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Biomedical subjects

P Schweizer

Publications and source records attributed to P Schweizer.

At least 91 records · Page 5Linked to original sources
PubMed1983

[Quantification of the function of the left ventricle using 2-dimensional echocardiography].

Left ventricular volumes and the ejection fraction can be determined by two-dimensional echocardiography. Because of methodological problems, cineventriculographic normal values can not be transferred to two-dimensional echocardiography. Therefore, normal values for two-dimensional echocardiographically determined left ventricular volumes and the ejection fraction were established in 55 normal controls. Basing on these volumes, the sensitivity and specificity of two-dimensional echocardiography for detection of impaired left ventricular function was analysed and compared with results from cineventriculography. Sensitivity for detection of a reduced ejection fraction was 84%, specificity 89% and predictive accuracy 98%. Thus, two-dimensional echocardiography can be used as a screening method for analysing left ventricular function. Analysis of beat-to-beat variation revealed that for two-dimensional echocardiography 3 consecutive beats should be analysed because evaluation of 5 instead of 3 beats increased reliability only by less than 1%. It was necessary to analyse the day-to-day variations. To separate a random error from a non-random error for an individual change, an absolute change of volumes of more than 10-12% and of ejection fraction of more than 10% had to be observed. Group changes can of course be smaller and yet significant. Intraobserver variation was not significant and below 5%. However, interobserver variability must be considered. This depends on observer experience. For a 4-chamber view no significant variability was observed, but for the RAO-equivalent view the observer variation was significant for end-diastolic and end-systolic volume. For the ejection fraction no significant difference was found. Two-dimensional echocardiography can be used for pharmacodynamic studies if percentage changes instead of absolute changes are listed.

Cardiac Output↗
PubMed1983

[Gated blood pool scanning in the diagnosis of coronary disease. A prospective study to compare cineventriculography and 2-dimensional echocardiography].

38 patients with clinically suspected coronary artery disease were studied by contrast ventriculography, 2-dimensional echocardiography and multiple gated blood pool imaging (MUGA) without stress. The results were compared with each other and with the final diagnosis confirmed by coronary angiography. The left ventricular ejection fraction is evaluated nearly identically and with sufficient accuracy by both non-invasive methods, local motion abnormalities are on the other hand diagnosed in the best way by MUGA imaging in our own cases.

Adult↗
PubMed1983

Echoventriculography -- a simultaneous analysis of two-dimensional echocardiography and cineventriculography.

Two-dimensional echocardiography underestimates left ventricular volume compared with cineventriculography. To exclude the influence of difference in heart rate, blood pressure, respiration phases and any effect of the contrast material on left ventricular function, simultaneous studies of two-dimensional echocardiography and cineventriculography-echoventriculography were performed in 46 patients. Apical two-dimensional echocardiograms in the right anterior oblique (RAO) equivalent view were recorded before and during cineventriculography in the 30 degrees RAO projection. End-diastolic and end-systolic volumes (EDV and ESV) were calculated using a disc method with a semiautomatic computer system. The echo transducer position relative to the left ventricular apex and long axis was analyzed. For EDV determined by two-dimensional echocardiography and cineventriculography, the linear regression equation was y = 0.659x + 0.8, SEE = +/- 26.2 ml, r = 0.907. For ESV, the regression equation was y = 0.571x + 17.8, r = 0.938, SEE = +/- 18.6 ml, and for ejection fraction (EF) it was y = 0.606x + 13.0, r = 0.803, SEE = +/- 9.1%. Injection of contrast material resulted in only a small increase of stroke volume, caused by an increase of EDV as analyzed by echoventriculography. In all but two patients, the transducer position was found to be anterior and superior to the left ventricular anatomic apex, as evaluated by filming the echo transducer position during cineventriculography in 46 patients in the 30 degrees RAO projection and in 15 patients consecutively in the 60 degrees left anterior oblique and 30-40 degrees cranial projections. Thus, tangential cuts of the ventricle resulted in underestimation of diameters, long axis and ventricular volumes. These methodologic problems are exacerbated by slice-thickness artifacts. Furthermore, different outlining of left ventricular contour -- outer border of ventricular trabeculae for cine ventriculography and inner border for two-dimensional echocardiography -- seemed to result in underestimation of volume by echocardiography.

Adult↗
PubMed1983

Malignant ovarian tumours during childhood.

Malignant ovarian tumours in childhood are rare. Germinal cell tumours are the most common tumours and are extremely malignant, with the exception of dysgerminomas. The possibilities of therapy have improved considerably in the last 3 to 4 years, thanks to combined chemo- and radiotherapy following surgical resection of the tumour. Exact staging at the beginning of therapy is very important. A second operation, primary or as a second look procedure, is recommended after emergency operations. Therapy should be carried out in pediatric oncology centres. Because of the invasive measures, medical and psychological care are necessary after the conclusion of therapy. The rarity of these tumours should prevail upon us to organize national and international therapeutic studies.

Adenocarcinoma↗
PubMed1982

[Apical two-dimensional echocardiography: normal values for single- and bi-plane determination of left ventricular volume and ejection fraction].

A difference was obtained between cineventriculography and 2-D echocardiography in the determination of left ventricular volume and ejection fraction. Normal values obtained by the former could not be used for the latter. The authors, therefore, determined their own normal values. Apical 2-D echocardiography was used for the normal group (35 males, mean age 30.2 years; 20 females, mean age 26.2 years). In addition to mean values and standard deviations, one-sided tolerance limits (T) were calculated, separating the normal range from abnormal within 95% confidence limits for 90% of the total group. End-diastolic and end-systolic volume index in males was 66.8 +/- 8.8 ml/m2 compared with 26.9 +/- 5.2 ml/m2 on biplane evaluation. Tolerance limits were calculated at 82.0 and 35.9 ml/m2, respectively. Stroke volume index was 39.9 +/- 7.0 ml/m2, T = 27.8 ml/m2, ejection fraction 59.2 +/- 6.0%, T = 48.8%. End-diastolic and -systolic volume index for females had a mean of 60.7 +/- 12.5 ml/m2, T = 85.0 ml/m2, and 25.7 +/- 7.4 ml/m2, T = 40.1 ml/m2, respectively. Stroke volume index was 56.5 +/- 10.6 ml/m2, T = 35.9 ml/m2, the ejection fraction 58.1 +/- 6.5%, T = 45.5%. Between monoplane and biplane measurements of apical 2-D echocardiograms there was no significant difference. Normal values for volume and ejection fraction of the left ventricle, determined from apical four-chamber and RAO-equivalent cuts make it possible to categorize the function of the heart and to provide the basis for further studies of the sensitivity and specificity of the method.

Adolescent↗
PubMed1982

[Ventricular septal defect in acute myocardial infarction].

Ventricular septal rupture is the fourth-common cause of death after cardiac arrhythmia, acute congestive failure and rupture of the cardiac wall in acute myocardial infarction. Generally it can be easily diagnosed by a systolic jet sound in the 4th and 5th intercostal space parasternally on the left side. Differential diagnostic difficulties occur in the acute phase of infarction regarding papillary muscle rupture. Myocardial rupture does not occur immediately after the onset of the pectanginous state and not within the first day of illness, but generally within the first week. Vasodilatory treatment permits only short-term stabilisation of vascular problems, however, time is made available for diagnostic measures, usually catheterisation of both sides of the heart and coronary angiography. Immediate operation and occlusion of the defect, if necessary accompanied by a saphenous vein bypass, is presently considered treatment of choice. Out of the three patients with this complication the ruptured site could be occluded surgically in two, one of whom had severe cardiogenic shock. Shock symptoms regressed immediately and the postoperative course was unremarkable. In the third patient no operation was performed due to his age of 77 years and general vascular sclerosis. He died of cardiogenic shock 11 hours after admission to hospital.

Aged↗
PubMed1982

[Right heart failure after infarction of the right ventricle (author's transl)].

The right ventricular filling pressure was raised above 10 mm Hg in 20 cases (12%) out of 175 patients haemodynamically monitored in the acute phase after cardiac infarction. The end-diastolic pulmonary arterial pressure was not above 18 mm Hg so that in these cases an extensive necrosis of the right ventricle must be assumed to be the cause of right heart failure. In 75% of these patients with predominantly right sided infarction there was a posterior wall infarct whereas in patients with left heart failure the anterior wall was significantly more often affected. Patients with posterior wall infarction and right heart failure had more commonly infarct signs in the right precordial chest leads Vr3 to Vr6 and an increased diameter of the right ventricle in the echocardiogram than patients with posterior wall infarction but without right heart failure. However, a definite separation of the two groups was not possible with these non-invasive techniques. Haemodynamic changes should thus be decisive for the diagnosis of predominantly right heart infarction as these dictate the treatment.

Adult↗
PubMed1982

Haemodynamic effects of prenalterol in patients with severe congestive heart failure--NYHA III-IV.

In 12 patients with severe congestive heart failure due to ischaemic heart disease (n = 6) and due to congestive cardiomyopathy (n = 6) the haemodynamic effects of a new beta 1-agonist, prenalterol, were studied. Left ventricular (LV) function was studied before and 20 min after infusion of 12 mg prenalterol. Heart rate was kept constant by atrial pacing at a rate of 100 min-1 unless intrinsic heart rate exceeded it. As a sign of positive inotropic support, prenalterol enhanced peak rate of LV pressure development (dP/dt) from 1160 +/- 100 mm Hg/s to 1590 +/- 190 mm Hg/s (p less than 0.005). In the mean LV end-diastolic and end-systolic volume determined by cineventriculography and two-dimensional echocardiography decreased. LV stroke work index measured with both methods increased with 4 ml/m and 5 ml/m, respectively (p less than 0.02). LV ejection fraction was improved by 6% and 8% (p less than 0.005). Increase of peak fall of left ventricular pressure (dP/dt) (1050 +/- 60 mm Hg/s to 1270 +/- 100 mm Hg/s, p less than 0.005) and shortening of time constant (T) of pressure fall from 64.5 +/- 5.0 ms to 44.5 +/- 6.0 ms (p less than 0.005) demonstrated the improved LV relaxation. Analysis of LV volume and myocardial compliance revealed decrease of left ventricular stiffness. Thus, LV filling pressure was reduced from 22.1 +/- 4 mm Hg to 14 +/- 3.5 mm Hg (p less than 0.001). Pressure volume analysis showed a significant increase of LV power and work, as well as a slight decrease of wall stress. Our study could demonstrate, even in patients with severe heart failure, a sustained positive inotropic effect of prenalterol leading to an improved left ventricular contractility, relaxation and compliance. LV power and work was enhanced. The increase of oxygen demand seemed to be counterbalanced by an improved perfusion of particularly subendocardial layers indicated by an increased transmyocardial pressure gradient.

Adrenergic beta-Agonists↗
PubMed1982

Morphometric investigations in mitral stenosis using two dimensional echocardiography.

A method is proposed for comparing the orifice size and the morphology of stenotic mitral valves, removed intact at the time of replacement, with the preoperative two dimensional echocardiographic cross-sections. The excised mitral valve apparatus is suspended on a specially constructed mounting. To avoid shrinkage the orifice is stabilised with an airfilled balloon. A radiography is taken directing the x-ray beam perpendicular to the valve orifice. In 40 of 51 patients this method provided the means of relating the echocardiographic cross-sections to the morphology of the valve. Planimetry of the valve area compared favourably with the postoperatively determined orifice size. Agreement was found in 34 of 40 patients in orifice shape between preoperative echocardiograms and x-rays of th excised valve. The relation between intraoperative estimation of size of the valve, using dilators with known diameters, and the postoperative results was less favourable. Areas of calcification were identified on echocardiography as dense conglomerate echoes. In 30 patients (75%) the localisation of calcium deposits and in 67% the degree of calcification was in agreement with the x-rays of the valve taken after operation. In addition to determination of the area, two dimensional echocardiography allows detailed studies of the stenotic valves, and is of particular importance for planning operative treatment.

Adult↗
PubMed1982

[Right ventricular volume determination by two-dimensional echocardiography and radiography in model hearts using a subtraction method].

The irregularity and complexity of the right ventricle is the reason why no accurate method for right ventricular volume determination exists. A new method for right ventricular volume determination particularly for two-dimensional echocardiography was developed-it is called subtraction method-and was compared with the pyramid and Simpson's methods. The partial volume of the left ventricle and septum was subtracted from total volume of right and left ventricle including interventricular septum. Thus right ventricular volume resulted. Total and partial volume were computer-assisted calculated by use of biplane methods, preferably Simpson's rule. The method was proved with thinwall silicon-rubber model hearts of the left and right ventricle. Two orthogonal planes in the long-axis were filmed by radiography or scanned in a water bath by two-dimensional echocardiography equivalent to RAO and LAO-projections of cineangiocardiograms or to four- and two-chamber views of apical two-dimensional echocardiograms. For calculation of the major axes of the elliptical sections, summed up by Simpson's rule, they were derived from the LAO-projection and the four-chamber view, respectively, the minor axis approximated from the RAO-projection and the two-chamber view. For comparison of direct-measured volume and two-dimensional echocardiographically determined volume, regression equation was given by y = 1.01 x -3.2, correlation-coefficient, r = 0.977, and standard error of estimate (SEE) +/- 10.5 ml. For radiography, regression equation was y = 0.909 x + 13.3,r = 0.983, SEE = +/- 8.0 ml. For pyramid method and Simpson's rule, higher standard errors and lower correlation coefficients were found. Between radiography and two-dimensional echocardiography a mean difference of 4.3 +/- 13.2 ml, using subtraction method, and -10.2 +/- 22.9 ml, using pyramid method, as well as -0,6 +/- 18.5 ml, using Simpson's rule, were calculated for right ventricular volume measurements. Differences were not significant. The subtraction method seems to be useful for calculation of right ventricular volume by radiography as well as two-dimensional echocardiography. Further studies in isolated hearts and patients are necessary for final judgment of the accuracy of this new method.

Blood Volume↗
PubMed1982

[Value of contrast echocardiography in the diagnosis of tricuspid insufficiency].

Contrast echocardiography utilizing peripheral saline injection was used for the detection of tricuspid regurgitation in 127 patients. In 36 patients prior to contrast echocardiography a tricuspid regurgitation was documented by angiography of the right ventricle. A V-wave synchronous pattern of contrast appearance in the inferior vena cava was detected by subcostal transducer position in 34 patients, and in 27 patients retrograde systolic flow lines across the tricuspid valve were documented by left parasternal transducer position. Correlated with angiographic data, the sensitivity of the method in the detection of a tricuspid regurgitation was 97% and the specificity 100%. False positive findings consisted in A-wave synchronous patterns and in heart-cycle-independent patterns of contrast appearance. Vena caval ultrasonography using size, pulsation, and inspiratory decrease in dimension was not helpful in predicting tricuspid regurgitation. A diameter of the inferior vena cava less than 10 mm/m2 BSA was indicative of normal right ventricular function.

Adult↗