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Biomedical subjects

W Bleifeld

Publications and source records attributed to W Bleifeld.

At least 181 records · Page 10Linked to original sources
PubMed1979

[Left ventricular relaxation and filling abnormalities in patients with HOCM and left ventricular pressure overload (author's transl)].

In order to test the hypothesis that delayed mitral valve opening (MO) with regard to endsystolic dimension (t DS-MO) is specific for hypertrophic obstructive cardiomyopathy (HOCM), LV echograms of patients with different forms of LV hypertrophy due to chronic pressure overload (CPO; aortic stenosis + arterial hypertension, n = 24) and hypertrophic obstructive cardiomyopathy (n = 24) were recorded, digitized and compared with those of normals (N :n = 28(. In patients with HOCM (93 +/- 37 ms; p less than 0.0001) and CPO (66 +/- 31 ms; p less than 0.0001) the time t DS-MO was significantly delayed compared with N (13 +/- 15 MS), due to abnormal relaxation. This prolonged relaxation time resulted in an abnormal diameter increase (delta D) during the isovolumic relaxation phase (HOCM: 4.0 +/- 2.2 MM/CPO: 3.0 +/- 1.8 mm; p less than 0.0001/N:0.6 +/- 0.5 mm) and the rapid filling phase (HOCM 7.6 +/- 2.7 mm; p less than 0.0001/CPO 9.2 +/- 2.9 mm; p less than 0.05 / N: 10.7 +/- 2.2 mm). The echocardiographical signs of an abnormal relaxation are not specific for HOCM, they can be seen in different forms of secondary LV hypertrophy and are accompanied by changes in the diastolic filling pattern.

Adolescent↗
PubMed1979

[Measurement of regional and global coronary sinus blood flow with the continuous thermodilution technique. I. Method and experimental studies (author's transl)].

Experiences from 233 coronary sinus blood flow measurements with the Ganz continuous thermodilution technique are reported. Experimental studies revealed: 1. Because of incomplete isolation of the external thermistor against injectate one has to take into account a systematic error in the range of 3--4%. 2. If flow exceeds 200 ml/min, injection rate must be increased from 30--40 ml/min to 60--70 ml/min for complete mixing of blood and injectate. Then flow rates up to 450 ml/min may be measured precisely. 3. Using the double thermistor catheter experimental studies indicated complete mixing of blood and injectate between injection orifice and first external thermistor. 4. To avoid right atrial admixture the external thermistor should be positioned 3 cm deep into the coronary sinus. 5. It is easier to obtain an identical catheter position within the great cardiac vein, when repeated measurements at different days are necessary. Compared with other measuring methods of myocardial blood flow this technique is inexpensive and simple. It permits rapid changes in coronary sinus blood flow to be studied. The possibility to determine simultaneously myocardial substrate utilisation is of great advantage.

Blood Flow Velocity↗
PubMed1978

[Reversible myocardial ischaemia or irreversible myocardial fibrosis? Differentiation by biphasic 201thallium scintigraphy (author's transl)].

The results of biphasic 201thallium (201Tl) scanning were compared with those of coronary arteriography, left ventricular angiogarphy and stress ECG in 56 patients with coronary artery disease and six with no evidence of heart disease. There were 104 201Tl defects, 50 of them reversible. The defects were always located in the area supplied by a critically stenotic coronary artery. Correlation of regional wall motion with 201Tl activity demonstrated that in all forms of abnormal wall motion there was either ischaemia or fibrosis. The resting LV angiogram thus does not make it possible to distinguish between myocardial ischaemia and fibrosis. Taking the LV angiogram as a standard, the rate of false-positive 201Tl scintigrams was 5%, that of false-negative ones 23%. The biphasic 201Tl scintigram was more sensitive than the stress ECG in detecting myocardial ischaemia. It furthermore made it possible to localize the ischaemic (or fibrotic) region within the LV and to estimate its size.

Adult↗
PubMed1978

[Abnormal left-ventricular contraction and filling in patients receiving adriamycin for solid tumours (author's transl)].

Various ventricular functions, as obtained by echocardiography (M-mode), were measured on 14 patients with solid tumours receiving adriamycin (mean total dosage 330 +/- 188 mg/m2 body surface area), the results being compared with those on 14 normal subjects of similar ages. There were statistically highly significant differences between the two groups. In those receiving the drug there was (1) a decrease in the percentage shortening fraction and (2) a reduction in the maximal velocity of endocardial circumferential fibre shortening, as expression of reduced contractility. The abnormal filling was characterized by a marked decrease in maximal velocity of endocardial fibre stretch, diminution of diameter increase during the rapid filling phase, and a shortened duration of the rapid filling phase. There was no electrocardiographic or radiological evidence of myocardial damage. The findings suggest that it will be possible by serial echocardiography to recognize a higher tolerance to the drug in some individuals and, at the same time, reveal abnormal contractility and filling due to adriamycin before irreversible heart failure has occurred.

Adult↗
PubMed1978

[Short-term localized myocardial ischaemia and its consequences in Prinzmetal angina pectoris (author's transl)].

In a 45-year-old female patient with Prinzmetal angina pectoris coronary angiograms and a 201thallium scintigram were performed during an ergotamine-induced episode of angina. The spontaneous and the ergotamine-induced attacks were characterized by transient ST elevation in the posterior wall ECG leads. The coronary angiogram during the attack showed spasm of the circumflex branch of the left coronary artery. In the 201thallium scintigram a large defect in myocardial thallium uptake was noticed in the posterior wall of the left ventricle. Angina and ECG abnormalities disappeared within 4 minutes. However, the scintigraphic defect disappeared only after 6 hours. The slow recovery of myocardial thallium uptake is thought to represent an alteration of the myocardium after a brief 4 minute interruption of regional coronary arterial blood flow. The diagnostic approach in patients with Prinzmetal angina is discussed.

Angina Pectoris↗
PubMed1978

[Evaluation of infarct size using serum concentration of the CK-MB isoenzyme (author's transl)].

The size of infarction was determined in 21 patients with acute myocardial infarction aged 42 to 76 years using serial analyses of the serum concentrations of the total creatine kinase (CK) and of the CK-MB isoenzyme. CK-MB isoenzyme concentrations reached their maximum in serum three hours earlier on average and returned to the initial value 10 to 12 hours before the total CK. CK-MB isoenzyme concentrations reached a maximum of 12.4% of maximum total CK activity. In 17 uncomplicated cases the infarct weight determined from total CK (40 +/- 23 g) and from CK-MB isoenzyme (35 +/- 23 g) was only different by 5 g (r = 0.92). In 4 patients with infarction and defibrillation or reanimation use of total CK led to an overestimation of the infarct size by more than double. The determination of the infarct size from CK-MB isoenzyme values proves that without extracardial CK release, estimation of the infarct size can also be done sufficiently exactly from the total CK concentrations. In complicated cases, however, the specific myocardial CK isoenzyme makes determination of the infarct size possible

Acute Disease↗
PubMed1978

Education and professional training of biomedical engineers in West Germany.

The health service and educational systems, together with industry and research centres, are the primary institutions involved in the development of the bio-engineering profession in West Germany. Since industry and research institutions in West Germany are similar in structure to those in other countries, for the purposes of international comparison only the health service and educational systems are described. The questions "how many bioengineers are needed?" and "how many should be trained?", were the motivation for a professional field analysis commissioned by the German Society for Biomedical Engineering. This commission found a need for about seven thousand bioengineers and biotechnicians in West Germany. It is shown, however, that there are actually very few positions open, and some measures to create more positions are discussed.

Biomedical Engineering↗
PubMed1977

[Short- and long-term prognosis of cardiac arrest in acute myocardial infarction (author's transl)].

Of 80 patients with acute myocardial infarction who had a cardiac arrest without shock 42 (52.5%) were resuscitated in a cardiological intensive care unit. Twenty-six were finally discharged from hospital. After an average of four years, 21 patients were still alive. Prognosis of primary ventricular fibrillation, the most frequent cause of circulatory arrest (51) was more favourable than that of primary asystole (23 patients). The younger the patient the better the prognosis: the average age of the 21 who survived for several years was 12 years less than those who had died. Follow-up examination indicated that 13 had signs of heart failure. Ventricular extrasystoles were demonstrated by ECG in 11. Eight had depressive episodes. It is likely that a further decrease in death-rate can be achieved only if the interval between onset of infarction and admission to an intensive care unit can be shortened.

Age Factors↗
PubMed1977

[Familial asymmetrical septal hypertrophy with and without obstruction: clinical findings in patients with echocardiographically confirmed diagnosis (author's transl)].

Obstructive and non-obstructive asymmetrical septal hypertrophy (ASH) is a relatively common disease which has no characteristic clinical symptoms. In only 14 of 71 patients in whom the diagnosis had been confirmed echocardiographically had it been possible to make the diagnosis by clinical means alone. Most of the patients had no specific clinical symptoms (angina, dyspnoea, systolic murmur, non-specific ECG changes) indicating a cardiomyopathy. Every patient with such uncharacteristic signs should therefore be studied by echocardiography in order to exclude ASH. In 17 patients there were no clinical symptoms at all, the diagnosis being made entirely by echocardiography.

Adolescent↗
PubMed1977

[Sodium nitroprusside in the treatment of left-sided heart failure in acute myocardial infarction (author's transl)].

27 patients (8 women, 19 men) aged 39-79 (mean 61) years with acute transmural mycoardial infarction and limitation of left ventricular function were treated in the acute stage for 24-72 (mean 55) hours with intravenous infusions of sodium nitroprusside in concentrations of 10-200 microng/min. Haemodynamic measurements before and 12 hours after onset of treatment showed a significant reduction in mean arterial pressure by 19%, in end-diastolic pressure in the pulmonary artery by 33% and in the total peripheral resistance by 32%, whereas stroke volume and cardiac index rose by 12% and 17%, respectively. The percentage improvement was most marked in those patients most severely affected. The mortality rate of cardiogenic shock was reduced to 25%. In a control group with haemodynamically similar left ventricular failure the mortality rate was 55%. However, the total mortality was nearly unchanged as the number of sudden unexpected deaths after the fourth day rose from 23 to 50%. Further investigations will show how these sudden deaths, mainly due to arrhythmias, can be prevented.

Adult↗
PubMed1977

Left ventricular hemodynamics and function in acute myocardial infarction: studies during the acute phase, convalescence and late recovery.

The left ventricular hemodynamics of 70 patients with acute myocardial infarction were determined from measurements of pulmonary arterial end-diastolic pressure, cardiac index, mean arterial pressure and heart rate during the acute phase(first study, 5 hours after admission), 4 to 6 weeks later (second study, during convalescence) and in 35 percent of all subjects 6 to 12 months after the acute infarction (third study). Serial analysis of serum creatine kinase was carried out during the acute phase. The peak CK value normalized for body surface area was used as a rough index of the extent of the acute myocardial necrosis. The condition of all survivors of the acute stage improved. Patients with only slightly reduced left ventricular performance during the acute stage recovered to nearly normal during convalescence. The condition of patients with greatly reduced left ventricular function also improved but remained impaired during convalescence. In all patients the main changes in left ventricular hemodynamics occurred within the first 4 to 6 weeks; there was almost no further alteration during the following 9 months.

Acute Disease↗
PubMed1977

Infarct size estimated from serial serum creatine phosphokinase in relation to left ventricular hemodynamics.

In 50 patients with proven acute myocardial infarction (AMI), left ventricular hemodynamics (pulmonary end-diastolic pressure [PAEDP]; cardiac index [CI]; stroke volume index [SVI]; and SVI/PAEDP were related to the size of the acute infarct. Acute infarct mass was calculated from serial determinations of serum creatine phosphokinase (CPK) every two hours, using a computer program. In 15 cases postmortem measurement of acute infarct size after staining with Nitro-BT was made and correlated with calculated infarct size. Correlation in this limited number of cases was good with a mean difference of 7 g. Acute infarct mass in 38 survivors was 46 +/- 5 g and was significantly smaller (P less than 0.05) than in the 12 nonsurvivors (76 +/- 12 g.) PAEDP in surviving patients was significantly lower (17 +/- 1 mm Hg) and SVI (36 ml/m2) and SVI/PAEDP (2.4 ml/m2/mm Hg) significantly higher than in the nonsurvivors (PAEDP: 24 mm Hg; SVI: 23 ml/m2; SVI/PAEDP: 0.86 ml/m2/mm Hg) (P less than 0.001 for all differences). Similar significant differences were observed between patients not in shock and those in cardiogenic shock. Although in 39 patients, in whom the infarction was their first, infarct mass was larger (58 +/- 6 g) than in 11 patients with repeat infarctions (37 +/- 8 g), left ventricular hemodynamics were slightly more impaired in reinfarctions (PAEDP: 21 +/- 3 mm Hg; CI:2.60 L/min/m2) than in first infarctions (PAEDP: 18 +/- 1 mm Hg; CI:2.82 L/min/m2). The occurrence of cardiogenic shock was a strong predictor of death; however, the wide scatter of the data for the parameters cardiac index, PAEDP, and acute acute infarct mass precluded their usefulness, when taken individually, in predicting survival. When a relationship between hemodynamics and infarct size was looked for, four constellations of individual patients were identified. These groups were defined by PAEDPs of above or below 18 mm Hg and infarct sizes above or below 65 g. Class A patients (N = 22) had a small infarct (29 +/- 4 g) and good pump function (PAEDP: 13 mm Hg; SVI: 40 ml/m2; SVI/PAEDP: 3.27 ml/m2/mm Hg); prognosis was good for these patients. In class B (N = 13) the infarct was large (96 +/- 8 g) and pump function markedly impaired (PAEDP: 26 mm Hg; SVI: 24 ml/m2; SVI/PAEDP: 0.98 ml/m2/mm Hg); 54% of these patients died. Five patients in class C had, in the presence of a large infarct (84 g), only a slightly elevated PAEDP of 17 mm Hg and an almost normal SVI of 37 ml/m2. In contrast, the ten class D patients had an infarct size (34 g) similar to that in class A, but high PAEDP (23 mm Hg) and moderately reduced SVI (31 ml/m2). In this group a high incidence of reinfarctions (six out of ten) occurred. It is concluded that infarct mass calculated from serial CPK analysis, as a single parameter, cannot be used to predict mortality or development of cardiogenic shock in an individual patient.

Acute Disease↗