The effect of psychoemotional load on ventricular repolarization reflected in integral body surface potential maps.

The aim of the present study was to investigate the reflection of psychoemotional stress in the body surface potential distribution as documented by isointegral maps of cardiac activation and recovery. In 72 young men (18.3+/- 7.3 y.) with no cardiovascular history body surface potential maps (BSPMs) at rest and during the test of mental arithmetic were recorded. The digitalized data for each point of the QRS, STT and QRST integral maps, for each subject in both situations, were processed and evaluated by methods of univariate as well as spatial mathematical and statistical modeling. The results showed during MA a significant decrease of repolarization integral values over the sternum and right precordium, which contributed to analogically localized decrements also in the QRST BSM. The decrease occurred in more than 2/3 of lead points. The most pronounced changes were observed in the right precordial area, where potentials decreased in more than in 70 % of subjects. In conclusion, the discriminative power of the difference STT and QRST integral maps was strong enough to distinguish the mental arithmetic induced changes in the superficial cardiac electric field. These adrenergic transient alterations in ventricular recovery may be of importance in subjects at risk for ventricular arrhythmias.

[Relation between anthropometric indicators and electrocardiogram variability]. / Vzt'ah antropometrických ukazovatelov a variability elektrokardiogramu.

AIM: To investigate which combination of anthropometrical parameters influence significantly the variability of the magnitude spatial vectors of atrial (sPmax), activation and ventricular (sQRSmax) activation and ventricular depolarization (sTmax). Quantification of these relationships can improve the reliability of criteria for normal values of ECG and VCG characteristics. SUBJECTS AND METHODS: The study group consisted of 195 healthy boys and men without signs of cardiac disease, with normal ECG and VCG, aged from 7 to 70 years, (median = 19 years). Electrocardiologic variables were obtained by Frank lead system in seated persons from a single heartbeat by the computer system Cardiac 128--PC (METE, Prague) in mid respiration. 30 anthropometrical measurements were taken including biceps, triceps, subscapulare and suprailiacare skinfold thicknesses. Proportionality of body and thoracic shape was evaluated according indexes computed from body height, weight (Body mass index, Rohrer and Ponderal index), circumferences (Relative abdominal circumference, Pignet index), anteroposterior and transversal dimensions (Thoracic index, relative sagittal diameter). Values of the 15th and 85th percentil of relevant indexes were taken as criteria for stratification of the sample into three subgroups demarcating the constitutional types. Differences in maximal spatial vector magnitudes between these subgroups were tested by variance analysis ANOVA. Relationships to anthropometrical and vectorcardiographic parameters were expressed also by regression equations. RESULTS: The average magnitudes of maximal spatial vectors increased during maturation and early adulthood: sPmax, approximately up to 17 years, sQRSmax and sTmax up to 22 years. The magnitude of ventricular vectors decreased after this period. With increasing endomorphy, which is indicated by values of Rohrer index, relative abdominal circumference and fat percentage, magnitudes of sPmax, s QRSmax and sTmax decreased (p < 0.001) on the other hand they increased with higher linearity (Ponderal index) and index of fitness (Pignet index). The greatest differences (by 50%) were found in values of sPmax, whereas distributions of ventricular vectors sQRSmax differed by 20-30%. CONCLUSIONS: The variability of magnitudes of maximal spatial vectors was significantly influenced by the proportionality of body constitution independently of age. The tightest relationship of sTmax was found with fat percentage. Influence of anthropometrical parameters was most pronounced in younger adulthood and should be taken into account when evaluating of electrocardiograms and vectorcardiograms.

[Effect of adrenergic stimuli on electrocardiographic and vectorcardiographic characteristics of ventricular repolarization]. / Vplyv adrenergných podnetov na elektrokardiografické a vektorkardiografické charakteristiky repolarizácie komôr.

Autonomic effect of various stimuli on haemodynamic variables is usually tested by changes in blood pressure (BP) and/or heart rate (HR). It is known that increased sympathetic drive of ventricles can interfere with repolarization process. This study was focused on reactive changes of maximal spatial T vector (sTmax), R-R and QTc intervals, in relation to BP changes in 79 boys and men, averaged age 17 +/- 2 years, 36 from them were adolescents with elevated BP (high normal or hypertension I according to WHO/ISH 1999) (ZTK), 19 normotensives (NTK), and 24 normotensive sportsmen. R-R, QTc intervals and maximal spatial T vector were recorded by a PC (Cardiag METE, Prague) with Frank lead system while sitting in mid-respiratory position, during mental arithmetic (MA), after handgrip and during passive head-up tilting to 60 degrees. BP was measured simultaneously by a cuff sphygmomanometer, using phases 1 and 5 of Korotkoff sounds. MA resulted in significant BP increase in all subgroups, however the reactive changes of systolic BP as well as magnitude of R-R shortening, sTmax decline were about two times higher, and in the case of QTc lengthening three times higher in sportsmen. Handgrip provoked in all subgroups in average the less reactive changes of diastolic BP, sTmax, R-R, and QTc intervals. Head-up tilting evoked in all subgroups a significant increase of diastolic BP that was again higher in sportsmen vs. ZTK and NTK. R-R intervals became significantly (p < or = 0.02) and more often shortened in sportsmen vs. ZTK and NTK. Relatively more evident decline of sTmax (more than 20%) in ZTK was the highest change from all observed parameters to all tested stimuli. Our results indicate that for analysis of effect stimuli, which modulate balance in autonomic nervous system, it is helpful to pay attention also to the parameters of repolarization process that may represent a sensitive indicator of sympathetic tonization in myocardial ventricles.

Sensitive markers of the repolarization alterations in systemic hypertension.

INTRODUCTION: The early phase of essential hypertension has been associated with changes in cardiovascular regulation caused by imbalance in some parts of autonomic nervous system. Autonomic effect of various stimuli on haemodynamic variables is usually tested by changes in blood pressure (BP) and/or heart rate (HR). It is known that increased sympathetic drive of ventricles can interfere with repolarization process. THE AIM: This study was focused on reactive changes of maximal spatial T vector (sTmax) and R-R intervals, in relation to BP changes in 79 boys and men, averaged age 17 +/- 2 yrs. 36 from them where adolescents with elevated BP (high normal or hypertension I according to WHO/ISH1999) (EBP), 19 normotensives (NBP), and 24 normotensive sportsmen. R-R intervals and maximal spatial T vector were recorded by a PC (Cardiag METE, Prague) with Frank lead system while sitting in mid-respiratory position, during mental arithmetic (MA) and during passive head-up tilting to 60 degrees. BP was measured simultaneously by a cuff sphygmomanometer, using phases 1 and 5 of Korotkoff sounds. RESULTS: MA resulted in significant BP increase in all subgroups, however the reactive changes of systolic BP as well as magnitude of R-R shortening, and sTmax decline were about two times higher in sportsmen. Head-up tilting evoked in all subgroups a significant increase of diastolic BP that was again higher in sportsmen vs. EBP and NBP. R-R interval became significantly (p < 0.02) and more often shortened in sportsmen than in EBP and NBP. Relatively more evident decline of sTmax (more than 20%) in EBP was the highest change from all observed parameters to both tested stimuli. CONCLUSION: Our results indicate that for analysis of the effect of stimuli, which modulate balance in autonomic nervous system, it is helpful to pay attention also to the parameters of repolarization process that may represent a sensitive indicator of sympathetic tonization in myocardial ventricles. (Tab. 4, Fig. 2, Ref. 27.)

The role of anthropometry in the assessment of vectorcardiographic norms.

There is scarcity of quantitative studies on the relationship between somatometric characteristics of chest configuration and vectorcardiographic variables. The objective of this study was to give a quantitative description of these relations in order to improve the recognition of normal vectorcardiographic ranges and limits. The magnitude of the maximum vector of atrial depolarization is strongly influenced by chest configuration, but not by age, while declination values of atrial activation are under the influence of both factors. The same holds for vectors of ventricular depolarization, while, as regards ventricular repolarization, somatometric variables are only related to the spacial orientation of the vector. Both age and chest configuration also influence the magnitude of the spacial angle between QRS and T integral vectors. These results speak for the need to consider somatometric data for correct assessment of normal limits of VCG variables. (Tab. 6, Fig. 1, Ref. 17.)

Effects of urban noise pollution on blood pressure and heart rate in preschool children.

OBJECTIVE: To investigate the association between long-term exposure to high-level urban traffic noise and blood pressure in preschool children. DESIGN: Normotensive children (n = 1542), aged 3-7 years and attending kindergartens, had their blood pressures and heart rate measured. Mean values of these circulatory variables were related to 24-h equivalent traffic noise emission levels measured near their kindergartens and homes. METHODS: Supine systolic (SBP) and diastolic blood pressure (DBP) were measured by a Doppler ultrasonic device, heart rate by palpitation. Weighted average sound pressure levels were measured for 24 h a working day at 275 places in the city. An anthropometric investigation was performed. Demographic, socio-economic and health status questionnaires were completed by the parents of the children. RESULTS: Children attending kindergartens situated in areas with traffic noise > 60 dB(A) had higher mean SBP and DBP and lower mean heart rate than children in quiet areas. Noise at kindergartens had a greater impact than at homes. CONCLUSIONS: Medium- and high-level urban traffic noise [> 60 dB(A)] near kindergartens is associated in preschool children with higher mean SBP and DBP, and with a higher incidence of children with blood pressure values above the respective 95th centiles. The increase in DBP could be ascribed to the rise in peripheral vascular tone and the decrease in heart rate, possibly owing to activation of a baroreceptor mechanism.

[Orthostatic adaptation of blood pressure and pulse rate in children]. / Ortostatická adaptácia krvného tlaku a pulzovej frekvencie u detí.

Reactivity of blood pressure (BP) and heart rate (HR) to active orthostasis was studied in 1540 children aged 3-7 years. After changing the position from supine to sitting all cardiovascular parameters studied increased significantly. The recorded mean increases were as follows: systolic BP-3-7 Torr, diastolic BP-2 Torr, HR-5-7 beats min-1, pulse pressure 3-6 Torr, mean BP-2-3 Torr. The change to erect position induced a further increase. The reactive increments were in negative correlation with the initial values (r = -0.3, p < 0.001) in both sexes. The incidence of responses with a higher amplitude was significantly higher in children from the lower quartiles of supinal BP distribution. The incidence of reactive BP drop increased gradually from 7 to 14% of cases.