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Biomedical subjects

I Hulín

Publications and source records attributed to I Hulín.

At least 37 records · Page 2Linked to original sources
PubMed1994

Segmental blood flow through intramyocardial coronary arteries during ventricular systole.

The presented hypothesis assumes, in contrast with the currently prevailing view, that blood continues to flow through the coronary vascular bed even during systole. The contraction of differently oriented myocardial layers closes the penetrating branches of the coronary arteries in the interlayer boundaries. Coronary arteries of a different caliber are during systole under equal intramyocardial pressure. In accordance with the theory of elasticity, the action of an equal external pressure decreases with the lumen of the vessel and, thus, the net effect of these forces will push the blood into smaller vessels within the segment in the layer. This hydrodynamic effect empties the larger coronary arteries during systole so that they are ready for the subsequent massive influx of blood during diastole. The possible applications of this hypothesis in various physiological and pathological conditions are compatible with the present knowledge and might contribute to a more precise understanding of implicated pathophysiological mechanisms.

Blood Flow Velocity↗
PubMed1994

Gliding-window fast Fourier transform analysis of the entire QRS complex and the distribution of area ratio peaks in healthy subjects and patients with myocardial infarction.

BACKGROUND: The high-frequency contribution (i.e. 60-120 Hz) within the QRS complex of the surface ECG is supposed to be related to the arrhythmogenic substrate underlying sustained ventricular tachycardia in patients with coronary artery disease. One of the factors that prevents a wider clinical application of spectral analysis based on the fast Fourier transform is the considerable intra-individual variability of its results. This study presents a novel alternative approach of frequency-domain analysis, aimed at minimizing this methodological drawback. METHODS: The proposed method uses gliding-window fast Fourier transform analysis of the signal-averaged ECG to provide values expressing the area ratio for two predefined frequency ranges (60-120 Hz divided by 0-120 Hz). The term gliding window is derived from the methodological principle by which the window analyzed is moved from the onset of the QRS complex into the ST segment. Values of area ratios obtained for every time instant of the interval of gliding are the basis for construction of curves. These are further analyzed in order to find patterns that characterize abnormal ventricular activation, with special emphasis on the identification of arrhythmogenic correlates. RESULTS: In a group of 30 healthy subjects, the distribution of area ratio peaks was characterized according to their value and timing. The distribution of area ratio peaks in 43 patients with myocardial infarction differed substantially from the normal distribution in the control group. The amplitude of the peaks and their timing was not related to the occurrence of late ventricular potentials. CONCLUSION: The method of gliding-window fast Fourier transform analysis eliminates the variability of results obtained by traditional spectral analysis of the ECG signal. A higher number and a different distribution of high-frequency peaks during the QRS complex in postmyocardial infarction patients reflect abnormal ventricular activation. However, late ventricular potentials are not related to a higher proportion of high frequencies in the corresponding time interval within the terminal QRS complex.

Adult↗
PubMed1994

The antihypertensive treatment and high-resolution electrocardiography.

After six months of antihypertensive treatment the regression of the initially present myocardial hypertrophy was observed: The decrease in blood pressure values is in correlation with the regression of the left ventricular hypertrophy. No correlation with parameters of high-resolution electrocardiography was noted. In one patient, a deterioration of late potentials was observed. It became more pronounced following the treatment. The monitoring of antihypertensive treatment effects by echocardiography and high-resolution electrocardiography may be therefore considered useful, especially in expected regression of the left ventricular hypertrophy. In individual cases of very outstanding regression, there exists the potential possibility of the process, resulting in the risk of arrhythmogenic substrate formation and subsequent generation of dysrhythmias.

Electrocardiography↗
PubMed1994

[Pathogenesis, prevention and detection of cardiotoxicity of anthracycline cytostatic agents].

BACKGROUND: Anthracycline antibiotics represent a part of therapeutic schemes in the treatment of a wide spectrum of malignancies. Precisely due to their cytostatic effectiveness they are being applied in spite of the risk of cardiac damage of patients. Anthracycline cardiotoxicity may culminate in potentially irreversible heart failure and fatal arrhythmias. Consequences of cardiotoxicity can complicate and shorten the lives of patients with formerly favourable prognosis of the malignant disease, and even of those that have been cured. OBJECTIVES: The aim of the presented study was to provide a review on current opinions concerning the pathophysiological mechanisms of cardiotoxicity due to anthracycline antibiotics, as well as the possibilities of cardiotoxicity prevention and detection. The procedure of cardiac monitoring of anthracycline effects is performed in order to detect the initial stage of myocardial impairment which is on the level of microstructural alterations. This requirement is mostly fulfilled by the invasive method of endomyocardial biopsy. Also the noninvasive method of high-resolution electrocardiography may reflect anatomic-electrophysiological abnormalities on the level of cardiomyocytes and interstitium. We decided to verify the usefulness of this method in the sense of the ability to detect the risk of the cardiotoxicity origin following anthracycline application. METHODS: We have repeatedly observed 34 hospitalized patients with cancer before or during chemotherapy. On the basis of high-resolution electrocardiography we have analysed the ECG signal in regard to time, frequency and time-frequency relation. RESULTS: In this study we present our initial experience with this method in combination with electrocardiographic and echocardiographic findings. In regard to the fact that the observations were of short term character we interpret our results of high-resolution electrocardiography as being preliminary. We report 4 illustrative cases of patients who independent of the dosage, yielded distinct responses toward the applied potentially cardiotoxic therapy. CONCLUSIONS: We consider the high-resolution electrocardiography in regard to its noninvasive character and low demand of time and finance to represent a perspective method of cardiac monitoring of the negative anthracycline effect. Not only ours but also the first experience in the world confirm this presupposition. By means of this method we have been able to detect initial alterations due to already low cumulative doses of anthracyclines (120 mg/m2 in a patient with ischemic heart disease and 260 mg/m2 in a patient with unimpaired myocardium prior to treatment). Our results also confirm the fact that the problem of cardiotoxicity must be necessarily strictly individualized. (Fig. 19, Ref. 80.)

Antibiotics, Antineoplastic↗
PubMed1994

[Hernias in the abdominal wall].

The authors emphasize the relapse frequency of the front abdominal wall hernias. Umbilical hernias, epigastric hernias, hernias in postoperative scars, as well as diastases of m. rectus abdominis are still not appropriately evaluated problem in surgery. Numeral surgical methods and procedures provide evidence of this fact. In spite of this, the relapses are frequent. In order to prevent relapses of hernias and to support the firmness of the abdominal wall, the authors use the corium graft technique. This study provides the description of the graft preparation. This surgical method was used in 54 patients, in whom no recurrence was recorded within the period of 1-3 years after surgery. The authors consider this procedure as being useful and effective. The methodical procedure is simple and economically advantageous, as autografts are ideal from the biological point of view. (Tab. 1, Fig. 6, Ref. 10.)

Female↗
PubMed1993

Body surface isochrone maps of peak R in normal adolescent girls.

The aim of our study was to evaluate the adequacy of a new mapping device for obtaining a reliable set of normal maps characteristic for this approach. We studied body surface isochrone maps of peak R in four healthy adolescent girls using the mapping system CARDIAG 128.1 with 80 unipolar leads placed in a regular grid. The constructed maps were compared with published data using 10 criteria. None of the maps obtained could be regarded as normal. After evaluating the reasons for the "abnormality", we assume that they could be caused mostly by the processing of signals. This fact can be eliminated by improving the existing software.

Adolescent↗
PubMed1989

Graphic representation of deviations of the cardiac electric field.

The first part of the paper presents a survey of mapping methods in electrocardiography and discusses the present possibilities of graphic representation of individual types of maps of the cardiac electric field (CEF). In the second part of the paper, the authors describe their own method of constructing complete departure maps. The mode of determining the matrix of the departure map surface is given. Four spatial maps--CEF surface, projection of CEF surface, threedimensional departure map, contour departure map--yield in one graphic output the complete departure map. The value of personal computers for diagnostic methods in medicine is being emphasized. The paper is supplemented by graphic outputs performed on the computer EC 1045 and represented by the plotter DIGIGRAF.

Computer Graphics↗
PubMed1989

[The abstract--why and how it should be written].

The aim of the study is to provide stimuli for writing concise and coherent abstracts imaging the original article without loss of critical substance and clarity. The main functions of abstracts in providing quick information and reliable sources for indexing are emphasized. The purposes of the prospective reader have to be considered as they should determine the form and content of the abstract. The two main types, i.e. indicative and informative abstracts are assessed. The indicative abstract states what the full paper is about and is thus suitable only for review papers, essays, and nonexperimental studies. As its primary purpose is to help decide whether the full article should be read, it is practically useless when it accompanies a paper written in a different and not commonly accessible language (e.g. Slovak article, English abstract). The informative abstract has a high load of specified information. When concerning experimental work, it should state the aim, the material or subjects involved and methods used, the results obtained, and the conclusions drawn. The recently introduced structured abstract for clinical papers presents a comprehensive image of the full article in a format that makes explicit the elements of critical argument. A framework of useful steps for writing abstracts is provided by analyzing the three main phases of the abstracting process, i.e. 1. analytic reading, 2. extraction, organization and reduction of information, and 3. critical editing. The presented summary of hints for writing reader oriented abstracts and the list of actual examples of obfuscation should increase the awareness and commitment of authors in preparing good-quality abstracts.

Abstracting and Indexing↗