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Biomedical subjects

S Effert

Publications and source records attributed to S Effert.

At least 91 records · Page 5Linked to original sources
PubMed1982

Biomedical engineering in cardiology.

There are numerous and quite controversial opinions on what should be covered by the term 'biomedical engineering'. Therefore, it seems necessary to define and reflect on what biomedical engineering really means. Our definition is: biomedical engineering is the application of engineering sciences in clinical medicine. Several examples of 10 years of cooperation between engineers and physicians in Aachen are presented under the confines of the above definition.

Animals↗
PubMed1981

[Early prognostic implications of haemodynamic findings in acute myocardial infarction (author's transl)].

Investigation of 226 patients with acute myocardial infarction showed that simultaneous assessment of end-diastolic pressure in the pulmonary artery as well as minute volume and arterial blood pressure enable a mostly reliable prognosis to be made. End-diastolic pulmonary artery pressure below 18 mm Hg, remaining so during the first two days of illness, is associated with mortality of around 7%. Initially increased values falling to below 18 mm Hg during the measurements are also linked with a good prognosis. An increase within the first 72 hours, as a consequence of progression of infarction or recurrence, increases mortality to around 23%. In cases where the initially increased end-diastolic pulmonary pressure cannot be lowered constantly, prognosis is also unfavourable due to chronic left heart failure in extensive cardiac infarction. The most certain prediction can be derived from the product of stroke volume and pressure, related to body surface. This stroke-work index does not only reflect pre- and after-loading of the left ventricle values mortality was 4%, rising to 88% with values below 25 g . m/m2. Haemodynamic monitoring is indicated for treatment surveillance particularly with vasodilators. Our results show that in addition a useful prognosis may be derived from the individual haemodynamic situation.

Aged↗
PubMed1981

[Hyperactive carotid sinus reflex (author's transl)].

Following carotid sinus stimulation a hyperactive reflex with ventricular asystole of more than 3 seconds was found in 9 out of 40 asymptomatic patients aged more than 60 years. Results varied considerably between different investigators and different investigation days. Over a period of two years patients with hyperactive reflex did not have a worse prognosis than patients with normal reflex response. Symptoms indicating hypersensitive carotid sinus syndrome had not been observed in a single case. The frequent occurrence of hyperactive carotid sinus reflex and its favourable prognosis and the similarly frequent occurrence of vertiginous attacks due to numerous reasons, in the older age group, do not readily allow for a diagnosis of the hypersensitive carotis sinus syndrome, even when both symptoms occur at the same time. Pacemaker implantation should only be considered when repeated syncope has occurred which cannot be attributed to other causes despite extensive investigations.

Age Factors↗
PubMed1981

Treatment of unstable angina pectoris with percutaneous transluminal coronary angioplasty (PTCA).

Percutaneous transluminal coronary angioplasty (PTCA) was performed in 40 patients (34 male, 6 female; 51.0 +/- 8.5 years) with the typical clinical picture of unstable angina. All had a short history of pain (2.9 +/- 2.0 months), angina at rest, transient ST and/or T wave changes during this period, and little or no enzyme elevations. The patients had a total of 41 stenoses (39 single, one double; one main-stem, 26 left anterior descending, 14 right coronary artery). The degree of the stenoses was 95.5 +/- 4.9% (area method) and 81.8 +/- 10.7% (diameter method). PTCA was successfully performed in 26 cases (63%), reducing the stenoses to 61.5 +/- 12.4% (area method) and 39.1 +/- 10.0% (diameter method). One patient (2.5%) received an immediate bypass operation because of an acute vessel occlusion. Eleven of the 14 not successfully treated patients received an aortocoronary bypass within the next three to 35 days. All still had symptoms of unstable angina. Three patients refused operation. Their treatment consisted of nitroglycerin, beta-blockers and nifedipin. Seventeen of the 26 successfully treated patients were restudied after 4.9 +/- 1.7 months. The degree of stenosis had risen to 69.2 +/- 17.4% (area method). While the stenoses in 12 patients were equal or less than before PTCA, stenosis recurred in five cases. Two patients were successfully retreated. PTCA can be performed with a good early success rate and a low concentration rate in patients with unstable angina. Relief of pain and improvement of blood supply to the jeopardized myocardium can be provided immediately and with a limited amount of expense. The method can therefore be regarded first-stage treatment in such patients.

Adult↗
PubMed1981

Detection of left atrial thrombi by echocardiography.

A group of 111 patients with mitral valve disease was studied by M-mode and two-dimensional echocardiography. Five left atrial thrombi were demonstrated, two of which had probably been the source of previous embolic events. Two-dimensional echocardiography was superior to M-mode in providing spatial orientation. Using multiple cross-sections the exact localisation and the size of the thrombus formation could be estimated. Thrombus localisations at the upper, lateral, and septal atrial walls, normally inaccessible to the single-beam technique, were successfully imaged. Even two-dimensional echocardiography, however, constitutes an imperfect method. By comparison with the findings at surgery only one-third of confirmed thrombi could be detected non-invasively. According to their localisation seven clots in the appendage were missed by the ultrasound method. One further thrombus fixed to the upper left atrial wall near the entrance of the upper pulmonary veins was also undetected by echocardiography. Despite these limitations, the information provided by echocardiography can be most helpful in patient management. M-mode, in combination with two-dimensional echocardiography, is therefore recommended in all patients with mitral stenosis before diagnostic or therapeutic procedures are undertaken.

Adult↗
PubMed1980

[Heart rupture].

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Age Factors↗
PubMed1980

[Cardioversion].

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Atrial Flutter↗
PubMed1980

Left ventricular volume and ejection fraction determination by cross-sectional echocardiography in patients with coronary artery disease: a prospective study.

In a prospective study the accuracy of cross-sectional echocardiography for determination of left ventricular (LV) volume and ejection fraction (EF) was analyzed in 53 patients with coronary artery disease and compared to that of cineangiocardiography (angio). From the apex of the heart phased-array wide-angle (84 degrees) electronic echocardiograms were received in the RAO-equivalent view. Angios were obtained in a 30 degree RAO view. Using Simpson's rule, end-diastolic (EDV) and end-systolic (ESV) LV volumes were calculated and the EF derived. Left ventricular long axis was transected in eight segments, yielding seven diameters. In 50 of the 53 patients cross-sectional echocardiograms could be recorded. The correlation between cineangiocardiography and cross-sectional echocardiography for EDV was highly significant: r = 0.936, y = 0.667x + 27.1, standard error of estimate (syx) +/- 22.2 ml; for ESV: r = 0.970, y = 0.699x + 14.7, syx +/- 14.5 ml; for stroke volume: r = 0.721, y = 0.503x + 11.3, syx +/- 15.3 ml; for EF: r = 0.909, y = 0.740x + 11.3, syx +/- 6.0%. Angio mean long axis was 10.2 +/- 1.2 cm, cross-sectional echocardiographic long axis 8.7 +/- 1.3 cm. Mean LV diameter determined by cineangiocardiography was longer than when determined by cross-sectional echocardiography. The mean difference reached 2.0 cm in the middle of the LV. Our prospective comparative study revealed that LV volumes and EF were underestimated by cross-sectional echocardiography compared to cineangiocardiography because of a methodological systematic error caused by a tangential cut of the heart. In the RAO-equivalent view the "true" long axis was missed. The high corrleation coefficients, however, indicate that the "true" LV volume and EF can be calculated from the given regression equation. Serial measurements should be legitimated.

Angiocardiography↗
PubMed1980

QRS mapping in the evaluation of acute anterior myocardial infarction.

In 42 patients with acute anterior myocardial infarction (AMI), we studied the course of Q-wave development and R-wave reduction during the first 48 hours after the onset of chest pain. We used precordial mapping in relation to clinical features, hemodynamic measurements and enzyme release. Q waves developed within 6-14 hours (mean 9 hours) after onset of symptoms. R-wave amplitudes demonstrated nearly a reflected image: They reduced abruptly 5-11 hours (mean 9 hours) after onset of chest pain, coinciding with ST-segment elevation. In 14 patients (group A, 33%) after initial QRS alterations, there were no further changes. Twenty patients (group B, 48%) had a distinct new increase of Q waves (delta sigma Q = 3.0 +/- 2.0 mV/hours) and further R-wave reduction (-delta sigma R = 1.0 +/- 0.6 mV/hour) simultaneous with new severe chest pain and a delayed second increase of enzyme release corresponding with extension of infarction. There were no significant differences between the groups in age, hemodynamics and infarct size calculated from creatine kinase release. Eight patients (group C, 19%) had contradictory findings. Our findings are consistent with previous results indicating that the critical period for intervention is very small except in patients with extension of necrosis.

Adult↗