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Biomedical subjects

H H Hilger

Publications and source records attributed to H H Hilger.

At least 73 records · Page 4Linked to original sources
PubMed1990

[A new Doppler echocardiography parameter of diastolic ventricular function].

The evaluation of flow velocities in left ventricular inflow tract (LVIT) by Doppler echocardiography gives information about the diastolic ventricular function. In late diastole, shortly after the flow velocity of atrial contraction V(A), we notice in the left ventricular outflow tract (LVOT) a laminar flow velocity directed to the aortic valve. The purpose of this study was to compare this flow velocity V(A*) in the LVOT with the flow velocity of the atrial contraction V(A), and the flow velocity of early diastole V(E) in LVIT, to determine whether such comparison would provide information concerning diastolic function. We studied three groups: 39 patients with left ventricular hypertrophy (HY) (mean age 56 +/- 12 y, 77% male), 41 patients with coronary heart disease (KHK) (mean age 53 +/- 10 y, 85% male) and 41 healthy subjects (N) (mean age 50 +/- 16 y, 51% male); all three groups were studied by pulsed Doppler from apical 4 chamber view in LVOT for maximal velocity (Vmax-A*) and time velocity integral of A* (TVI-A*), and in LVIT for maximal velocity of early diastole (Vmax-E), maximal velocity of atrial contraction (Vmax-A), ratio Vmax-E/Vmax-A, and the time velocity integrals (TVI-E, TVI-A). A slight correlation between Vmax-A* and Vmax-A was found (r = .60), being nearly the same as for TVI-A* and TVI-A (r = .64).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

[Control of the effectiveness of nitrate therapy with long-term ECG based on spontaneous ST segment changes].

In a population of 40 patients with coronary artery disease the overall incidence of spontaneous ischemic episodes during 24-h Holter monitoring could be significantly reduced with ISDN 120 mg ret. and ISDN 120 mg plus Diltiazem 120 mg ret. However, the intraindividual day-to-day variability of ischemic episodes on three consecutive days of Holter monitoring is taken into consideration, an intraindividual reduction of ischemic episodes of at least 97% is required to separate a true therapeutic effect from the considerable spontaneous variability.

Adult↗
PubMed1989

[Noninvasive assessment of aortocoronary bypass using magnetic resonance tomography].

Forty-four patients with recent cardiac catheterization because of recurrent chest pain after coronary artery bypass surgery were studied by magnetic resonance imaging to evaluate graft patency. To assess the efficacy of this non-invasive method 92 coronary artery bypass grafts were examined by the spin-echo technique. ECG-gated transversal sections were acquired between the diaphragm and the aortic arch. The specificity of magnetic resonance imaging was 83% (48/58) for patent grafts. However, the sensitivity in the detection of occluded bypasses was only 56% (19/34). Despite the good specificity, clinical applications of this method are limited because of its low sensitivity.

Coronary Artery Bypass↗
PubMed1989

[Mechanical recanalization of chronic coronary artery occlusion by balloon dilatation. Hemodynamic and ventricular kinetic long-term results].

Abundant collaterals may prevent infarction in a region of myocardium supplied by an acutely occluded coronary artery. However, these patients often present with severe angina on exertion which cannot be sufficiently treated with antianginal drugs but require revascularization. Beginning in 1984, recanalization of chronic coronary artery occlusion using balloon catheters was attempted in 48 patients at Medizinische Klinik III, University of Cologne. Interventional therapy was successful in 29/48 patients (60%). The mean diameter narrowing of residual stenoses was 35%. Invasive follow-up at 3 months was possible in 17 of these 29 patients. Restenosis was noted in 41% and reocclusion was found in 18%. In contrast to angiographic findings, clinical symptoms were clearly improved in the majority of cases (88%). This correlates with increased regional contractility of the myocardial region supplied by the previously occluded artery. Contractility was also improved in patients with significant restenosis. The clinical benefit and the improvement of regional myocardial function indicate that it is justified to attempt balloon recanalization in highly symptomatic patients with short distance coronary occlusions despite the relatively high incidence of restenosis and reocclusion.

Angioplasty, Balloon, Coronary↗
PubMed1989

[Clinical and magnetic resonance tomography follow-up of surgically treated aortic isthmus stenoses in adults].

Functional impairment and local pathological changes of the aorta especially at the site of correction are well known complications after surgery for coarctation of the aorta. To evaluate the longterm results after this operation, 23 patients were assessed by physical examination, EKG, ergometry, spirometry, and magnetic resonance imaging. The postsurgical interval ranged from 1 to 28 years. The most frequent postoperative symptoms were vertigo, headache, dyspnea on exertion, cardiac arrhythmia, and left thoracic pain. Elevation of the left shoulder was found in 19 patients to be due to left lateral thoracotomy; 14 patients suffered from arterial hypertension; five additional patients showed hypertension on exertion. Magnetic resonance imaging showed pathological changes of the aorta and aortic branches in all patients. The origin of the left subclavian artery was displaced distally in eight patients. The proximal part of the left subclavian artery was dilated in 11 patients. Fourteen patients had a hypoplastic aortic arch. An aneurysm of the ascending aorta was found in five patients. Aneurysmal dilatation of the descending aorta in the region of the anastomosis was present in three patients. Restenosis of the descending aorta occurred in two patients. In conclusion, after surgery of coarctation many patients continued to have symptoms which require regular follow-up. Magnetic resonance imaging provides a complete and noninvasive examination of the heart and the great vessels and is therefore ideally suited for this purpose.

Adolescent↗
PubMed1989

[The value of nuclear cardiology procedures including nuclear magnetic resonance tomography in routine diagnosis].

Nuclear-cardiological diagnostic methods require close cooperation between cardiology and nuclear medicine groups. This review article summarizes the advantages (non-invasive, quantitative, effect of exercise) and the disadvantages (limited resolution, limited specificity, radiation exposure) of the methods. Methods used routinely in the clinic are radionuclide ventriculography and myocardial scintigraphy with Tl-201. The indications for and limitations of these methods are discussed. The important advantages of nuclear magnetic resonance imaging (MRI) are the large field of view which includes extra cardiac structures, choice of slice width and orientation, good resolution and the simultaneous evaluation of morphology, functional parameters, flow phenomena and some differentiation between tissues. Presently, MRI is indicated in problem cases, e.g., aortic aneurysm, dissecting aneurysm, constrictive pericarditis, cardiac and paracardiac tumors. MRI also provides useful complementary information in valvular regurgitation, congenital malformations, cardiomyopathies and intracavitary thrombi. However, magnetic resonance imaging is still under development so that its overall value in the diagnosis of cardiac diseases cannot yet be definitely assessed.

Gated Blood-Pool Imaging↗
PubMed1989

[Possibilities and limits of quantitative image analysis using magnetic resonance procedures].

Magnetic resonance imaging provides three-dimensional images of the heart with good spatial and temporal resolution. Therefore, right and left ventricular function can be assessed without assumptions regarding ventricular morphology. Depiction of intracardiac blood flow with gradient echo sequences permits estimation of the severity of valvular regurgitation. Using improved paramagnetic contrast media magnetic resonance imaging may be able to directly visualize regions of ischemic myocardium. Real-time imaging of the heart will be possible using echo planar techniques. Although quantification of cardiac parameters by MRI is still mainly a research tool, clinical applications will emerge in the near future.

Heart Diseases↗
PubMed1989

[Non-invasive diagnosis of atrial septal defects and anomalous pulmonary venous return using magnetic resonance tomography].

The present study was to evaluate the diagnostic information that may be obtained in patients with atrial septal defect (ASD) and/or with anomalous pulmonary venous return using spin echo and gradient echo magnetic resonance imaging (MRI). The interatrial septum and pulmonary veins were studied in 31 patients and in 16 healthy volunteers. In all patients cardiac anatomy and dilatation due to right-sided volume overload was well depicted. In 87% of the patients examined by spin echo technique and in 100% of the patients examined by gradient echo technique the defect was reliably documented. All cases of anomalous pulmonary venous return were shown. MRI diagnosis of ASD was improved by combined use of spin echo and gradient echo techniques. The new MRI sequence was particularly helpful in patients with small ASDs and anomalous pulmonary venous return.

Adolescent↗
PubMed1988

[High-frequency angioplasty in coronary disease. Initial clinical experiences].

After extensive animal experiments a new method of high-frequency current coronary angioplasty (HFCA) via a specially developed catheter system was used in ten patients with haemodynamically significant coronary artery stenoses. In eight patients the stenoses affected the anterior interventricular branch (AIVB), in one patient each the circumflex branch and the right coronary artery, respectively. In nine patients the stenosis cross-section was reduced by at least 20% (from a mean of 91.9% +/- 5.8% to 52.6 +/- 17.5%). In three patients HFCA was followed by balloon angioplasty. The total number of applications per patient ranged from 3 to 12 (mean total duration of current flow: 3.9 +/- 1.0 s). There was only one severe complication, in a patient with subtotal AIVB occlusion after initially successful HFCA: balloon angioplasty successfully restored the lumen to the post-HFCA state. The new technique of HFCA is worthy of further development. It promises to be a valuable addition or alternative to balloon coronary angioplasty.

Adult↗
PubMed1988

The clinical significance of coronary angioscopy in patients with coronary heart disease.

The feasibility and safety of coronary endoscopy was evaluated in three sets of investigations: in 7 cadaver hearts, in 11 patients undergoing coronary bypass surgery, and in 30 patients during routine cardiac catheterization prior to coronary balloon angioplasty (PTCA). In three of the seven cadaver hearts the lumen of the arteries appeared normal. In three diffuse atherosclerotic lesions, and in one, a high-grade, tight stenosis were observed. In nine of eleven patients in the operation room, the lesions of interest could be visualized, and high-grade stenoses were found in all. In addition, in three patients with unstable angina pectoris, fresh thrombi were seen at the site of stenosis. In six of the nine patients, the periphery of the native coronary vessel was found to have no further stenotic regions. During cardiac catheterization in 17/30 patients, the lesion of interest could be examined angioscopically, and in 13 instances the stenosis appeared excentric and irregularly shaped. In three instances, multiple ulcerations were seen in the stenotic area. In two of the five patients, intimal ruptures were found following PTCA, which could not be documented angiographically. Coronary endoscopy provides valuable additional information on the nature and appearance of atherosclerotic lesions. It can be performed clinically without great harm to the patients. Despite some limitations, it will probably become a routine diagnostic tool in patients undergoing routine coronary angiography, balloon angioplasty or high-frequency angioplasty, and coronary bypass grafting.

Angioplasty, Balloon↗
PubMed1988

Cardiac function by magnetic resonance imaging.

Gated magnetic resonance imaging of the heart displays cardiac structures with excellent resolution. This ability should be useful for assessment of cardiac physiology where acquisition of systolic and diastolic images is required. In this study, left ventricular ejection fraction was determined in 50 patients from oblique long axis views of the left ventricle using the area length formula. Angulated views were obtained by electronic gradient angulation. For comparison, all patients had monoplane angiocardiography in the RAO position. Forty-five patients were also studied by radionuclide ventriculography. Ejection fractions determined by MRI and angiocardiography were closely correlated (r = 0.90). Correlation between MRI and radionuclide ventriculography was also acceptable (r = 0.79). In addition to global left ventricular function, MR images provide information about regional wall motion. In order to acquire a three-dimensional set of images at various phases of the cardiac cycle, shorter imaging times are mandatory. A new imaging technique with potential for functional studies uses low flip angles, short repetition times and gradient refocused echoes. Up to 40 images can be obtained within one cardiac cycle. When displayed in a looped fashion, visual assessment of cardiac motion, intracardiac blood flow, and systolic wall thickening is possible. Potential advantages of functional studies by MRI are the concomitant acquisition of anatomical information and the three dimensional frame of reference.

Angiocardiography↗