Biomedical subjects

O Kittnar

Publications and source records attributed to O Kittnar.

At least 19 recordsLinked to original sources

PubMed2006

ECG body surface mapping (BSM) in type 1 diabetic patients.

Diabetes mellitus is a risk factor of cardiovascular diseases. ECG of patients with diabetes mellitus type 1 (DM 1) shows tachycardia (block of parasympathetic innervation) and abnormal repolarization (increased QT interval and QT dispersion (QTd)) indicating a risk of ventricular tachycardia and sudden death in young people with DM 1. The aim of the present report was to measure 145 parameters of the heart electric field in 22 patients (14 men, 8 women) with DM 1 without complications (mean age 32.8+/-11.4 years) and in 22 controls (11 men, 11 women, mean age 30.1+/-3.4 years). The duration of diabetes was 13.9+/-7.8 years. The parameters were registered by the diagnostic system Cardiag 112.2 and statistically evaluated by the Student and Mann-Whitney test. Tachycardia (86.3+/-2.7 beats.min(-1)), shortening of both QRS (79.9+/-1.6 ms) and QT (349.0+/-5.9 ms) and increased QT dispersion (115+/-36 ms) were observed in DM 1 when compared with the controls (75.0+/-2.1 beats. min.(-1), QRS 89.9+/-2.7 ms, QT 374.0+/-4.4 ms, QTd 34.0+/-12.0 ms, p<0.01). The QTc was 415.2+/-4.1 ms in DM 1 and 401.4+/-6.6 ms in controls (NS). Other significant findings in DM 1 were: higher maximum of depolarization isopotential maps (DIPMmax) in the initial phase of QRS and less positive in the terminal phase, more negative minimum (DIPMmin) during QRS similarly as the minimum in depolarization isointegral maps (DIIMmin) and the minimum in isointegral map of the Q wave (Q-IIMmin), lower maximum in repolarization isopotential maps (RIPMmax) and less negative minimum (RIPMmin), more negative amplitude of Q wave (Q-IPMAM) and more pronounced spread of depolarization (activation time). Our results confirmed a decreased parasympathetic to sympathetic tone ratio (tachycardia, shortening of the activation time) and revealed different depolarization and repolarization patterns in DM 1. The differences in heart electric field parameters measured by the BSPM method in DM 1 and in the controls indicate the importance of ECG examination of diabetic patients type 1 in the prevention of cardiovascular diseases.

Action Potentials↗

PubMed2004

Hemodynamic response to laparoscopic cholecystectomy--impacts of increased afterload and ischemic dysfunction of the left ventricle.

The authors describe the results of intra-operative hemodynamic monitoring during laparoscopic cholecystectomy in patients with ischemic left ventricular dysfunction and with significant aortic stenosis. The results in the groups composed of 13 and 12 patients were compared with the findings in 10 young, non-obese, non-smokers without significant cardiovascular history and with normal findings during resting transthoracic echocardiography. Monitoring itself was conducted using transesophageal echocardiography 1) after the induction of anesthesia, 2) after the induction of capnoperitoneum, and 3) after setting the operative anti-Trendelenburg position. The measurements were performed at least in triplicate and the results were processed using ANOVA test. Significant differences were identified in the time course patterns of heart rate, mean arterial pressure, dual product (pressure-rate-product), and cardiac output. In terms of pathophysiology, we believe that the most important achievement was the identification of different time course patterns of individual parameters in the respective groups. The results in the group of patients with aortic stenosis were based particularly on the different time course of the mean arterial pressure, while the results in patients with ischemic disease were more dependent on the time course of the heart rate. Very interesting is a drop of peripheral vascular resistance after positioning of these patients which could be explained only partially by a beta-blocking or ACEI medication. In clinical terms, the most important finding was probably that no complications occurred in the entire group of 35 patients, of which 25 suffered from severe organic cardiopathies.

Aortic Valve Stenosis↗

PubMed2004

QT dispersion and electrical heart field morphology in patients treated with dosulepin.

The aim of the study was to detect the changes of QT dispersion (QTd) due to cardiotoxicity of tricyclic antidepressant dosulepin. Electrocardiographic and vectorcardiographic recordings were obtained using Cardiag 112.2 diagnostic system from 28 psychiatric outpatients treated with prophylactic doses of dosulepin and compared to those obtained from 37 healthy volunteers. From these recordings following parameters were evaluated: QTd, spatial QRS-STT angle and amplitude of T-wave. The acquired data were correlated with the dosulepin plasma levels using Spearman's rank order correlation test. The average QTd (+/-S.D.) in the dosulepin group was significantly higher (70+/-21 ms) than that in the control group (34+/-12 ms) (P<0.001). Moreover, the correlation between QTd and the dosulepin plasma levels was highly significant (r = 0.7871, P<0.001). Similar results were obtained when QTc dispersion was used. On the contrary, the QRS-STT space angle did not correlate with the dosulepin plasma levels. Furthermore, the T-wave amplitude was not significantly correlated to the QT-interval. Thus we can conclude that the QT dispersion could be used as a simple marker of the dosulepin effect on the myocardium.

Adult↗

PubMed2004

QT dispersion estimated from 80 body surface potential map leads and from standard 12-leads ECG in psychiatric patients treated with dosulepin.

The aim of the study was to detect changes of the QT dispersion (QTd) due to cardiotoxicity of tricyclic antidepressant dosulepin. Electrocardiographic and body surface potential mapping (BSPM) recordings were obtained using Cardiag 112.2 diagnostic system from 27 psychiatric outpatients treated with prophylactic doses of dosulepin and compared to those obtained from 37 healthy volunteers. From these recordings the QTd and the dispersion of heart rate-corrected QT interval QTc were evaluated. These parameters were estimated both from 80 BSPM leads and from 12 standard ECG leads. Acquired data were statistically correlated by Spearman rank order correlation coefficient with dosulepin plasma levels. The average QTd evaluated from BSPM leads (+/-SD) in the dosulepin group was significantly higher [70 (+/-21) ms] than that in the control group [34 (+/-12) ms] (P< 0.001). Moreover, the correlation between QTd and the dosulepin plasma level was statistically significant as well (P< 0.001) with the value of correlation coefficient 0.7871. The QTd evaluated from standard 12 ECG leads was increased in dosulepin group as well [46 (+/-18) ms vs. 28 (+/-10) ms - P< 0.05] but we have not found any significant correlation of the QTd with the dosulepin plasma level. According to the above-mentioned results we can conclude that the QTd estimated from BSPM leads (but not that estimated from 12-lead ECG) could be used as a marker of the dosulepin effect on the myocardium.

Adult↗

PubMed2004

[Dispersion of QT intervals--a myth or a diagnostic symptom?].

BACKGROUND: QT interval dispersion (QTd) is conventionally interpreted as a result of repolarization heterogeneity in ventricular myocardium. However, another concept of QTd origin has been discussed recently, suggesting that different projections of the repolarization vector into individual ECG leads could be responsible for the differences in QT interval duration. Moreover, the reproducibility could be influenced by factors both electrocardiographic (T wave amplitude, U wave) and extracardiac (noise, ECG measures). In the presented study we have followed the QTd in two groups of patients with proved changes of an electric heart field. METHODS AND RESULTS: Studied groups: 1. Control group, 2. Healthy pregnant women, 3. Patients treated with dosulepine. QT interval was measured from 80 unipolar chest leads used for body surface potential mapping. The QTd was significantly higher in both experimental groups in comparison with the control group (p < 0.001). Significant correlation was found between the QTd and dosulepine plasma level (p < 0.001). Also amplitude of the T wave loop was in both groups decreased and its width increased (both p < 0.001). CONCLUSIONS: If appropriate procedure of measurement is used, the QTd is significantly increased in many physiological and pathological states. Clinical relevancy of borderline increased values has to be interpreted very carefully.

Adult↗

PubMed2004

[Significance of the mathematical model of cardiac electrical field for the interpretation of experimental data].

BACKGROUND: In concurrence of our recent findings of the elevation of QT dispersion (QTd) in the group of pregnant women, mathematical approaches were developed aimed to give possible geometrical explanation whether the observed changes result from the rotation or from the changed position of the heart. METHODS AND RESULTS: Mathematical model of the cardiac electrical field approximated as a time variable dipole in a homogenous spatial conductor was developed. From the experimental vectocardiographic records, representing time course of the cardiac dipole, body surface potential maps were calculated on the basis of the model. To validate the adequacy of the model, the reconstructed electrocardiograms were compared with the empiric data. To determine the effects of rotation, original empiric VCG data of the control group were transformed accordingly the hypothetic pregnancy related changes. Calculated surface electrocardiograms were then compared with empiric cardiograms of the pregnant women. CONCLUSIONS: Based on the results, several conclusions can be drawn: 1) QT dispersion is associated also with the geometrical relations between the direction of cardiac vector during the terminal phase of repolarization and the direction of axes in the given system of leads. The dispersion then has its typical occurrence at the thoracic surface--minimums of the QT duration are found in the plane perpendicular to the axis of the terminal vector lead. 2) When the duration of repolarization is estimated from the classic thoracic leads within the phisiological variations of terminal-depolarization vector orientations, can exist that in some cases the minimum of QT interval is and in others it is not recorded by the lead system. Value of QT dispersion between these two extremes will be significantly different. 3) In case of the horizontal declination of the heart, the ECG signal in most of the leads of the body surface mapping has a higher voltage than in case of vertical declination due to a smaller angle between axes of the terminal vector and most of the leads. Such fact will contribute to more accurate reading of the T wave end and to the estimation of QT interval, usually with smaller value of QTd. 4) The change of the cardiac electrical field corresponding to the changed position of the heart (rotation) does not result by itself in QTd changes, if it is evaluated from the records from the whole thorax. Obversely, horizontalization of the heart contributes more to the evaluation of lower QTd values, as it is given above. 5) More then the result of geometrical changes, QT dispersion found in the group women in high level of pregnancy is an effect of changes in the T loop morphology, which was observed in this group. Another possible explanation of the observed dispersion is the non-dipolar character of the electrical field changes during pregnancy.

Adult↗

PubMed2004

Electrocardiographic body surface maps (BSM) in patients with ischemic heart disease examined by coronary angiography.

ECG body surface maps (BSM) is one of the noninvasive methods for the detection of ischemic heart disease. In the present work we registered the BSM in 25 patients, 18 men, mean age 56.8 (31-83) years, 7 women, mean age 58.7 (43-72) years with coronary artery disease and in 23 healthy persons, 17 men, mean age 55 (46-60) years, 6 women, mean age 57 (42-70) years. Using diagnostic system Cardiag we measured 32 parameters of heart electric field (ECG, VCG, isopotential, isointegral, and isoarea maps). The results of BSM examination were compared with the results of coronary angiography (CAG) and other noninvasive methods. Twenty-four patients were BSM positive, 5 of them with negative CAG. In one case both BSM and CAG were negative. None of persons with positive CAG were BSM negative. The values of positive BSM in patients with negative CAG approached more to the values of positive CAG persons than to controls. Despite of small number of persons examined in our study one can conclude that the BSM method detects the damage of myocardium by another way than the CAG.

Adult↗

PubMed2002

Changes of the electrical heart field and hemodynamic parameters in the 34th to 40th weeks of pregnancy and after delivery.

We have studied changes of the electrical heart field resulting from the changed spatial position of the heart during the last period of pregnancy in healthy women. This was suggested to be a good model of electrocardiographic changes that could be found on patients suffering from obesity. The measured parameters of the electrical heart field were compared with hemodynamic parameters before and after delivery in the group of non-obese women with physiological pregnancy and in a group of healthy non-obese and non-pregnant women. Several significant changes of the electrical heart field were detected in the late pregnancy: increased heart rate, shortening of A-V conductance, prolongation of QT interval normalised for the heart rate and changes in the ventricular depolarisation and repolarisation patterns. Some of these changes are not fully restored in 4 days after delivery. Moreover, we have found an increased pump function of the left ventricle accompanied by decreased peripheral resistance in the group of pregnant women. Increased pump function was partially restored after delivery, peripheral resistance was not only restored, but it overshot to increased values. Persisting elevated heart rate with increased peripheral resistance suggested increased sympathetic activity after birth. Only some changes of electrical heart field could be explained by changed spatial arrangement of the chest organs during pregnancy and they must be considered in a complex consequence with changes in regulatory mechanisms.

Adult↗

PubMed2002

QT dispersion and T-loop morphology in late pregnancy and after delivery.

The aim of the study was to detect changes of both the QT dispersion and T-loop morphology resulting from the changed spatial position of the heart during pregnancy. Electrocardiographic and vectorcardiographic recordings were obtained from 37 healthy women 19-36 years old in the 36th to 40th week of physiological pregnancy and 2 to 6 days after delivery. The same recordings were obtained from 18 healthy women of the same age. The average QT dispersion (+/- S.D.) in normal subjects was significantly lower (34 +/- 12 ms) than in those in late pregnancy (73 +/- 18 ms) (P < 0.001). The average amplitude of T-loop (Ta) in women in late pregnancy was significantly (P < 0.001) smaller (532 +/- 98 microV) and the width of T-loop (Tw) was wider (21.24 +/- 11.48 deg) than in the control group (793 +/- 114 microV and 7.17 +/- 3.02 deg, respectively). The partial post-partum restoration of all parameters was not significant. In all groups, the QT dispersion was significantly correlated with Tw but not with Ta. According to these results we can conclude that the QT dispersion is an indirect reflection of the complete process of ventricular repolarization, reflected in the morphology of the T-loop.

Adult↗

PubMed2002

Electrocardiogram, vectocardiogram and body surface maps in patients with panic disorder.

An increased risk of myocardial ischemic changes was demonstrated in patients suffering from panic disorder (PD). Using classical ECG methods, this risk cannot be evaluated in most patients. We measured the vectocardiogram (VCG) using Frank orthogonal leads and body surface maps (BSM) including 12-lead ECG. In our study of 11 PD patients (2 men, 9 women), without any seizures and pharmacological treatment and without cardiovascular symptoms, we found marked sinus tachycardia (heart rate 90.1 +/- 12.2 min(-1)) and a shorter R-R interval (678 +/- 93.6 ms) than in 27 controls (heart rate 73.6 +/- 7.7min(-1), R-R 822.7 +/- 86.4 ms) (5 men, 22 women) (p<0.001). The VCG measured spatial QRS-STT angle was more opened (70.3 +/- 24.5 degrees) than in the control group (49.5 +/- 19.5 degrees) (p<0.05). The maximum (extremum) in depolarization (DIAM max 30, 40) and repolarization (RIAM max 35) of body surface isoarea and isointegral (RIIM max) maps was less positive (p<0.001) and the minimum (DIAM min 40) was less negative than in the controls (p<0.05) even in the period free of a panic attack. Our results showed the changes in the heart electric field parameters occurred in PD patients when compared to the control group.

Adult↗

PubMed2001

[QT interval dispersion].

Dispersion of QT intervals has been proposed as a measure of repolarization process inhomogeneity (and thus refractority inhomogeneity) of ventricular myocardium. Recently other possible explanation of this phenomenon has been intensively discussed. According to this concept QT dispersion is explained by different projections of the heart repolarization vector. Moreover, the reproducibility of the measurement of QT dispersion is rather low as it could be influenced both by intrinsic (e.g., amplitude of the T wave or U wave) and extrinsic (e.g. noise, amplitude and time parameters of recording) factors. Only markedly prolonged QT dispersion must be therefore interpreted as a sign of the abnormal course of the repolarization. Nevertheless, according to all mentioned facts the only serious interpretation of increased QT dispersion is that it reflects unspecific repolarization changes. More precious explanation is by then not possible (and it is disputable if it ever will be).

Animals↗

PubMed2001

Mathematical model of the electromechanical heart contractile system--regulatory subsystem physiological considerations.

The biochemical model of excitation-contraction coupling in cardiomyocyte is presented and the validity of simulations of both physiological and pathological processes is discussed. The model of regulatory and actomyosin subsystems, even if it is rather simple in its regulatory subunit, gives results well consistent with experimental data. Specifically, intracellular free calcium levels ([Ca2+]i) were computed under various states of sarcoendoplasmic reticular Ca2+-ATPase (SERCA2) and compared to experimental findings. Computed results reproduced well both the increase in resting [Ca2+]i level and the attenuation of [Ca2+]i decline commonly observed in heart failure. Thus the computational simulations could help to identify core relations in studied systems by comparing results obtained using similar models of various complexities.

Actomyosin↗

PubMed2001

ECG body surface isointegral and isoarea maps (BSM) in 30 and 60-years-old healthy humans.

ECG body surface isointegral and isoarea maps (BSM) are the sensitive indications of local electrical depolarization and repolarization changes both in controls and in coronary artery disease. In the present work the absolute values of maximum and minimum (extremum) in BSM have been compared in 24 healthy persons (20-36 years) with 18 older ones (54-70) of both sexes, non-smokers and without cardiovascular diseases in their medical history. Twenty-nine parameters of the heart electric field were registered by 96 unipolar electrodes placed regularly on the thorax and analyzed by the system Cardiag. A lower heart rate and a longer QT interval were found in older persons. The maximum (extremum) of isointegral and isoarea maps was less positive and the minimum was less negative in the older than in the younger subjects (p < 0.01). The maximum Q-wave amplitude on surface thorax was significantly lowers in older than in younger persons. The results confirmed the age-dependent decrease of QRS and T wave potentials.

Adult↗

PubMed2001

[Effect of a 10-day animal fat-free diet on cholesterol and glucose serum levels, blood pressure and body weight in 50-year-old volunteers].

The morbidity and mortality of cardiovascular diseases is high in developed countries including Czech Republic. The lifestyle decreases it in 50%. The aim of this work was to ascertain if the short lasting stay without stress and with vegetarian diet (without eggs) and physical activity is able to decrease the main risk factors of cardiovascular diseases. In 106 volunteers, mean age 49.1 (+/- 14.1) years, 83 women and 23 men, the body weight, blood pressure, serum cholesterol and blood glucose (Accutrend GC, Boehringer, Mannheim, BRD) have been measured before and after the stay at the same conditions. Eighty persons were healthy, seven persons with essential hypertension, eight persons with ischemic heart disease, four persons with diabetes mellitus and seven persons with other than cardiovascular diseases. In some persons the lipid spectrum was measured. Cholesterol decreased in blood serum from 4.9 to 4.3 mmol/l (11%--p < 0.01), blood glucose decreased from 4.2 to 3.3 mmol/l (p < 0.05), blood pressure systolic from 121.5 to 117.4 mm Hg (p < 0.01) and diastolic from 76.5 to 73.8 mm Hg (p < 0.05), body weight was not significantly changed. Our results showed, that 10-days lasting stay containing vegetarian diet and physical activity decreased the risk factors of cardiovascular diseases in 50 years-old volunteers.

Blood Glucose↗

PubMed1998

Antidepressant drugs and heart electrical field.

Some antidepressant drugs, especially tricyclic ones--(TCA), have cardiovascular side effects. To compare the effects of antidepressant drugs, the electrocardiogram (ECG), vectorcardiogram (VCG), and body surface maps (BSM) were recorded in psychiatric patients without cardiovascular diseases treated by a) TCA amitriptyline or dosulepin (daily dose 50-200 mg, 22 patients), b) lithium (serum level 0.66 +/- 0.08 meq/l, 21 patients), c) selective serotonine reuptake inhibitor citalopram (daily doses 20-60 mg, 30 patients), and in 23 control patients. In the TCA-treated patients, the heart rate was increased, QT and RR intervals shortened (p < 0.01, antimuscarinic effect). This was not observed in lithium- and citalopram-treated patients. All antidepressants decreased the absolute maximum values of depolarization isointegral maps, lithium and TCA reduced the initial and citalopram the later phase of depolarization. Citalopram slightly diminished the amplitude of the R wave. The results confirm the antimuscarinic effects of TCA in therapeutic doses and specify the intraventricular effects of antidepressants.

Adult↗

PubMed1997

[Classification of physico-mechanical mechanisms in primary hypertension].

Arterial hypertension (AH) is a serious disease with high prevalence in the developed countries. In majority of the AH cases, their origin stays unknown (primary AH). There is a great number of variants in primary AH illustrating the complexity of the disease pathogenesis. We tried out to define a classification of primary AH based on the biomechanical mechanisms of elevated blood pressure, though we accept that the pathogenesis of AH includes also malfunction of one (or more) control mechanism for the initiation of compensation. We have brought some examples of unhomologated data in the literature dealing with flow conditions in the vascular system. This may explain the underestimation of the role of the rheological properties of the blood and the function of precapillary sphincters in the ethiopathogenesis of AH.

Hemodynamics↗

PubMed1996

Three-dimensional finite element computer model of the forward problem of electrocardiology.

This study analyses forward problem of electrocardiology. Premature beats originated from subepicardial layer of myocardium were simulated in order to analyse their shape dependence on the site of origin. The equation governing the propagation of the electrical wave through human thorax together with transition and boundary conditions is derived under the clearly stated simplifying assumptions. The weak formulation of the forward problem of electrocardiology is introduced, too. The Galerkin method as a convenient tool for looking for the numerical solution is mentioned and its practical implementation--finite element method--then used in order to obtain numerical results. The obtained results were presented in the form of isopotential maps and compared with actually measured body surface isopotential maps of the depolarization phase. The parameters of the model were then optimalized in accordance with the measured data. In spite of the lack of quantitative data the model has proved that the presented method was able to be used for the simulation studies of ventricular ectopic beats. It was shown that only a small difference between the site of beat origin can be well distinguished on the simulated body surface maps. (Fig. 3, Ref. 3.)

Computer Simulation↗

PubMed1993

Quantitative evaluation of body surface potential mapping of heart electrical field in ischaemic heart disease.

New possibilities of quantitative evaluation of body surface potential mapping were studied in 78 patients with ischaemic heart disease. Integral maps of the Q wave, QRS and ST-T intervals were plotted and isochronous maps of ventricular activation time and maps of asynchronous potential minima of the Q wave were determined. Minimum and maximum potential values and their time relations were evaluated in the maps. Left ventricular contraction abnormality detected by left ventricular angiography was determined by a point score and expressed as an index of asynergy. The number of coronary artery branches with significant narrowing was assessed and the extent of coronary artery damage was evaluated by an arbitrary defined index. Using quantitative parameters from the maps, multiple stepwise linear regression was performed. The relationship between map parameters and index of asynergy corresponded to multiple correlation coefficient r = 0.69 (p = 0.01) in the whole group of patients. In the group of patients with left ventricular contraction abnormality the relationship between these parameters was found to be r = 0.87 (p = 0.01). The relationship between map parameters and the number of coronary artery branches with significant stenosis was r = 0.60 (p = 0.01) in the group of patients with positive coronary angiography. In the same group of patients the relationship between map parameters and the index evaluating coronary artery damage was equal to r = 0.63 (p = 0.01). The data obtained from body surface integral maps enable to quantify cardiac ischaemic damage.

Coronary Angiography↗