ozlíková K

Remodeling in myocardial infarction and body surface potential maps

This study deals with the capabilities of body surface integral and departure maps to evaluate the chronic stage of myocardial infarction based on dividing the left ventricle into 12 segments. The effects of ventricular remodeling on electrocardiographic potential distributions are considered. A 61-year-old male patient was examined five times by body surface potential mapping during a period of 9 months after acute myocardial infarction. Integral maps were calculated for 60 ms after QRS onset and compared with mean data from a control group using departure maps. Integral maps showed a continual reduction of negative potentials in the lower half of the torso with time. The negative area covered the lower torso in the departure maps during the whole study, but its form and value changed. According to the location of the departure area, the surface projection of the scar moved from a position corresponding to inferior segments to a position corresponding to posterior segments. Its size also decreased. Echocardiographic examinations showed progressive enlargement of both ventricles with time. Therefore, the authors postulate that the changing pattern of body surface potential maps was mainly influenced by ventricular remodeling after myocardial infarction.

Central Systolic Hypertension in Patients with Well-Controlled Hypertension

Background. Central systolic blood pressure (CSBP) has prognostic significance and simplified devices for its estimation have been introduced recently. The aim of this study was to assess the achievement of the target CSBP in treated hypertensive patients. Subjects and Methods. One hundred patients with well-controlled hypertension were analysed. For CSBP estimation, we used the Arteriograph (TensioMed Ltd.), which uses one cuff for all measurements, the “single-point measurement” approach. Results. We found that 62% of patients had CSBP ≥ 130 mmHg, the suggested cut-off value for hypertension. When sex-specific classification was employed (CSBP ≥ 137 mmHg for female and CSBP ≥ 133 mmHg for male), only 13% of patients (mainly women) remained in the hypertensive range. We also found that 55% of patients had a CSBP higher than brachial pressure. Multiple analyses showed that CSBP was significantly associated with sex, height, and return time. Conclusions. A high proportion of treated hypertensive patients had CSBP levels that exceeded their brachial BP. CSBP positively correlated with lower height and shorter return time of the reflected pressure wave and was significantly higher in females compared to males. These findings suggest that, for CSBP classification, it is important to take height and sex-specific differences into account.

Comparison of ventricular depolarization and repolarization in autocorrelation maps of healthy children

The aim of this retrospective study was to analyze the electrocardiographic autocorrelation maps (ACMs) in young people during the time standardized QRST interval assuming some repetition of QRS patterns during the ST interval. We constructed 41 isopotential maps (IPMs) at equidistant intervals (per 20 intervals during QRS complex and ST interval) for 52 children controls (24 boys), mean age (13.6 ± 0.4) years. For each QRST interval, every IPM was compared with every IPM using Pearsons correlation coefficient r. These values were displayed in the form of ACMs. We evaluated only that part of each ACM where the QRS and ST maps were compared, that is 21 QRS IPMs versus 21 ST IPMs. The mean correlation coefficients of single ACMs were 0.054 ± 0.112. The very high positive correlation r ≥ 0.900 covered in average (11 ± 9) % with average value 0.939 ± 0.013. Negative correlations r < 0.000 occurred relatively symmetrically at the ACM borders with the mean value −0.472 ± 0.094 and covered in average (52 ± 9) % of the whole ACM area. From our results follows that the isopotential distribution pattern of the QRS complex is more often repeated in a positive way during the ST interval in girls than in boys.

Biological Signals In Medical Diagnostics

Biological signals—biosignals are material carriers of the information about the state of the biological system of interest. They are the basis of all diagnostic methods. This paper gives an overview of biosignals used in medicine, their classification and processing.

Electric instability after myocardial infarction displayed in body surface potential maps

A longitudinal study during the first year after myocardial infarction (MI) was performed in 12 patients (pts) to evaluate the reversibility of the electric heart field changes occurring during the acute phase by means of body surface potential mapping (BSPM). Using correlation coefficients we showed that the inversion of electric processes in myocardial depolarization and/or repolarization during acute phase of MI displays irreversible damage of the myocardium that means high risk for the pt and that the healing of infarcted heart is not completed within 6 months after MI at least from the electrical point of view.