PubMed Health⌕ Search

Biomedical subjects

E L Ritman

Publications and source records attributed to E L Ritman.

At least 145 records · Page 8Linked to original sources
PubMed1978

Relation between left coronary artery stenosis and regional left ventricular function.

The effect of stenosis of the left main and proximal anterior descending coronary arteries on anterior left ventricular wall dynamics was investigated in 70 patients with ischemic heart disease by the use of roentgen videometric analysis of left ventricular angiograms. In all patients with ischemic heart disease, mean values for peak rate of systolic wall thickening and diastolic wall thinning were significantly smaller than normal (P less than 0.01). In patients without infarction, there was no correlation between peak rate of systolic anterior wall thickening and stenosis of the coronary artery supplying it, but there was a significant reduction in peak rate of diastolic wall thinning (P less than 0.01) in patients with stenosis greater than 90%; this difference was not apparent at any lower degree of stenosis. This population could not be recognized by any other parameter of global or regional ventricular function; thus, diastole is more sensitive to regional left ventricular dysfunction than systole.

Adult↗
PubMed1978

Quantitative imaging of the structure and function of the heart, lungs, and circulation.

A 28-x-ray-source, cylindrical-scanning, transaxial tomographic x-ray-imaging system is in the process of being fabricated. This system will scan synchronously up to 250 parallel transverse cross sections of the human body over an axial range of 25 cm within 0.01 second at a maximum rate of 60 scans per second. The system will provide numerous variations of scanning configurations to permit quantitative assessment of the relative importance of transverse section thickness, image contrast, spatial and temporal resolution, and related computerized algorithms and display techniques. Synchronous imaging at high temporal resolution of a three-dimensional volume--for example, the heart--eliminates the need for successive periods of breath-holding and gated imaging techniques and is essential for quantitation of cardiovascular and pulmonary function and structure in intact animals or humans. Initial clinical applications are expected to be in the early detection of lung cancer and the diagnosis of the nature and degree of congenital and acquired cardiovascular disabilities.

Animals↗
PubMed1977

Survival predictors in coronary artery disease. Medical and surgical comparisons.

Linear discriminant function analysis was used to test the independent prognostic value of nine variables in patients with coronary artery diseaase. For 68 medically treated patients who met the criteria for inclusion in the discriminant function analysis, the most reliable predictor of 2-year survival status was the left ventricular ejection fraction. The prognostic value of the ejection fraction was not improved by the addition of the number of vessels diseased. Comparisons of the survival of 130 medical and 284 surgical patients were made using subsets based on the ejection fraction. When the ejection fraction was greater than or equal to 50%, the probability of 4-year survival was high for both medical (91%) and surgical (96%) groups. When the ejection fraction was less than 25%, the probability of 2-year survival was low in both groups. However, for patients with ejection fraction 25 through 49%, the surgical patients had a better chance (P less than 0.05) for a 3-year survival (89%) than did medical patients (68%). This study emphasizes the prognostic significance of the left ventricular ejection fraction, which should be considered in any comparison of survival in medically and surgically treated patients.

Age Factors↗
PubMed1977

Complete occlusion of the left main coronary artery and the importance of coronary collateral circulation.

Study of four patients who survived complete occlusion of the left main coronary artery forms the basis of conclusions concerning the functional significance of coronary collateral circulation. Each of these patients had prominent collateral circulation from the right coronary artery. Global left ventricular function was maintained to the extent that congestive heart failure did not occur; the biplane ejection fraction was normal in the two patients where measurement was possible. The peak rate of systolic wall thickening by roentgen videometry in anterior left ventricular segments was normal in one patient and mild to moderately depressed in another. Experience with the patients described herein indicates that coronary collateral flow can provide critically needed circulatory support for the patient with coronary artery disease.

Collateral Circulation↗
PubMed1976

Videometric analysis of regional left ventricular function before and after aortocoronary artery bypass surgery: correlation of peak rate of myocardial wall thickening with late postoperative graft flows.

The peak rate of systolic wall thickening (pdTw/dt) in regions of the left ventricle was determined by biplane roentgen videometry in 60 patients before and a median of 14 mo after aorto-coronary bypass graft surgery. The left ventricular ejection fraction, stroke volume, and end-diastolic volume and pressure did not change significantly after surgery in the presence of patent or occluded grafts (P greater than 0.05). Statistically significant increases occurred in the peak rate of systolic wall thickening regions supplied by patent bypass grafts, and significant decreases occurred in regions with occluded grafts (P less than 0.01). Of 42 preoperatively hypokinetic regions (pdTw/dt greater than 0 less than 5.0 cm/s) supplied by a patent graft, 30 improved by an average of 2.6 cm/s after operation; 18 returned to normal. Failure of 24 hypokinetic regions to improve to normal was associated with myocardial infarction in 11 or with late postoperative graft blood flows of less than 60 ml/min measured by videodensitometry, in 10. All seven preoperatively akinetic (pdTw/dt=0) or dyskinetic (pdTw/dt less than 0) regions did not improve after the operation despite the fact that, in five of the seven, coronary bypass flows were over 60 ml/min. All eight preoperatively hypokinetic regions supplied by coronary artery graft flows of less than or equal 40 ml/min failed to improve to normal after operation. All nine preoperatively hypokinetic regions supplied by coronary artery graft flows of over 60 ml/min improved to normal after surgery. Late postoperative coronary artery bypass graft flows, the functional status of the myocardium, the status and distribution of the native coronary circulation, and decreased regional function elsewhere in the ventricle must all be considered when regional left ventricular function is interpreted.

Adult↗
PubMed1975

Regional left ventricular wall dynamics before and after sublingual administration of nitroglycerin.

Regional wall dynamics of the left ventricle before and after sublingual administration of 0.6 mg of nitroglycerin were determined from left ventricular angiograms in 27 patients undergoing coronary arteriography. Regional wall dynamics were quantitatively measured from 60/sec determinations of wall thickness and derived peak rate of systolic wall thickening (peak dTw/dt) in selected sites of the left ventricle. A total of 70 regions were studied. Analysis of the same segment before and after administration of nitroglycerin revealed that the mean change in peak dTw/dt was +1.97 cm/sec in segments with an initial peak dTw/dt of less than 5 cm/sec, in contrast to a change of +0.66 cm/sec in segments with an initial control value of 5 cm/sec or greater. Akinetic or dyskinetic areas did not show improvements after nitroglycerin. In 11 left ventriculograms, an area that was initially hypokinetic manifested an increase in rate of wall thickening after nitroglycerin. The mean increase in peak dTw/dt in anterior segments with electrocardiographic evidence of myocardial infarction was 0.18 cm/sec (P less than 0.05) after nitroglycerin, compared with a mean change of 1.33 cm/sec in anterior segments without such evidence. This study presents evidence for a regional myocardial response to nitroglycerin with differing responses within the same ventricle apparently depending upon the functional state of the underlying myocardium.

Aged↗
PubMed1975

Left ventricular function and myocardial contractility: analysis by roentgen videoangiographic techniques.

Conventional attempts to derive indices of myocardial contractility from left ventricular pump function appear to be unsound in practice and theory, and the small number of dimensional measuremets on which these computations are based obscure the regional differences in ventricular myocardial function. It is not surprising that these indices have not proved to be fully satisfactory, either in research or in clinical laboratory settings. Both theoretical considerations and laboratory results support the need for more detailed measurements of regional myocardial function. These can be obtained by use of multiplanar videoroentgenographic techniques for cross-sectional reconstructions of the epicardial and endocardial surfaces of the heart throughout the cardiac cycle and the application of computer-based sophisticated methods of analysis, such as the finiteelement technique, as a basis for more accurate assessment of myocardial function.

Angiography↗