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Biomedical subjects

H Tillmanns

Publications and source records attributed to H Tillmanns.

At least 127 records · Page 7Linked to original sources
PubMed1977

[Heart diagnosis using m-mode-echography. Continuous registration of transverse left-ventricular internal diameters. IV. Patients with coronary artery disease (author's transl)].

"Relative Cross-sectional area Differences" (RCD) and "Relative mean Velocity of Contraction" (RVC) can precisely be determined by means of impulse-reflected ultrasound. They are highly invariant under physiological conditions and closely related to the degree of non-ischemic myocardial disorders. To evaluate the diagnostic information of these parameters in coronary artery disease (CAD), echocardiographic examinations were performed on 105 subjects. The results were compared with the angiocardiographically determined ejection fraction and with minimal cardiac transit times. The heart-dynamic data were grouped according to the manifestation of CAD and correlated to each other. Furthermore the parameter's capability in identifying differences in hemodynamics in normals and in patients with CAD was tested. In more than 90 per cent of patients with CAD, RCD and RVC exceeded the normal range. For clinical diagnosis the results lead to certain limitations in the validity of the echocardiographic parameters. In cases of infarction localized at the apex and in myocardial aneurysmas, RCD and RVC reflect the function of the whole myocardium, not the ejection fraction of the left ventricle. In those cases of infarction of the posterior or posterolateral wall, the value of RCD and RVC could not be verified. If infarction occurs at other localizations (septum, anterior wall), RCD and RVC show the degree of reduced myocardial function without any limitation.

Adult↗
PubMed1976

[Heart diagnostics using M-mode echography. Continuing registration of transverse internal left ventricular diameters. II. Determination in patients with myocardial insufficiency with special reference to ischemic heart disease].

Relative Cross-sectional area Differences (RCD) and Relative mean Velocity of Contraction (RVC) are easily, quickly and precisely determined by means of impulse-reflected ultrasound. They were recognized to be highly invariant under physiological conditions and thus were considered as sensitively regulated heart-dynamic-parameters. (his paper reports about a total of 395 examinations on patients with myocardial disease and on normal subjects. Various pathogenic factors are included excepting patients with myocardial infarction. In all subgroups there is a decrease of RCD and RVC with increasing degrees of cardiac disease. Correlating the angiocardiographically determined left-ventricular ejection fraction with both parameters, they show a significant linear relationship. Even in clinically latent myocardial disease the echocardiographic parameters are defnitely reduced. Small changes of myocardial function, e.g. under digoxin and in different degrees of uremic heart disease with uremic cardiomyopathy, can be recognized by RCD and RVC under exclusion of extracardiac factors. Physical tests during exercise confirm the observed trends. The typical changes of the echocardiographic parameters in myocardial disease, permitting a sharp discrimination of pathologic values with their small physiological variability, identify RCD and RVC as sensitive parameters of the mechanical function of the myocardium in the range of validity that was examined. The described properties and the lack of discomfort to the patient suggest a number of important indications of this method.

Cardiomyopathies↗
PubMed1975

Lipid metabolism in perfused human and dog coronary arteries.

The paper represents a summary of our studies in which in vitro perfusion of human and animal coronary vessels was carried out. Formation and uptake of lipids in perfused human coronary arteries were studied under a vairety of experimental conditions, including exposure to carbon monoxide. The effect of collagenase on lipid synthesis and transport in carotid arteries of dogs was also studied. Human plasma with hydrogen-3-labeled cholesterol and carbon-14-acetate was used to perfuse human blood vessels. Autologous plasma was employed. Inhibition of cholesterol uptake was accomplished by the addition of 7-ketocholesterol (concentrations of 0.005 to 1 mum/ml) to the perfusate. Both atherosclerotic and normal human coronary arteries incorporated 14C-acetate into lipids but failed to synthesize either cholesterol of cholesterol esters. Similar results were obtained in human saphenous veins perfused at arterial pressure. Cholesterol uptake from the perfusion fluid was demonstrated in atherosclerotic and normal human coronary arteries as well as in human saphenous veins. Carbon monoxide increased permeability of the arterial wall to cholesterol uptake. In dog arteries exposed to collagenase marked increases in cholesterol uptake were found, but total lipid synthesis was reduced; the relative synthesis individual lipids remained unchanged. The addition of 7-ketocholesterol to the perfusate reduced cholesterol uptake by the vessel by 90 percent. Inhibition of cholesterol uptake was present in all species and was not due to oxidation of cholesterol to 7-detocholesterol in the perfusate. The results illustrate that human coronary arteries as well as human saphenous veins synthesize lipids but not cholesterol. Cholesterol flux into the artery is augmented by carbon monoxide and collagenase. The data also show that active inhibition of cholesterol uptake in the arterial wall can be accomplished by competitive inhibition with 7-ketocholesterol.

Acetates↗
PubMed1975

Blood flow velocity in the carotid artery as a measure of myocardial contractility.

An attempt was made to derive a useful noninvasive index to evalute a change in myocardial contractile state using transcutaneous Doppler flow-velocity curve from the carotid artery. In 5 mongrel dogs and in 43 patients with various heart disease, Doppler flow velocity curves were obtained from the ascending aorta intravascularly using a Doppler catheter and/or from carotid artery transcutaneously using a Doppler probe. The first derivative of left ventricular pressure (dp/dt) and electrocardiogram (ECG) were recorded simultaneously. The following 3 indices were measured from the Doppler flow-velocity curves: (1) macimum acceleration of blood flow (dv/dt), (2) time from onset of ejection to peak flow (time-to-peak), (3) time interval between the beginning of Q wave of ECG to the peak of Doppler flow velocity curve (ECG Q-Doppler peak). Among these 3 indices, only ECG Q-Doppler peak demonstrated a significant correlation between the values measured intravascularly and transcutaneously. Also, only ECG Q-Doppler peak showed significant correlation with maximum of dp/dt (max dp/dt). Since ECG Q-Doppler peak showed correlation with heart rate, the difference between observed and predicted ECG Q-Doppler peak (delta ECG Q-Doppler peak) was calculated to exclude the effect of heart rate. Predicted value of ECG Q-Doppler peak was calculated from the regression equation between heart rate and ECG Q-Doppler peak in the separate experiments. There was significant correlation between delta ECG Q-Doppler peak and max dp/dt. In 15 patients with coronary artery disease and in 16 healthy subjects, delta ECG Q-Doppler peak and the other noninvasive method (systolic time intervals) were measured. Delta ECG Q-Doppler peak showed better result in the separation of 2 groups than by systolic timeintervals. It was concluded that delta ECG Q-Doppler peak is a useful index to evaluate the myocardial contractile state since this index is readily obtained noninvasively.

Adolescent↗
PubMed1975

Radioisotopic measurements of coronary blood flow.

This review has presented a critical evaluation of current methods used in measurement of total and regional blood flow. Measurement of total coronary blood flow furnishes little evidence of pathological processes within the coronary vascular system. However, in conjunction with coronary vasodilators, measurement of total coronary blood flow may indicate the presence of coronary artery disease. Difficulties inherent in the determination of regional coronary blood flow lie primarily in defining clearance slopes and in the presence of accidental counts. More promising are methods using scintigraphs obtained with radioactive particles injected into the coronary artery. However, these procedures do not measure flow, only flow distribution. A procedure for measuring regional uptake of positron emitters by coincidence counting has been described; the method possesses definite advantages over other procedures, since it is noninvasive and appears to have good resolution. However, the method is dependent on higher decay density which necessitates the use of nuclides with a short half-life (e.g., 81rubidium).

Animals↗
PubMed1975

Coincidence and noncoincidence counting (81Rb and 43K): a comparative study.

This paper compares the accuracy of imaging and resolution obtained with 81Rb and 43K using coincidence and noncoincidence counting. Phantoms and isolated infarcted dog hearts were used. The results clearly show the superiority of coincidence counting with a resolution of 0.5 cm. Noncoincidence counting failed to reveal even sizable defects in the radioactive source.

Animals↗
PubMed1973

The effect of prolonged administration of ethanol on cardiac metabolism and performance in the dog.

The effect of prolonged administration of alcohol on mitochondrial function and high-energy phosphate (ATP) of heart muscle was investigated in dogs. Animals were divided into two groups, a control group and a group that received alcohol. In the experimental series, dogs received 400 ml of a 25% solution of alcohol added to the food and drinking water. Measurements were carried out after ethanol had been withheld for 2 days. Total myocardial blood flow, cardiac output, and myocardial O(2) consumption remained at control levels. Measurement of cardiac contractility using the maximal rate of left ventricular pressure rise (dP/dt(max)) showed no change in animals exposed to alcohol. When the afterload of the heart was increased with angiotensin, a slight but not significant decline in cardiac contractility was observed. Activities of various intramitochondrial and extramitochondrial enzymes were measured in both groups. After alcohol administration, the primarily intramitochondrial isocitrate dehydrogenase diminished. ATP in heart muscle of dogs exposed to alcohol declined, and mitochondrial oxygen consumption and respiratory control indices diminished. These observations suggest that the primary lesion leading to alteration of myocardial performance is a biochemical malfunction of the mitochondria, which at this early stage is not reflected in changes in myocardial contractility.

Adenosine Triphosphate↗