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Clinical Trials as Topic↗
Biomedical subjects
Ljuba Bacharova
Publications and source records attributed to Ljuba Bacharova.
Comparative study of the effects of lacidipine and enalapril on the left ventricular cardiomyocyte remodeling in spontaneously hypertensive rats.
Antihypertensive medications are the most efficient drugs in achieving regression of myocardial hypertrophy in both clinical studies and animal models of hypertension. Nevertheless, there is a lack of clear and concise comparative study of their effects on the modulation of cardiomyocyte morphology and function. Here, we assessed the tissue-protective actions of 2 of these drugs, the calcium channel blocker lacidipine (3 mg/kg/day) and the angiotensin-converting enzyme-inhibitor enalapril (10 mg/kg/day) in vivo, after 8 weeks of treatment of 12-week-old spontaneously hypertensive rats, as well as in vitro, after short-term (4 min) application to isolated cardiomyocytes. Left ventricular hypertrophy (LVH) was compared at organ, tissue, and single-cell level. Our data showed that both drugs prevented the LVH of 20-week-old spontaneously hypertensive rats, but only lacidipine significantly decreased the cardiomyocyte size. Similarly, the single-cell contractility was significantly lowered in lacidipine-treated rats only. The effect of lacidipine was initiated shortly after exposure to the drug in a dose-dependent manner at 0.5 Hz, as well as at 2 Hz, with EC(50) of 10(-7) mol/L. These results can help in understanding the effects of these drugs on the prevention of LVH.
Angiotensin-Converting Enzyme Inhibitors↗
Where is the central terminal located? In search of understanding the use of the Wilson central terminal for production of 9 of the standard 12 electrocardiogram leads.
The aim of this study was to evaluate the understanding of the term central terminal (CT) and to consider the consequences of this level of understanding. A total of 150 questionnaires was distributed during the 30th International Congress of Electrocardiology 2003, Helsinki, Finland; 42 (28%) of the anonymous questionnaires returned were considered adequate for the purpose of this study. The questionnaire addressed the following areas of interest: (1) the location of the CT; (2) the location of the negative poles of unipolar leads ; (3) the naming of the electrocardiogram lead groups; (4) the relationship between the leads and cardiac electrical views; and (5) impact on accuracy of clinical diagnosis. The findings revealed diversity in understanding the basic term, a shift in understanding the term CT to abstract/theoretical understanding, and gaps in understanding the concept of CT and the more recent theories of the cardiac electric field.
Comprehension↗
Relation between QRS amplitude and left ventricular mass in the initial stage of exercise-induced left ventricular hypertrophy in rats.
The aim of the study was to analyze the relationship between QRS amplitude and left ventricular mass (LVM) in early stages of two different experimental models of left ventricular hypertrophy (LVH) in rats: in exercise-induced hypertrophy and pathological hypertrophy due to genetically conditioned pressure overload. Three groups of experimental animals were studied: healthy control Wistar-Kyoto rats (WKYs), spontaneously hypertensive rats (SHRs), and WKY rats exposed to training by intermittent swimming (SWIM). Orthogonal electrocardiograms were recorded in each group at the age of 12 and 20 weeks, and the maximum spatial QRS vector (QRSmax) was calculated. Then the animals were sacrificed and LVM was measured. The specific potential of myocardium (SP) was calculated as a ratio of QRSmax to LVM. The QRSmax values did not follow the changes in LVM. At the end of the follow-up period, the highest values of QRSmax were recorded in the control WKY rats (0.80 +/- 0.05 mV). The QRSmax values in both groups with experimental LVH were significantly lower as compared with control animals (SHR 0.44 +/- 0.02 mV, p < 0.001; SWIM 0.53 +/- 0.04 mV, p < 0.001). Similarly, the SP values were significantly lower in both groups with experimental LVH as compared with control animals (SHR 0.42 +/- 0.02 mV/g, p < 0.001; SWIM 0.55 +/- 0.05 mV/g, p < 0.001). A decrease in QRSmax and SP was observed in both models of experimental LVH. We attributed these findings to the changes in electrogenetic properties of myocardium in the early stage of developing LVH. In other words, it is changes of nonspatial determinants that influence the resultant QRS voltage in terms of the solid angle theory.
Animals↗
The initial stage of left ventricular hypertrophy in spontaneously hypertensive rats is manifested by a decrease in the QRS amplitude/left ventricular mass ratio.
In this study we tested the hypothesis of the relative voltage deficit, i.e. the discrepancy between increased left ventricular mass (LVM) and QRS amplitudes, in an experimental model of spontaneously hypertensive rats (SHR) during the period of a moderate increase in blood pressure. To address this issue we recorded orthogonal electrocardiograms of male SHR at the age of 12 and 20 weeks. During this period the systolic blood pressure (sBP) increased from 165 +/- 3 mmHg to 195 +/- 1 mmHg (p < 0.001). Age and sex matched WKY rats were used as control groups. The sBP values in WKY normotensive control groups were within normal limits (122 +/- 8 mmHg and 130 +/- 4mmHg, respectively). The maximum QRS spatial vector magnitude (QRSmax) was calculated from X, Y, Z amplitudes of the orthogonal electrocardiograms. The animals were sacrificed and the left ventricular mass was weight. The specific potential of myocardium (SP) was calculated as a ratio of QRSmax to LVM. The LVM in SHR (0.86 +/- 0.05 g and 1.05 +/- 0.07 g, respectively) was significantly higher as compared to WKY (0.65 +/- 0.07 g and 0.70 +/- 0.02 g), and the increase of LVM closely correlated with the sBP increase. On the other hand, QRSmax in SHR did not follow either the increase of sBP, or LVM. The QRSmax values in SHR did not differ from those of WKY at the age of 12 weeks (0.59 +/- 0.14 mV compared to 0.46 +/- 0.05 mV), and they were even lower in SHR at the age of 20 weeks (0.74 +/- 0.08 mV compared to 0.44 +/- 0.05 mV, p < 0.001). The values of SP, quantifying the relative voltage deficit, were significantly lower in SHR as compared to the WKY control. The values decreased significantly in SHR with increasing age, sBP and LVM, i.e., with the progression of hypertrophic remodeling of the left ventricle. The results of this study support the hypothesis of the relative voltage deficit in LVH. These results are consistent with the finding of a high number of false negative ECG results in clinical ECG diagnostics of LVH, and could contribute to an understanding of the diagnostic importance of the false negative ECG results, their re-evaluation and utilization for clinical diagnosis and prognosis.
Animals↗
Assessment of management education and training for healthcare providers in the Slovak Republic.
The authors' purpose of this study was to analyze the current system of healthcare managers' education in the Slovak Republic. The study was essentially qualitative and used a triangular approach. This included an analysis of the range of healthcare management education providers, an assessment of needs that was based on questionnaires distributed to a sample of top managers in hospitals, and a focus group discussion. The findings revealed a gap between the estimated needs and the current capacities for management education. The results serve as a baseline for a discussion of future management training and education for healthcare providers in the Slovak Republic.
Health Care Reform↗
Evidence-based medicine. A lesson for electrocardiography?
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Electrocardiography↗
QRS voltage-duration product in the identification of left ventricular hypertrophy in spontaneously hypertensive rats.
OBJECTIVE: Evaluation of the performance of the QRS voltage-duration product (VDP) for detection of left ventricular hypertrophy (LVH) in spontaneously hypertensive rats (SHR). METHODS: Orthogonal electrocardiograms (ECG) were recorded in male SHR at the age of 12 and 20 weeks, when systolic blood pressure (sBP) reached the average values of 165+/-3 mmHg and 195+/-12 mmHg, respectively. Age- and sex- matched normotensive Wistar Kyoto (WKY) rats were used as controls. VDP was calculated as a product of maximum QRS spatial vector magnitude and QRS duration. Left ventricular mass (LVM) was weighed after rats were sacrificed. RESULTS: LVM in SHR at 12 and 20 weeks of age (0.86+/-0.05 g and 1.05+/-0.07 g, respectively) was significantly higher as compared with that in WKY (0.65+/-0.07 g and 0.70+/-0.02 g). The increase in LVM closely correlated with the sBP increase. VDP did not reflect the increase in LVM in SHR. VDP was lower in SHR as compared with that in WKY, and the difference was significant at the age of 20 weeks (18.2mVms compared with 10.7mVms, p<0.01). On the contrary, a significant increase in the VDP was observed in the control WKY at the age of 20 weeks without changes in LVM. The changes in VDP were influenced mainly by the changes in QRSmax. CONCLUSION: LVM was not the major determinant of QRS voltage changes and consequently of the VDP. These data point to the importance of the nonspatial determinants of the recorded QRS voltage in terms of the solid angle theory.
Animals↗