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Biomedical subjects

P Block

Publications and source records attributed to P Block.

At least 55 records · Page 3Linked to original sources

Radionuclide evaluation of left ventricular synergic pumping efficiency during acute myocardial infarction.

The clinical value of an index of left ventricular synergic pumping efficiency (EFF) was evaluated in 50 patients with uncomplicated myocardial infarction in which radionuclide ventriculography was performed within 72 h of the onset of the infarction and between 7 and 13 days post infarction. EFF was defined as the ratio of global left ventricular stroke volume to the magnitude of all intraventricular blood pool variations measured on a pixel by pixel basis. EFF correlated better with a subjectively evaluated wall motion index (r = 0.84) than did the ejection fraction (EF) measurements (r = 0.69). In all patients, but most significantly in patients with inferoposterior infarctions, EFF measurements in the acute phase were a better predictor of the predischarge ventricular performance than the EF measurements. The left ventricular EFF is a reliable parameter to quantitate the effect of regional wall motion disturbances on global ventricular function in a standardized manner.

Adult↗

Comparison of the echocardiographic and hemodynamic diagnosis of rheumatic tricuspid stenosis.

Two-dimensional echocardiography has proved to be reliable in the diagnosis of mitral, aortic and pulmonary stenosis. Its role in the diagnosis of rheumatic tricuspid stenosis is still being defined; therefore, the tricuspid valve echograms of 147 patients with rheumatic heart disease were examined. Thirty-eight of these patients also underwent hemodynamic evaluation. Tricuspid stenosis was defined echocardiographically as diastolic anterior leaflet doming, thickening and restricted excursion of the other two tricuspid leaflets and decreased separation of the leaflet tips. Using these criteria, the sensitivity and specificity of the echocardiogram in detecting tricuspid stenosis were 69 and 96%, respectively, in the group of 38 patients who had both echocardiographic and hemodynamic evaluations. However, when the smaller group of 17 patients who had simultaneous right atrial and right ventricular pressure recordings were considered separately, there was complete agreement between the echocardiographic and hemodynamic data. Thus, the two-dimensional echocardiogram is a sensitive and specific test for diagnosing rheumatic tricuspid stenosis. In addition, these data provided an opportunity to determine the prevalence of tricuspid stenosis in this group of patients with chronic rheumatic valvular disease. Tricuspid stenosis was present in 14 (9.5%) of the total group of 147 patients who had two-dimensional echocardiograms, and in 10 (26.3%) of the 38 who had both echocardiographic and hemodynamic studies. In patients with rheumatic heart disease about to undergo cardiac catheterization, an echocardiographic study should prove useful in making the diagnosis of tricuspid stenosis.

Adult↗

Bronchogenic carcinoma: a rare cause of nontraumatic pneumopericardium.

The history of a 67-year-old woman presenting a sudden nontraumatic pneumopericardium is reported. Investigation revealed that this patient had developed a bronchopericardial fistula secondary to a bronchogenic carcinoma. The clinical diagnosis was confirmed at autopsy. Although it is fairly evident that in this case the pneumopericardium could be related to the bronchogenic carcinoma, only a few reports of such an association have been published in the literature.

Aged↗

Toward the optimal lead system and optimal criteria for exercise electrocardiography.

To define the optimal lead system for exercise electrocardiography, data of the whole body surface potential distribution were analyzed in 25 normal subjects and in 25 patients with coronary artery disease at rest and during exercise. All patients had a normal electrocardiogram at rest. The sensitivity of the standard chest leads was 60 percent; it improved to 84 percent with the body surface map whereas both methods had a 100 percent specificity. On the basis of these data, and reports from other centers, it is concluded that a single bipolar lead from the right subclavian area to lead V5 is adequate in those laboratories that are restricted to testing subjects with a normal electrocardiogram at rest. In patients with a previous infarction or other abnormalities in the electrocardiogram at rest three (pseudo) orthogonal leads or several standard leads are necessary. Recommendations for optimal measurements from the exercise electrocardiogram are based on quantitative computer analysis of the selected leads in larger groups of patients. Best results were obtained with a combination of S-T amplitude, S-T slope and heart rate. The improvement in sensitivity from 50 percent with visual analysis to 85 percent with computer was similar to that obtained with body surface mapping. Changes of the P wave and QRS complex during exercise appeared to be of little diagnostic value. The pathophysiologic mechanisms that contribute to the changes of the electrocardiogram during exercise are discussed.

Adult↗