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Biomedical subjects

K Amplatz

Publications and source records attributed to K Amplatz.

At least 307 records · Page 17Linked to original sources
PubMed1976

Comparison of ejection fraction calculated by nine different volume calculation methods.

Single plane right anterior oblinque ventriculography was performed on 25 patients with normal left ventricular contraction and on 25 with left ventricular akinesia or dyskinesia. The value of the left ventricular ejection fraction (EF) was calculated by 9 different methods, including a new one utilizing the mathematical model of a cone. All methods tested were appropriate for inter-group comparisons of EF. For inter-individual comparisons, however, only those methods described by Davila, Chapman, Dodge, Beranek, and our new method, are appropriate.

Angiocardiography↗
PubMed1976

A method to absorb scattered radiation without attenuation of the primary beam.

A method is presented for improving image quality by decreasing the scattered radiation. Two pairs of lead plates, one above and one below the patient, move in arcs with a common pivot point, the focal spot of the x-ray tube. The lower plates are separated by a 1-cm slot. The upper plates are also separated by a slot, the edges of which lie on common radii from the focal spot. The image is formed by moving the slots so that the X-ray beam emerging from the object sweeps across the film with a uniform speed during the exposure.

Humans↗
PubMed1976

The effect of valium on myocardial blood flow.

The effect of Valium on coronary blood flow was studied. In 18 patients undergoing coronary angiography, total and regional myocardial blood flow was determined by the 133Xe wash-out technique. A total of 39 pre- and 39 post-Valium injection wash-out curves were constructed. Results indicate (99% confidence) that intravenous Valium injection (0.1 mg/kg body weight) decreases myocardial blood flow 12--15%.

Angiography↗
PubMed1976

A device to measure roentgenographic structures.

A simple device and a nomogram are presented to permit rapid, accurate measurement of structures shown on roentgenograms. The arrangement is designed specifically for measurement of coronary vessels, but it can be adapted to other structures.

Angiography↗
PubMed1976

Hemodynamic assessment of obstructive aortoiliac disease.

Angiographic demonstration of obstructive aortoiliac disease is of paramount importance prior to surgery. Obstructive disease in the femoral popliteal system can only be surgically relieved if inflow is adequate. Severely stenotic lesions may be missed by angiography due to the oblique course of the iliac arteries and inability to obtain right angle views. Translumbar downstream catheterization of the abdominal aorta and puncture of both femoral arteries allows simultaneous pressure recordings. The injection of 30 mg of papaverine into the femoral artery assures maximal vasodilatation mimicking conditions under exercise. A minimal gradient at rest may become obvious following the injection of papaverine, indicating hemodynamically significant disease and warranting surgical correction. The technique has proved to be simple and valuable, and there have been no complications.

Aorta, Abdominal↗
PubMed1975

Regional Myocardial Blood Flow Measurement in the Evaluation of Patients with Coronary Artery Disease.

Myocardial imaging with 133-Xe and a gamma camera was employed to evaluate total and regional myocardial blood flow. The technique detected vasodilatation after injection of papaverine or diatrizoate. Contrast medium caused transient vasodilatation with return to baseline flow within five minutes. Myocardial tissue flow tended to decrease as coronary artery stenosis became more severe. There was overlap of flow measurements in patients with and without coronary artery disease. Coronary flow measurements made at rest are not considered to be an essential clinical tool. gpreater diagnostic benefit is obtained from the scintigram which distinguishes between akinesia caused by ischemia and akinesia due to extensive scarring.

Contrast Media↗
PubMed1975

Regional myocardial blood flow measurements before and after coronary bypass surgery. A preliminary report.

Myocardial blood flow in 16 patients before and after coronary bypass surgery in conjunction with coronary angiography, left ventricular function measurement, and graded exercise test. Radioactive 133-Xe was injected into the coronary artery or bypass graft and the washout was recorded by an Anger camera. Myocardial blood flow increased in 11 out of 14 patients and decreased in three patients. The average flow was 55 (plus or minus 6) preoperatively and 96 (plus or minus 10) ml 100 g/min postoperatively. Increase of blood flow occurred in both the bypassed left anterior descending coronary artery (LAD) region and the nonbypassed left circumflex coronary artery (LCIR) region. The postoperative flow increase and the absolute postoperative flow values are higher with saphenous vein than with mammary artery grafts. Statistically significant correlation is not found between myocardial blood flow changes and exerice tolerance. The volume measurements (end diastolic volume, stroke volume, ejection fraction) remained unchanged.

Adult↗
PubMed1975

Polyvinyl alcohol (Ivalon)--a new embolic material.

Successful nonsurgical treatment of gastrointestinal bleeding and arteriovenous malformations by embolization techniques has been previously documented. 1) Compressed Ivalon sponge was found to be a suitable embolic material in animals and in four patients. 2) The material has been extensively used in surgery, and its biocompatibility has been proved. 3) Expansion of the compressed sponge to its original size after embolization makes this material extremely effective. Recanalization did not occur in animals and humans. 4) For the occlusion of larger arteries, Ivalon can be wrapped around the guidewire. Ivalon sponge absorbs blood and serum, unwraps itself allowing withdrawal of the guidewire. 5) Embolization procedures are not without risk since reflux of embolic material may occur. Therefore, these procedures have to be carried out under fluoroscopic control.

Animals↗