[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.)

Modelling developmental changes of human cardiac electric field in early postnatal period.

In early postnatal life, human cardiac electric field undergoes dramatic changes resulting from the adaptation of the heart to new hemodynamic conditions. For the study of the effect of changes in ventricular geometry as well as in spatial orientation of the heart occurring in this period of life, on the resultant heart vectors, our computer model of propagated activation was used. This model allows to change both mentioned characteristics of ventricles so that they reflect the developmental changes in the human heart. The pattern of activation of the model of newborn heart, characterized by equal thicknesses of the left and right ventricular walls as well as by the planar shape of the septum, showed that the resulting electrical forces were oriented anteriorly, slightly to the right, with clockwise rotation of the cardiac vectorgram in the horizontal plane projection. The gradual increase of the left ventricular wall thickness shifted the cardiac vector loop gradually to the left and anteriorly. When the ratio of the left to right ventricular wall thickness was the same as in adult human heart, the cardiac vector loop was oriented posteriorly, to the left and inferiorly. The left orientation of the initial cardiac vectors, commonly observed in 50% of full-term babies until 24 hrs of life, could be achieved only by the rotation of the heart around its long axis and/or by change of the azimuth of this axis. The simulated cardiac vectorgrams followed the typical early postnatal evolution of the vectorcardiograms of human newborns. (Fig. 4, Ref. 9.)

Blood pressure and heart rate response to head-up position in full-term newborns.

The reactions of heart rate (HR), systolic (sBP) and diastolic (dBP) blood pressure were studied in response to passive head-up tilting (successively to +45 degrees and +90 degrees) in a group of 83 full-term, 1- to 7-day-old newborns who were quiet and awake. A significant mean increase of HR was noted for the whole group, from 121 +/- 14 beats/min to 124 +/- 15 beats/min at +45 degrees and to 127 +/- 17 beats/min at +90 degrees, while sBP rose from 65 +/- 9 mmHg to 67 +/- 12 mmHg at +45 degrees and to 70 +/- 13 mmHg at +90 degrees tilts, respectively (5th post-tilt min). A negative correlation (r = -0.41, P < 0.01) was found between basal supine values of HR and their post-tilt increments after +45 degrees tilting. After +90 degrees tilting, dBP correlated negatively (r = -0.33, P < 0.003) with the supine values, as well as HR (r = -0.30, P < 0.01). Breaking down the whole group according to age has shown that in 1-day-old babies (N = 11), the only one significant mean change was an increase of HR by 7 +/- 10 beats/min after the +45 degrees tilt. At the age of 2 days (N = 36), the group mean values showed a rise of sBP only by 5 +/- 12 mmHg after the +90 degrees tilt. In 3-day-old babies (N = 18), increased values were noted in both the HR (by 6 +/- 18 beats/min) and sBP (by 5 +/- 15 mmHg) even after the +45 degrees tilt. The increase of all the variable: HR by 7 +/- 12 beats/min, sBP by 6 +/- 8 mmHg, dBP by 2 +/- 4 mmHg after 5 min of +90 degrees tilt was present only in 4- to 7-day-old neonates (N = 18). It seems that the evolution of orthostatic circulatory regulation is a component of the evolution in the overall responsiveness of the cardiovascular system to external stimuli and becomes apparent after a relative stabilization of the neonatal blood volume on the 2nd-3rd postnatal day.

[Effects of postural changes on blood pressure and pulse rate in neonates]. / Posturálne zmeny krvného tlaku a pulzovej frekvencie u novorodencov.

Information about the effect of body position on blood pressure (BP) in neonates is rare and controversial. The aim of the present study was to investigate the type of orthostatic reaction and it s incidence in a group of infants in relation to basal resting values of BP and heart rate (HR). BP and HR were measured in 125 full-term neonates in the supine position and in the 2nd minute after changing the position by lifting on arms to 90 degrees. The reactive values of BP and HR were significantly higher, p < 0.001 (71 +/- 12 compared to 66 +/- 9 Torr in systolic BP, 41 +/- 8 to 37 +/- 6 in diastolic BP, and 127 +/- 19 to 120 +/- 8.min-1 in HR). In the head-up position an increase in BP and HR was observed in about 70% of neonates, whereas their basal supine BP values of 66/36 Torr were significantly lower compared to the values of 69/40 Torr recorded in neonates whose BP decreased in the head-up position. These differences were significant (p < 0.01 syst. and p < 0.001 diast.). (Fig. 3, Ref. 15.).

[Normal blood pressure values in neonates and physiologic factors in its variability]. / Normálne hodnoty krvného tlaku u novorodencov a fyziologické faktory jeho variability.

Noninvasive examination of blood pressure by ultrasound sphygmomanometry (LUD 802-TESLA) carried out in 150 physiologic neonates provided insight into resting values of systolic and diastolic blood pressure and heart rate in this series of our urban population (mean value on postnatal day 2:64 +/- 10/36 +/- 7 Torr--8.5 +/- 1.3/5 +/- 0.9 kPa, HR 119 +/- 11. min-1). The paper quantifies the postnatal development of blood pressure over the first days of life, as well as the gradual differentiation of values in wakefulness and sleep and reactive changes at food intake, changes of posture, and at crying. Our original finding of circadian blood pressure variation already in the first postnatal days has been confirmed, with individual blood pressure chronograms exhibiting a predominance of the ultradian component.