Phototherapy is the most effective non-invasive method of neonatal hyperbilirubinemia treatment. Application of this method can be associated with side effects including changes in the cardiovascular system. During phototherapy, the primary effects in the cardiovascular system include cutaneous vasodilation leading to skin hyperperfusion and subsequent redistribution of blood. The increased blood flow through the skin is associated with increased transepidermal water loss. Further effects include an increase in cerebral blood flow. Redistribution of blood to the cutaneous bed is compensated by hypoperfusion in the splanchnic area (mostly postprandial) and a significant reduction of the renal blood flow. Regarding closure/reopening of the ductus arteriosus, the results suggest that that phototherapy does not affect ductal patency. During phototherapy the cardiac output can be slightly reduced due to a decreased stroke volume, especially in preterm newborns. Systemic blood pressure is decreased and heart rate is elevated in both preterm and term newborns during phototherapy. The heart rate variability is slightly reduced. Symbolic dynamics analysis of the short-term HRV showed that during phototherapy the activity of the ANS regulating the heart rate is shifted towards the dominancy of the sympathetic activity. The responses in the cardiovascular system of premature/mature newborns without other pathology confirm a well physiologically functioning control of this system, even under specific conditions of phototherapy.

• MeSH
• fototerapie škodlivé účinky   metody   MeSH
• lidé MeSH
• minutový srdeční výdej MeSH
• novorozenec MeSH
• otevřená tepenná dučej * etiologie   MeSH
• srdce * fyziologie   MeSH
• Check Tag
• lidé MeSH
• novorozenec MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH

To characterize the differences in baroreflex sensitivity (BRS), blood pressure (BP), heart rate (HR) and respiration rate (RR) in preterm infants with a similar postconceptional age reached by various combinations of gestational and postnatal ages. To detect potential sex differences in assessed cardiovascular parameters. The study included 49 children (24 boys and 25 girls), postconceptional age 34.6+/-1.9 weeks. Two subgroups of infants were selected with the similar postconceptional age (PcA) and current weight, but differing in gestational (GA) and postnatal (PnA) ages, as well as two matched subgroups of boys and girls. Blood pressure (BP) was recorded continuously using Portapres device (FMS). A stationary segment of 250 beat-to-beat BP values was analyzed for each child. Baroreflex sensitivity (BRS) was calculated by cross-correlation sequence method. Despite the same PcA age and current weight, children with longer GA had higher BRS, diastolic and mean BP than children with shorter GA and longer PnA age. Postconceptional age in preterm infants is a parameter of maturation better predicting baroreflex sensitivity and blood pressure values compared to postnatal age. Sex related differences in BRS, BP, HR and RR were not found in our group of preterm infants.

• MeSH
• baroreflex * MeSH
• časové faktory MeSH
• dechová frekvence MeSH
• gestační stáří MeSH
• kojenec MeSH
• krevní tlak * MeSH
• lidé MeSH
• novorozenec nedonošený * MeSH
• novorozenec MeSH
• předčasný porod patofyziologie   MeSH
• sexuální faktory MeSH
• srdeční frekvence * MeSH
• věkové faktory MeSH
• Check Tag
• kojenec MeSH
• lidé MeSH
• mužské pohlaví MeSH
• novorozenec MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH

Arterial compliance (C) is a complex parameter influencing ventricular-arterial coupling depending on structural (arterial wall remodeling) and functional (blood pressure, smooth muscles tone) changes. Based on Windkessel model, C can be calculated as the ratio of a time constant Tau characterizing diastolic blood pressure decay and total peripheral resistance (TPR). The aim of this study was to assess changes of C in the context of systolic arterial pressure (SAP) perturbations during four physiological states (supine rest, head-up tilt, supine recovery, mental arithmetic). In order to compare pressure independent changes of C a new index of C120 was proposed predicting C value at 120 mm Hg of SAP. Eighty-one healthy young subjects (48 f, average age 18.6 years) were examined. Hemodynamic parameters were measured beat-to-beat using volume-clamp photoplethysmographic method and impedance cardiography. We observed that C was strongly related to SAP values on the beat-to-beat time scale. Interestingly, C120 decreased significantly during stress phases. In conclusion, potential changes of SAP should be considered when measuring C. Arterial compliance changes in the opposite direction to TPR pointing towards influence of vascular tone changes on its value.

• MeSH
• arteriální tlak * MeSH
• časové faktory MeSH
• cévní rezistence MeSH
• fyziologická adaptace MeSH
• lidé MeSH
• matematické pojmy MeSH
• mladiství MeSH
• mladý dospělý MeSH
• modely kardiovaskulární MeSH
• polohování pacienta MeSH
• supinační poloha MeSH
• systola MeSH
• test na nakloněné rovině MeSH
• tuhost cévní stěny * MeSH
• zdraví dobrovolníci pro lékařské studie MeSH
• Check Tag
• lidé MeSH
• mladiství MeSH
• mladý dospělý MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• srovnávací studie MeSH

Beta-adrenergic receptors (beta-ARs) play a pivotal role in the cardiovascular regulation. In the human heart beta1- and beta2-ARs dominate in atria as well as in ventricle influencing heart rate and myocardial contractility. Some single nucleotide polymorphisms (SNPs) of beta-ARs might influence cardiovascular function. However, the influence of beta-AR genes SNPs on hemodynamic parameters at rest and their reactivity under stress is still not well known. We aimed to explore the associations between four selected beta-ARs gene polymorphisms and selected cardiovascular measures in eighty-seven young healthy subjects. While in beta1-AR polymorphism rs1801252 no significant association was observed, second beta1-AR polymorphism rs1801253 was associated with decreased cardiac output and cardiac index during all phases and with decreased flow time corrected and ejection time index at rest and during mental arithmetics. Polymorphism rs1042713 in beta2-AR was associated with alterations in blood pressure variability at rest and during head-up-tilt, while rs1042714 was associated predominantly with decreased parameters of cardiac contractility at rest and during mental arithmetics. We conclude that complex analysis of various cardiovascular characteristics related to the strength of cardiac contraction and blood pressure variability can reveal subtle differences in cardiovascular sympathetic nervous control associated with beta-ARs polymorphisms.

• MeSH
• beta-1-adrenergní receptory genetika   MeSH
• beta-2-adrenergní receptory genetika   MeSH
• fenotyp MeSH
• funkce levé komory srdeční genetika   MeSH
• genotyp MeSH
• jednonukleotidový polymorfismus * MeSH
• kontrakce myokardu genetika   MeSH
• krevní tlak genetika   MeSH
• lidé MeSH
• mladiství MeSH
• mladý dospělý MeSH
• zdraví dobrovolníci pro lékařské studie MeSH
• Check Tag
• lidé MeSH
• mladiství MeSH
• mladý dospělý MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH

Úvod: Dynamika vývoja kardiovaskulárneho systému a jeho regulácií vo včasnom postnatálnom období v značnej miere závisí od zrelosti novorodenca. Cieľom práce bolo zistiť vzťah medzi kardiovaskulárnymi parametrami (frekvenciou srdca a jej variabilitou, pulzovým intervalom, systémovým tlakom krvi a parametrami odrážajúcimi intrauterinný a postnatálny vývoj a rast (gestačný vek, postkoncepčný vek, pôrodná a aktuálna hmotnosť) v skupine nedonosených detí v prvých týždňoch života. Metodika: U 43 nedonosených detí rôzneho gestačného veku, pôrodnej a aktuálnej hmotnosti bol v priemernom postkoncepčnom veku 34,6 týždňa kontinuálne a neinvazívne registrovaný krvný tlak a frekvencia srdca. Tlak krvi bol kontinuálne registrovaný pomocou prístroja Portapres (FMS) počas 2–5 minút v pokoji za štandardných podmienok. U každého dieťaťa bol analyzovaný stacionárny segment záznamu obsahujúci štandardne 250 tep po tepu (beat-to-beat) hodnôt tlaku krvi. U 35 detí bola spektrálnou analýzou zisťovaná variabilita pulzových intervalov odrážajúca variabilitu frekvencie srdca (celkový spektrálny výkon a výkony vo vysokofrekvenčnej – HF a nízkofrekvenčnej – LF oblasti). Výsledky: Korelačnou analýzou testami (Pearsonov, resp. Spearmanov korelačný koeficient) boli zistené pozitívne korelácie medzi gestačným, postkoncepčným vekom, pôrodnou a aktuálnou hmotnosťou a priemernou dĺžkou pulzového intervalu (IBI), celkovým spektrálnym výkonom variability pulzových intervalov (total power), ako aj spektrálnymi výkonmi v LF a HF pásme, a priemernou hodnotou diastolického i stredného tlaku krvi. Signifikantná negatívna korelácia bola medzi uvedenými anamnestickými parametrami a priemernou frekvenciou srdca a frekvenciou dýchania. Záver: U nedonosených novorodencov s vyšším gestačným a postkoncepčným vekom, pôrodnou a aktuálnou hmotnosťou sme zaznamenali vyšší celkový spektrálny výkon variability frekvencie srdca, nižšiu priemernú frekvenciu srdca a vyšší stredný a diastolický tlak krvi. Tieto zmeny a zistené závislosti poukazujú na zvyšujúci sa vplyv baroreflexov a postupné dozrievanie regulácie kardiovaskulárneho systému autonómnym nervovým systémom nedonosených novorodencov.

Relationships between the values of heart rate variability and blood pressure and parameters of growth and development in premature infants Introduction: The dynamics of the development of the cardiovascular system in the early postnatal period also depends on the maturity of the newborn. The aim of the study was to determine the relationships between cardiovascular parameters – heart rate variability, its components (LF, HF), pulse intervals (interbeat intervals – IBI), heart rate, systemic blood pressure and parameters reflecting development and growth – gestational age, postconceptional age, birth and actual weight in the group of premature babies in the first weeks of life. Methods: In 43 premature infants of various gestational ages, birth and actual weights, at a mean postconception age of 34.6 weeks, blood pressure and heart rate were continuously and non-invasively recorded. Blood pressure was recorded continuously for 2–5 minutes under standard conditions using a Portapres device (FMS). For each child, a stationary segment of the record containing 250 beat-to-beat blood pressure values was analyzed. The variability of interbeat intervals was determined by spectral analysis (total power, powers in high-frequency and low-frequency bands) in 35 children. Results: Correlation tests (Pearson´s and Spearman´s) revealed positive correlations between gestational, postconceptional age, birth and actual weight and mean value of pulse intervals (IBI), spectral total power of the IBI variability, as well as spectral powers in HF and LF bands, and diastolic and mean blood pressure. There was a significant negative correlation between the ages and weights and mean heart and respiratory rate. Conclusion: Preterm infants with higher gestational and postconceptional age, birth and actual weight have higher total power of heart rate variability.This is not only a consequence of the increase in spectral power in the HF band, but also in the LF band, which through the activities of the sympathetic and parasympathetic systems reflects mainly baroreflex activity. Together, the mean heart rate is lower and blood pressure, diastolic and mean are higher. The identified relationships point to the increasing baroreflex sensitivity and to the maturation of regulatory circuits of the cardiovascular system in premature infants.

• Klíčová slova
• variabilita srdeční frekvence,
• MeSH
• baroreflex MeSH
• klinická studie jako téma MeSH
• krevní tlak MeSH
• lidé MeSH
• novorozenec nedonošený * fyziologie   MeSH
• novorozenec MeSH
• srdeční frekvence MeSH
• Check Tag
• lidé MeSH
• novorozenec MeSH
• Publikační typ
• práce podpořená grantem MeSH

Fototerapia je najčastejšou terapeutickou intervenciou na novorodeneckých oddeleniach počas prvých dní života. Priaznivý vplyv svetla na zníženie hladiny sérového bilirubínu prvýkrát popísali Cremer a spol. v päťdesiatych rokoch minulého storočia. Od tých čias sa fototerapia efektívne využíva v liečbe významnej hyperbilirubinémie a dokázala takmer úplne eliminovať výmennú transfúziu. Fototerapia novorodencov je neinvazívnou metódou, no popri poklese koncentrácie bilirubínu ovplyvňuje aj niektoré ďalšie funkcie: perfúziu orgánov, najmä kože, periférnu vaskulárnu rezistenciu, distribúciu krvného prietoku, činnosť srdca, systémový tlak krvi, ako aj dýchanie. Vedľajšou zložkou aplikovaného svetla je určitý prílev tepla, ktoré ohrieva povrch tela. Vzniká tak nebezpečenstvo exogénneho prehriatia a zvýšenej straty vody kožou. V práci sme analyzovali vplyv fototerapie na tlak krvi a ďalšie parametre, ako sú frekvencia srdca, frekvencia dýchania, kyslíková saturácia, kožná a rektálna teplota. Pri porovnaní kontrolného súboru (n = 20) s pacientami s hyperbilirubinémiou a fototerapiou (n = 20) boli zistené významné zmeny sledovaných parametrov. Systolický, stredný aj diastolický tlak krvi významne klesol už po 1. hodine fototerapie (p = 0,001; p = 0,000; p = 0,001), na konci 2. hodiny fototerapie bol pokles ešte výraznejší (p = 0,002; p = 0,000; p = 0,003). Počas fototera-pie sa zvyšovala aj frekvencia akcie srdca a to už po 1. hodine, ešte výraznejšie na konci 2. hodiny fototerapie (p = 0,008; p = 0,002), taktiež stúpala aj frekvencia dýchania (p = 0,033; p = 0,015). Uvedené zmeny boli sprevádzané zvýšením kožnej i centrálnej (rektálnej) teploty. Z predkladaných výsledkov vyplýva, že počas fototerapie novorodencov dochádza k zmenám niektorých fyziologických parametrov. Dôsledné sledovanie vitálnych funkcií by preto malo byť samozrejmou súčasťou starostlivosti o novorodenca počas liečby modrým svetlom.

Phototherapy is the most frequent therapeutic intervention in neonatal wards during the first days of life. The beneficial effect of light on decreasing serum bilirubin level was first described by Cremer and colleagues in the 1950s. Since then, phototherapy has been used effectively in the treatment of severe hyperbilirubinaemia and has almost completely eliminated exchange transfusion. Phototherapy is a non-invasive method, but, in addition to decreasing bilirubin levels, it may affect some other function, e.g. organ perfusion, especially in skin, peripheral vascular resistance, blood flow distribution, heart frequency, systemic blood pressure and breathing. The next component of applied light is a certain influx of heat that warms the body surface up. There is a risk of exogenous overheating and increased water loss by skin. We analyzed the effect of phototherapy on blood pressure and other parameters such as heart rate, respiratory rate, oxygen saturation, skin and rectal temperature. Comparison of control group (n=20) with patients with hyperbilirubinaemia and phototherapy (n=20) showed significant changes in some monitored parameters. Systolic, mean and diastolic blood pressure decreased significantly after the first hour of phototherapy (p=0.001; p=0.000; p=0.001), while at the end of the 2nd hour of phototherapy the drop was even more pronounced (p=0.002; p=0.000; p=0.003). During phototherapy, heart rate increased after 1 hour, even more significantly at the end of the 2nd hour of phototherapy (p=0.008; p=0.002), the respiratory rate also increased (p=0.033; p=0.015). These changes were accompanied by increasing skin and central (rectal) temperature. Based on the results, there are changes in some physiological parameters during phototherapy in newborns. Consistent monitoring of vital signs should therefore be an obvious part of care of the newborn during the treatment with blue light.

• MeSH
• fototerapie * škodlivé účinky   MeSH
• hyperbilirubinemie * terapie   MeSH
• krevní tlak účinky záření   MeSH
• lidé MeSH
• měření krevního tlaku MeSH
• novorozenec MeSH
• Check Tag
• lidé MeSH
• novorozenec MeSH
• Publikační typ
• práce podpořená grantem MeSH

Ventilation related heart rate oscillations - respiratory sinus arrhythmia (RSA) - originate in human from several mechanisms. Two most important of them - the central mechanism (direct communication between respiratory and cardiomotor centers), and the peripheral mechanism (ventilation-associated blood pressure changes transferred to heart rate via baroreflex) have been described in previous studies. The major aim of this study was to compare the importance of these mechanisms in the generation of RSA non-invasively during various states by quantifying the strength of the directed interactions between heart rate, systolic blood pressure and respiratory volume signals. Seventy-eight healthy volunteers (32 male, age range: 16.02-25.77 years, median age: 18.57 years) participated in this study. The strength of mutual interconnections among the spontaneous beat-to-beat oscillations of systolic blood pressure (SBP), R-R interval (RR signal) and respiration (volume changes - RESP signal) was quantified during supine rest, orthostatic challenge (head-up tilt, HUT) and cognitive load (mental arithmetics, MA) using bivariate and trivariate measures of cardio-respiratory information transfer to separate baroreflex and nonbaroreflex (central) mechanisms. Our results indicate that both basic mechanisms take part in RSA generation in the intact cardiorespiratory control of human subjects. During orthostatic and mental challenges baroreflex based peripheral mechanism becomes more important.

• MeSH
• baroreflex fyziologie   MeSH
• dospělí MeSH
• elektrokardiografie metody   MeSH
• fotopletysmografie metody   MeSH
• krevní tlak fyziologie   MeSH
• lidé MeSH
• mladiství MeSH
• mladý dospělý MeSH
• respirační sinusová arytmie fyziologie   MeSH
• srdeční frekvence fyziologie   MeSH
• Check Tag
• dospělí MeSH
• lidé MeSH
• mladiství MeSH
• mladý dospělý MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH

In previous studies, one of the systolic time intervals - preejection period (PEP) - was used as an index of sympathetic activity reflecting the cardiac contractility. However, PEP could be also influenced by several other cardiovascular variables including preload, afterload and diastolic blood pressure (DBP). The aim of this study was to assess the behavior of the PEP together with other potentially confounding cardiovascular system characteristics in healthy humans during mental and orthostatic stress (head-up tilt test - HUT). Forty-nine healthy volunteers (28 females, 21 males, mean age 18.6 years (SD=1.8 years)) participated in the study. We recorded finger arterial blood pressure by volume-clamp method (Finometer Pro, FMS, Netherlands), PEP, thoracic fluid content (TFC) - a measure of preload, and cardiac output (CO) by impedance cardiography (CardioScreen® 2000, Medis, Germany). Systemic vascular resistance (SVR) - a measure of afterload - was calculated as a ratio of mean arterial pressure and CO. We observed that during HUT, an expected decrease in TFC was accompanied by an increase of PEP, an increase of SVR and no significant change in DBP. During mental stress, we observed a decrease of PEP and an increase of TFC, SVR and DBP. Correlating a change in assessed measures (delta values) between mental stress and previous supine rest, we found that deltaPEP correlated negatively with deltaCO and positively with deltaSVR. In orthostasis, no significant correlation between deltaPEP and deltaDBP, deltaTFC, deltaCO, deltaMBP or deltaSVR was found. We conclude that despite an expected increase of sympathetic activity during both challenges, PEP behaved differently indicating an effect of other confounding factors. To interpret PEP values properly, we recommend simultaneously to measure other variables influencing this cardiovascular measure.

• MeSH
• krevní tlak fyziologie   MeSH
• lidé MeSH
• minutový srdeční výdej fyziologie   MeSH
• mladiství MeSH
• mladý dospělý MeSH
• psychický stres patofyziologie   psychologie   MeSH
• srdeční frekvence fyziologie   MeSH
• sympatický nervový systém fyziologie   MeSH
• tepový objem fyziologie   MeSH
• test na nakloněné rovině metody   MeSH
• Check Tag
• lidé MeSH
• mladiství MeSH
• mladý dospělý MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH

At present, there are insufficient information about baroreflex sensitivity (BRS) and factors that determine BRS in premature newborns. The objective of this study was to determine the relationship between BRS and the characteristics that reflecting the intrauterine development (gestational age and birth weight), as well as postnatal development (postconception age and the actual weight of the child at the time of measurement). We examined 57 premature infants, who were divided into groups according to gestational age and postconception age as well as birth weight, and weight at the time of measurement. Continuous and noninvasive registration of peripheral blood pressure (BP) was performed in every child within 2-5 min under standard conditions using a Portapres (FMS) device. The results showed a close correlation of baroreflex sensitivity, heart rate and respiratory rate with gestational age, postconception age, birth weight and actual weight at the time of measurement premature newborns. An increase in the characteristics (ages and weights) resulted in increased BRS and diastolic arterial pressure (DAP), and in decreased heart and respiratory rates. Baroreflex sensitivity in the first week was in the group of very premature newborns the lowest (4.11 ms/mmHg) and in the light premature newborns was almost double (8.12 ms/mmHg). BRS increases gradually in relation to postnatal (chronological) and to postconception age as well as to birth and actual weight. The multifactor analysis of BRS identified birth weight and postconception age as the best BRS predictors. The two independent variables together explained 40 % of interindividual BRS variability.

• MeSH
• baroreflex fyziologie   MeSH
• gestační stáří * MeSH
• krevní tlak fyziologie   MeSH
• lidé MeSH
• měření krevního tlaku metody   MeSH
• novorozenec nedonošený fyziologie   MeSH
• novorozenec MeSH
• porodní hmotnost fyziologie   MeSH
• srdeční frekvence fyziologie   MeSH
• Check Tag
• lidé MeSH
• mužské pohlaví MeSH
• novorozenec MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH

Systolic blood pressure (SBP) changes control the cardiac inter-beat intervals (IBI) duration via baroreflex. Conversely, SBP is influenced by IBI via non-baroreflex mechanisms. Both causal pathways (feedback - baroreflex and feedforward - non-baroreflex) form a closed loop of the SBP - IBI interaction. The aim of this study was to assess the age-related changes in the IBI - SBP interaction. We have non-invasively recorded resting beat-to-beat SBP and IBI in 335 healthy subjects of different age, ranging from 11 to 23 years. Using a linear autoregressive bivariate model we obtained gain (Gain(SBP,IBI), used traditionally as baroreflex sensitivity) and coherence (Coh(SBP,IBI)) of the SBP-IBI interaction and causal gain and coherence in baroreflex (Gain(SBP->IBI), Coh(SBP->IBI) and coherence in non-baroreflex (Coh(IBI->SBP)) directions separately. A non-linear approach was used for causal coupling indices evaluation (C(SBP->IBI), C(IBI->SBP)) quantifying the amount of information transferred between signals. We performed a correlation to age analysis of all measures. Coh(IBI->SBP) and C(IBI->SBP) were higher than Coh(SBP->IBI) and C(SBP->IBI), respectively. Gain(SBP,IBI) increased and Coh(SBP->IBI) decreased with age. The coupling indices did not correlate with age. We conclude that the feedforward influence dominated at rest. The increase of Gain(SBP,IBI) with age was not found in the closed loop model. A decrease of Coh(SBP->IBI) could be related to a change in the cardiovascular control system complexity during maturation.

• MeSH
• baroreflex * MeSH
• dítě MeSH
• krevní tlak * MeSH
• lidé MeSH
• mladiství MeSH
• mladý dospělý MeSH
• srdce fyziologie   MeSH
• systola MeSH
• vývoj mladistvých * MeSH
• Check Tag
• dítě MeSH
• lidé MeSH
• mladiství MeSH
• mladý dospělý MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH