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Biomedical subjects

I Hulín

Publications and source records attributed to I Hulín.

At least 19 recordsLinked to original sources
PubMed2005

Long-term monitoring of the changes in signal-averaged ECG after coronary artery occlusion and intracoronary endothelin-1 injection in dogs.

Myocardium undergoes functional changes in the infarcted region primarily due to ischemia. Following myocyte functional alterations of the noninfarcted myocardium are caused by remodelling and hypertrophy. We have monitored and compared changes in the electrocardiographical (ECG) image after coronary artery occlusion (CAO, n=5) and intracoronary endothelin-1 (ET-1, n=3) administration during a 6-month period. In 3 dogs, the CAO was repeated 6 months after the first occlusion. Signal-averaged ECG (SA ECG) was recorded before the operation and 10 days, 1 month, 3 months and 6 months after myocardial infarction (MI). The modified Wigner distribution was used for spectrotemporal analysis of the SA ECG. Eight-hour Holter monitoring was performed in each dog before and after experimental MI. Spectrotemporal representations of the QRS complex were stabilized after the first 1-month period in the group of dogs after CAO. The same results were also observed after the repeated CAO. No arrhythmias were recorded 9 days after CAO. The spectrotemporal representations of the QRS complex after intracoronary ET-1 administration were not stabilized during the whole observed period. Very few arrhythmic events were recorded by Holter monitoring already 3 days after intracoronary ET-1 injection. Experimental MI induced by CAO caused a changed ECG image, which was stable from 1 month after MI induction till the end of the monitoring. However, the ECG image after ET-1 administration was not stable during the whole observed period. No arrhythmic events were recorded in either group 3 months postoperatively that could be caused by healthy myocardial status before the experimental MI induction. In clinical practice, however, ischemic heart disease usually precedes the MI. Arrhythmogenic substrate could thus be a consequence of combination of healthy status of the myocardium before MI and MI itself.

Animals↗
PubMed2005

High resolution electrocardiography in healthy dogs: time domain parameters and comparison of the non-stationary (Wigner distribution) versus standard stationary frequency domain analysis methods.

Fractionated heart activation can be detected as late potentials from surface recordings of signal-averaged electrocardiograms (SA ECG) which are considered as a marker of sustained ventricular tachycardia. For animal studies, reference values in time and frequency domain analyses are essentially missing. In the present study, we have established reference values in SA ECG time domain analysis and time-frequency representation of heart activation in healthy dogs. A group of 25 healthy mongrel dogs (body weight 12-15 kg) was investigated. Wigner distribution and our modification of Fast Fourier transform (FFT), gliding window FFT, was applied in SA ECG frequency domain analysis. Reference values in time domain SA ECG were established. Time and voltage criteria were adapted to short duration of heart cycle and fast voltage decrement of the QRS complex in dogs. Wigner distribution and gliding window FFT were applied in order to describe mean heart activation in the frequency domain. Contribution of higher frequencies (30-80 Hz) was detected by both frequency analysis methods in the second third of ventricular activation in healthy animals. Presented results could offer a basis for further experimental arrhythmologic studies.

Algorithms↗
PubMed2003

The pacemaker activity of interstitial cells of Cajal and gastric electrical activity.

Interstitial cells of Cajal (ICC) are the pacemaker cells in the gut. They have special properties that make them unique in their ability to generate and propagate slow waves in gastrointestinal muscles. The electrical slow wave activity determines the characteristic frequency of phasic contractions of the stomach, intestine and colon. Slow waves also determine the direction and velocity of propagation of peristaltic activity, in concert with the enteric nervous system. Characterization of receptors and ion channels in the ICC membrane is under way, and manipulation of slow wave activity markedly alters the movement of contents through the gut. Gastric myoelectrical slow wave activity produced by pacemaker cells (ICC) can be reflected by electrogastrography (EGG). Electrogastrography is a perspective non-invasive method that can detect gastric dysrhythmias associated with symptoms of nausea or delayed gastric emptying.

Animals↗
PubMed2002

Restoration of upper extremity function after peripheral nerve injuries.

These days injuries to the peripheral nerves of the upper extremity that necessitate total or partial lesion are very common in the household and working environment. With regard to the majority of these injuries, not only plastic surgeons or neurosurgeons must have knowledge of their correct treatment, but general surgeons as well. The principles of reconstruction of the peripheral nerves of the upper extremity are described. The authors refer to immediate and delayed nerve repair, free nerve grafting, free vascularised nerve grafting, tendon transfer for a paralyzed hand, pedicled muscle transfer, functioning free muscle transplantation and neurotization.

Arm↗
PubMed2002

[The significance of aldosterone in chronic heart failure: the RALES study].

Reduction of excessive neurohumoral activation in chronic heart failure (CHF) improves the prognoses. In addition to reduction of angiotensin production or angiotensin II action and the influence of the sympathoadrenal system also blocking of aldosterone effects becomes part of the therapeutic procedure in patients with CHF. Excessive systemic and probably also local aldosterone production promotes undesirable fluid retention, hypokalaemia and hypomagnesaemia, induction of hypertrophy and fibrosis of the heart muscle and blood vessels and the development of endothelial dysfunction, peripheral vasoconstriction and depression of the baroreflex. In addition to classical effects also the existence of a rapid, so-called non-genomic effect of aldosterone is assumed. Adding a blocker of aldosterone receptors to ACE inhibition was not recommended due to possibility development of hyperkalaemia. Later it was revealed that ACE inhibitors are unable to block sufficiently the action of aldosterone and that addition of spironolactone in small amounts to ACE inhibition and diuretics does not cause in patients with CHF a major increase of the potassium level. In the RALES study (Randomized Aldacton Evaluation Study) comprising 1663 patients with serious heart failure (NYHA III, IV) addition of 25 mg spironolactone to standard treatment with ACE inhibitor, diuretic and as rule also digoxin reduced the mortality by another 30% as compared with the addition of placebo. Undesirable effects were minimal. As to potential protective mechanisms of spironolactone the greatest importance is ascribed to the reduction of excessive fibrosis of the heart muscle. Spironolactone reduces the level of the circulating N-terminal aminopeptide procollagen type III the high level of which is associated with deterioration of the prognosis.

Aldosterone↗
PubMed2001

Signal-averaged electrocardiography in survivors of Hodgkin's disease treated with and without dexrazoxane.

Doxorubicin is one of the most effective anticancer drug, but its usefulness is limited by the risk of developing cardiomyopathy, cardiac dysfunction and ventricular arrhythmias. Dexrazoxane is used to protect against doxorubicin cardiotoxicity. It is uncertain whether the dexrazoxane-mediated cardioprotective effect will be reflected in electrophysiological properties of the heart. The aim of the present study was to evaluate the occurrence of frequency-domain signal-averaged electrocardiographic (SAECG) abnormalities of the QRS complex and the initial ST segment in patients treated with and without dexrazoxane. Thirty children and young adults 2 months - 15 years after completion of doxorubicin-containing therapy for Hodgkin's disease were evaluated with SAECG. Patients from group I (n = 13) received combined therapy with doxorubicin and dexrazoxane (DOX/DZX), patients from group II (n = 17) received doxorubicin without dexrazoxane (DOX). Using fast Fourier transformation within the QRS complex and the initial ST segment, area ratio (AR) values 40-100/0-40 Hz were calculated. Significant differences in these frequency parameters in the QRS complex between DOX/DZX group and DOX group (19.45+/-12.72 vs 46.18+/-43.06; p = 0.03) might indicate protective effect of dexrazoxane on electrophysiological myocardial properties.

Adolescent↗
PubMed1998

[Vascular endothelium as a factor in information transfer between the cardiovascular and immune systems].

In health, the vascular endothelium forms a multifunctional interface between the circulating blood and various tissues and organs of the body. It constitutes a selectively permeable barrier for macromolecules, as well as a nonthrombogenic and nonadhesive container that actively maintains the fluidity of blood. It is a metabolically active endocrine organ, serving as the source of multiple factors and mediators that are critical for normal homeostasis. These include vasodilators (nitric oxide, prostacyclin, endothelium-derived hyperpolarizing factor), vasoconstrictors (endothelin-1, thromboxane A2, prostaglandin H2 and components of the renin angiotensin system), various pro- and antithrombotic factors (e.g. tissue factor, platelet activating factor--PAF, von Willebrand factor), fibrinolytic activators and inhibitors (e.g. tissue plasminogen activator, plasminogen activator inhibitor-1), potent arachidonate metabolites (prostanoids), leukocyte adhesion molecules (e.g. E-selectin, P-selectin, intercellular adhesion molecule-1--ICAM-1, vascular cell adhesion molecule-1--VCAM-1), and multiple cytokines with activities of growth stimulators and inhibitors, transforming growth factors, proinflammatory and antiinflammatory mediators, tumour necrosis factors and chemotactic factors (chemokines). Besides these essential activities controlling the cardiovascular system, the endothelial cells represent an important part of the immune system as well. They have a pivotal role in the initiation and development of defensive and damaging inflammatory responses. Therefore endothelium can be considered as being the central equipment for the mutual exchange of life important information between the cardiovascular and immune systems. This in turn is leading to rapid advances in understanding the pathogenesis of some of the most serious and most common diseases, including inflammation, atherosclerosis and hypertension. (Tab. 7, Ref. 89.)

Animals↗
PubMed1998

Signal-averaged ECG in patients after anthracycline therapy for childhood cancer.

Late cardiac complications after anthracycline therapy is an increasingly common problem among survivors of childhood cancer. Routine clinical examination may be normal, but subclinical cardiac abnormalities, which may progress with time, are documented in high percentage of these patients. Microstructural myocardial alterations may result in production of micropotential level signals (late potentials, LP) and altered frequency components of signal-averaged ECGs (SAECG). SAECG abnormalities are valuable in risk stratification of patients with various heart diseases culminating in fatal arrhythmias or heart failure. Forty-five pediatric oncologic patients (mean age 14.4 +/- 4.1 years) were included in the study. SAECG was performed 3 months-12 years (median 5.5 years) following completion of anthracycline therapy. The total cumulative doses of anthracyclines were 90-555 (median 230) mg/m2. The control group consisted of 30 healthy age-matched volunteers. LP were present in six (13.3%) patients after anthracycline therapy at 40 Hz high-pass filter setting. Using frequency-domain analysis within the QRS complex, area ratio 1 (area of 20 to 50 Hz/area of 0 to 20 Hz) and area ratio 2 (area of 40 to 100 Hz/area of 0 to 40 Hz) were calculated. Twenty (44.4%) and fourteen (31.1%) had abnormal values in area ratios 1 and 2, respectively, within the QRS complex. Area ratios 1 and 2 of patients after anthracycline therapy were significantly higher than those in control group (p = 0.0187 and p = 0.0043). Our preliminary results suggest that chemotherapy with anthracyclines, even in low dosage, is associated with increased incidence of SAECG abnormalities. The potential of this simple, noninvasive method to detect subclinical anthracycline-induced myocardial alterations and facilitate prognostic stratification of cancer survivors is promising, however, the clinical value of SAECG remains to be established in a larger and a longer study.

Adolescent↗
PubMed1997

Effect of captopril on the development of left ventricular hypertrophy in rabbits with aortic insufficiency.

We investigated the effect of captopril on the growth of the left ventricle in an experimental model of aortic insufficiency. Four groups of rabbits were studied 28 days after experimental intervention: 1. control, 2. control with captopril (10 mg/kg/day), 3. aortic insufficiency, 4. aortic insufficiency with captopril (10 mg/kg/day). Aortic insufficiency induced hypertrophic growth of the left ventricle demonstrated by increased weight and ribonucleic acid (RNA) concentration. Administration of captopril only slightly attenuated the weight increase of the left ventricle and the increase in concentration of left ventricular RNA. However, captopril reduced the concentration of left ventricular deoxyribonucleic acid (DNA) both in the control and even more in the group with aortic insufficiency. The chronic haemodynamic overload enhanced mitochondrial respiration in the left ventricle which was not influenced by captopril. We conclude that captopril in the dose 10 mg/kg/day did not prevent hypertrophy of the left ventricle but reduced left ventricular DNA concentration.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1996

[Can permanent sinus arrhythmia in conscious dogs be suppressed with anesthesia?].

OBJECTIVE: Large prospective studies in dogs with healed myocardial infarction (MI) recently show a positive relation between heart rate variability (HRV) and sudden cardiac death. METHODS: We have done similar experiments in dogs and we studied HRV, ECG and body surface potential maps (BSPM) in 26 normal mongrel dogs (10-15 kg) and 12 dogs with an experimental MI (ligation of LAD). A two-channel 8 hours lasting ECG recording was performed in all conscious dogs. The 2nd recording was done in Penthobarbital anaesthesia (30 mg/kg). RESULTS: We have found sinus arrhythmia (SA) in all 26 conscious dogs. The anaesthesia suppressed the sinus arrhythmia and HRV via compensatory tachycardia and alterations in baroreflexes. The suppression of arrhythmia was also present in dogs with myocardial infarction. CONCLUSIONS: It is suggested, that HRV and SA in dogs depend on conscious state and anaesthesia. On the basis of our results we can anticipate that the most important for HRV is the present status of the sympathetic nerve. We suggest, that our results are an important finding for experimental arrhythmology. (Fig. 4, Ref. 24.)

Anesthesia↗
PubMed1996

[High-resolution electrocardiography in monitoring myocardial damage after therapy with anthracyclines in children].

BACKGROUND: Anthracycline cytostatics, widely used in oncologic practice, may induce discrete myocardial damage occasionally culminating in life-threatening cardiologic complications. The most serious clinical manifestations of anthracycline cardiotoxicity are dilated cardiomyopathy, heart failure and fatal arrhythmias. OBJECTIVES, STARTING POINT AND MAIN PURPOSE: High-resolution electrocardiography (HRECG) is one of the latest cardiologic methods, which can be promising for early identification of patients at risk of anthracycline cardiotoxicity. The aim of this study is the evaluation of the incidence of HRECG abnormalities in a group of paediatric patients treated with anthracyclines and the usefulness of HRECG for stratification of patients at risk of the clinical cardiotoxicity. PATIENTS AND METHODS: A set of 60 oncologic paediatric patients treated with anthracyclines was divided into two groups. The first group was formed by 15 patients undergoing evaluation during their anthracycline therapy (median after the last administration of antracyclines was 3.2 days). Their average age at the time of examination was 14.7 +/- 4.1 years. The total cumulative dose of antracyclines was 40-300 mg/m2 (median 150 mg/m2). The second group was formed by 45 patients who were evaluated after completing anthracycline therapy. The interval of time from the last administration of antracycline in this subgroup of patients was 3 months-12 years (median 5.5 years). Their average age at the time of HRECG examination was 14 +/- 4.1 years. The total cumulative dose of anthracyclines was 90-440 mg/m2 (median 230 mg/m2). Six patients of this group (13.3%) were treated also with mediastinal radiotherapy (18-40 Gy). 43 patients (95.5%) of second group were in complete remission, two other patients yielded a progression of their malignancy. 10 patients (22%) were examined by HRECG 2-5 times in app. two-month intervals. The control group was formed by 30 randomly selected healthy children and adolescents with normal ECG. Average age was 15.1 +/- 5.8 years. Using HRECG the time- and frequency-domain characteristics of the ECG signal were analyzed. The time-domain analysis was performed at 40-250 Hz filter. The frequency-domain analysis was performed by fast Fourier transformation (FFT), a 120 ms segment starting 20 ms before the end of the QRS complex was analyzed. The altered frequency content was expressed as the ratio of frequency areas (area ratio, AR) 20-50 Hz/0-20Hz. The average level of noise was 0.56 microV in the first group, 0.62 microV in the second group of patients and 0.68 microV in the control group. RESULTS: Abnormalities in the time-domain analysis (ventricular late potentials, VLP) were present in 2 (13.3%) of 15 patients during the anthracycline therapy in the first group and in 4 (8.8%) of 45 patients after completing therapy in the second group. No abnormalities in the time-domain analysis were detected in the control group. Using frequency-domain analysis, abnormalities in AR20-50 Hz/0-20 Hz were found in 8 (53.3%) of 15 patients of the first group, and in 11 (24.4%) of 45 patients of the second group. Significant differences were observed in the frequency parameters of the ECG signal in patients of the first group in comparison to the control group (p = 0.0018) and also when comparing the patients of the second group and the control group (p = 0.045). CONCLUSION: The HRECG results in time- and frequency-domain analyses indicate to high incidence of HRECG abnormalities in patients examined both during and after the antracycline therapy in comparison to the control group. The prognostic use of the HRECG abnormalities must be established in a larger and longer study. (Fig. 4, Tab. 2, Ref. 43.)

Adolescent↗
PubMed1996

[The circadian cycle of endothelin-1 in healthy persons].

The possible circadian rhythmicity of endothelin-1 was investigated. Radioimmunoassay method was used in 5 clinically healthy male subjects aged 24-32 years. Blood samples were collected at 4-hour intervals over a period of 24 hours. Data for ET-1 were fitted to a 24-hour cosine curve. Statistically significant curves were found in two subjects (maximum at 4 p.m. and minimum at 10 p.m.), one did not yield a statistically significant curve and in two subjects despite the fact that the curves were not presented. Nevertheless, the circadian rhythmicity in our study was not confirmed according to our results it could not be excluded. (Fig. 2, Tab. 2, Ref. 23.)

Adult↗
PubMed1996

[Long-term electrocardiographic monitoring of patients after acute myocardial infarct].

The authors present an account on detailed electrocardiographic follow-up of a patient for 12 months after an inferior myocardial infarction. The patient died 14 months after the IM due to arrhythmia after previous remodelling of the left ventricle. The results assembled by means of superstandard methods of signal averaging electrocardiography (method of cumulative amplitudes, RMS signal and frequency analysis) and electrocardiographie body surface mapping (isointegral maps) are confronted with detailed clinical examinations and repeated echocardiographic investigations. The assembled results indicate that the applied superstandard methods make it possible to extract electrocardiographic parameters (presence of pathological high frequency peaks, raised values of partial cumulative amplitudes at the end of the QRS complex at higher frequencies, negative correlation coefficients from comparisons of integral maps with controls) which are a signal that the patient's life is threatened.

Aged↗
PubMed1996

Morphological findings after intracoronary application of endothelin-1 in dog.

BACKGROUND: Endothelin-1 is a strong vasoconstrictor, high doses of which can cause prolonged vasoconstriction. MAIN PURPOSE: The aim of our study was to investigate as to whether the endothelin-induced vasoconstriction causes irreversible morphological changes in the myocardium in experimental animals and to verify the applicability of this experimental model in the study of the impact of endothelin. METHODS: Fourteen anaesthetized dogs were administered with 400 pmol of endothelin. The substance was applied into the left anterior descending coronary artery. The serum activities of AST, CK and LD enzymes, and changes in electric activity of the myocardium were monitored. The heart of one of the dogs was analyzed morphologically. RESULTS: Following the application of endothelin, vasoconstriction supervened, lasting from 25 to 27 minutes. Five dogs developed fibrillation of ventricles and died. The dogs which survived yielded changes in the activities of the investigated enzymes and changes in electric activity which were typical of focal impairment of the myocardium in sense of necrosis. Morphologically the changes represented disseminated fibrosis or minor scars in the myocardium. CONCLUSIONS: Application of endothelin into the coronary artery can cause irreversible structural changes in the myocardium. (Fig. 1, Ref. 18.).

Animals↗
PubMed1995

[Location of atrial and ventricular insertions of accessory atrioventricular pathways using surface ECG mapping and its importance in catheter ablation therapy].

BACKGROUND: The modern non-pharmacological therapy of the WPW syndrome by means of catheter ablation is based on the interruption of the accessory pathway(-s) by radiofrequency current energy. Destruction of the morphologic substrate of the arrhythmia alters the activation wave spread in the heart. OBJECTIVES: It was the aim of this report to demonstrate the diagnostic potential of BSM in localizing both overt and concealed accessory pathways. Presented study analyzes the alterations of the cardioelectric field by means of body surface ECG mapping in two female patients with accessory pathways before and after their successful curative treatment by radiofrequency catheter ablation. METHODS: Five patients were analyzed prior and after RF catheter ablation by BSM, two of them were selected for this presentation. One patient with WPW syndrome suffered from frequent supraventricular tachycardia due to in one female patient with an overt accessory pathway. The other patient was for several years incessantly in permanent junctional reentry tachycardia due to a concealed accessory pathway. The examination comprised 12-lead ECG, orthogonal vectorcardiogram according to Frank, BSM using a regular 80-electrode-array system and signal-averaged ECG. RESULTS: The RF ablation was successful in both patients and their arrhythmia was abolished. By means of a detailed analysis of the ventricular activation prior RF ablation in the patient with WPW syndrome the precise site of the ventricular insertion of the accessory pathway in the left lateral free wall was predicted. Furthermore, alterations of the terminal QRS complex were observed when comparing pre- versus post-ablation maps. In the second patient the atrial insertion of the accessory pathway with retrograde and decremental conduction was successfully localized to the right septal region by means of pre-ablation BSM. CONCLUSIONS: Both ventricular and atrial activation can be in detail analyzed by means of BSM. Such analysis offers more precise information on the spatial component of the activation wave spread. This case report gives further evidence that BSM is a useful method for precise localization of both ventricular and atrial insertion sites of accessory pathways in patients with paroxysmal tachycardias due to this electrophysiologic abnormality. This information gained recently clinical impact since it can be directly used for faster arrhythmogenic substrate targeting during ablation therapy. (Fig. 5, Ref. 17.)

Adolescent↗