because the longer half-life of 131I would allow 72 hour imaging. Absolute concentrations of gallium in the abscess contents and in the surrounding areas of inflammation were significantly greater than the concentration of 131I-tetracycline at both 24 and 72 hours. With the exception of blood, muscle, and bone, the abscess-to-tissue activity ratios for gallium and 131I-tetracycline were similar; however, the ratio of gallium activity in the inflammed tissue to other tissues was greater than that of 131I-tetracycline for every tissue examined at both time periods. The data suggest that 131I-tetracycline has little potential as a general abscess scanning agent. The gallium tissue concentrations and tissue ratios suggest that abscesses which can be imaged at 72 hours can probably be imaged at 24 hours, thus allowing earlier initiation of appropriate therapy. Because of the higher lesion-to-blood ratio at 72 hours, a 72-hour scan would appear to be indicated before a scan is interpreted as normal.

Abscess↗
PubMed1975

Left ventricular performance assessed by radionuclide angiocardiography and echocardiography in patients with previous myocardial infarction.

In 61 patients (77 studies) who had a transmural myocardial infarction, we compared the left ventricular ejection fraction by echocardiography with the ejection fraction determined by a computerized radioisotope technique that makes no assumptions regarding left ventricular geometry. In 31 studies of 26 patients with normal left ventricular wall motion by videotracking and normal left heart size, ejection fraction averaged 0.57 +/- 0.09 (SD) by ultrasound and 0.62 +/- 0.10 by the isotope method. Measurements of ejection fraction by both techniques correlated well (r = 0.86) and there was complete separation between patients with normal and reduced ejection fraction. In 46 studies of 35 patients in whom left ventricular wall motion abnormalities were recorded by videotracking, ejection fraction by the isotope method averaged 0.46 +/- 0.08, while average echo ejection fraction was 0.62 +/- 0.12. The correlation between the ultrasound and isotope methods in these 46 studies was poor (r = 0.33) and in 28 studies measurement of the ejection fraction by the two techniques was discordant. In 26 of the 27 studies where there was a reduced ejection fraction by the isotope method and a normal ejection fraction by echo, the dyssynergy involved the anterolateral left ventricular wall. These data indicate that echocardiographic measurements frequently overestimate left ventricular performance in patients with previous myocardial infarction associated with anterolateral wall motion disorders.

Acute Disease↗