Nízká senzitivita baroreflexu (BRS) se podílí na rozvoji hypertenze u dospělých. Předmětem studie je vyšetření BRS u dlouhodobě sledovaných mladistvých s cílem určit prognostickou hodnotu BRS u mladistvých pro vývoj esenciální hypertenze.; Low baroreflex sensitivity(BRS) play a role in the development of hypertension in adults.The aim of the study is to assess the prognostic value of BRS for the development of essential hypertension in adolescents.

• MeSH
• antracykliny terapeutické užití   toxicita   škodlivé účinky   MeSH
• baroreflex účinky léků   MeSH
• dítě MeSH
• hypertenze MeSH
• kardiovaskulární nemoci prevence a kontrola   MeSH
• kojenec MeSH
• měření krevního tlaku MeSH
• mladiství MeSH
• nádory terapie   MeSH
• Check Tag
• dítě MeSH
• kojenec MeSH
• mladiství MeSH

• Konspekt
• Lékařské vědy. Lékařství
• NLK Obory
• kardiologie
• onkologie
• farmacie a farmakologie
• NLK Publikační typ
• závěrečné zprávy o řešení grantu IGA MZ ČR

Riziko náhlé srdeční smrti nemocného po srdečním infarktu je mimo jiné ovlivněno úrovní vegetativního tonusu.Projekt řeší novou metodiku testování zesílení citlivosti tzv.baroreflexu a jeho porovnání s HRV,LP a Holterovským monitoringem.

• MeSH
• akutní nemoc MeSH
• baroreflex MeSH
• infarkt myokardu MeSH
• náhlá srdeční smrt MeSH

• Konspekt
• Patologie. Klinická medicína
• NLK Obory
• kardiologie
• angiologie
• NLK Publikační typ
• závěrečné zprávy o řešení grantu IGA MZ ČR

• MeSH
• anatomie MeSH
• fyziologie MeSH

• Konspekt
• Lékařské vědy. Lékařství
• NLK Obory
• anatomie
• fyziologie
• NLK Publikační typ
• učebnice vysokých škol

• MeSH
• krevní oběh fyziologie   MeSH
• spektrální analýza MeSH
• Publikační typ
• monografie MeSH

• Konspekt
• Patologie. Klinická medicína
• NLK Obory
• vnitřní lékařství
• kardiologie
• chemie, klinická chemie
• angiologie

The increased prevalence of obesity in children and its complications have led to a greater interest in studying baroreflex sensitivity (BRS) in children. This review of BRS in children and adolescents includes subtopics on: 1. Resting values of BRS and their reproducibility, 2. Genetics of BRS, 3. The role of a primarily low BRS and obesity in the development of hypertension, and 4. Association of diabetes mellitus, BRS, and obesity. The conclusions specific to this age follow from this review: 1. The mean heart rate (HR) influences the measurement of BRS. Since the mean HR decreases during adolescence, HR should be taken into account. 2. A genetic dependency of BRS was found. 3. Low BRS values may precede pathological blood-pressure elevation in children with white-coat hypertension. We hypothesize that low BRS plays an active role in the emergence of hypertension in youth. A contribution of obesity to the development of hypertension was also found. We hypothesize that both factors, a primarily low BRS and obesity, are partially independent risk factors for hypertension in youths. 4. In diabetics, a low BRS compared to healthy children can be associated with insulin resistance. A reversibility of the BRS values could be possible after weight loss.

• MeSH
• baroreflex genetika   fyziologie   MeSH
• diabetes mellitus genetika   patofyziologie   MeSH
• dítě MeSH
• dospělí MeSH
• hypertenze genetika   patofyziologie   MeSH
• lidé MeSH
• mladiství MeSH
• obezita genetika   patofyziologie   MeSH
• Check Tag
• dítě MeSH
• dospělí MeSH
• lidé MeSH
• mladiství MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy 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

The aim of this study was to obtain a detailed analysis of the relationship between the finger arterial compliance C [ml/mm Hg] and the arterial transmural pressure P(t) [mm Hg]. We constructed a dynamic plethysmograph enabling us to set up a constant pressure P(css) [mm Hg] and a superimposed fast pressure vibration in the finger cuff (equipped with a source of infra-red light and a photoelectric sensor for the measurement of arterial volume). P(css) could be set on the required time interval in steps ranging between 30 and 170 mm Hg, and on sinusoidal pressure oscillation with an amplitude P(ca) (2 mm Hg) and a frequency f (20, 25, 30, 35, 40 Hz). At the same time continuous blood pressure BP was measured on the adjacent finger (Portapres). We described the volume dependence of a unitary arterial length on the time-varying transmural pressure acting on the arterial wall (externally P(css)+P(ca).sin(2pif), internally BP) by a second-order differential equation for volume. This equation was linearized within a small range of selected BP. In the next step, a Fourier transform was applied to obtain the frequency characteristic in analytic form of a complex linear combination of frequency functions. While series of oscillations [P(ca), f] were applied for each P(css), the corresponding response of the plethysmogram was measured. Amplitude spectra were obtained to estimate coefficients of the frequency characteristic by regression analysis. We determined the absolute value: elastance E, and its inverse value: compliance (C=1/E). Then, C=C(P(t)) was acquired by applying sequences of oscillations for different P(css) (and thus P(t)) by the above-described procedure. This methodology will be used for the study of finger arterial compliance in different physiological and pathological conditions.

• MeSH
• arterie fyziologie   MeSH
• diagnostické techniky kardiovaskulární * přístrojové vybavení   MeSH
• krevní tlak MeSH
• lidé MeSH
• mladý dospělý MeSH
• modely kardiovaskulární MeSH
• pletysmografie metody   MeSH
• poddajnost MeSH
• prsty ruky MeSH
• senioři MeSH
• vibrace MeSH
• Check Tag
• lidé MeSH
• mladý dospělý MeSH
• mužské pohlaví MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Decreased baroreflex sensitivity is an early sign of autonomic dysfunction in patients with type-1 diabetes mellitus. We evaluated the repeatability of a mild baroreflex sensitivity decrease in diabetics with respect to their heart rate. Finger blood pressure was continuously recorded in 14 young diabetics without clinical signs of autonomic dysfunction and in 14 age-matched controls for 42 min. The recordings were divided into 3-min segments, and the mean inter-beat interval (IBI), baroreflex sensitivity in ms/mm Hg (BRS) and mHz/mm Hg (BRSf) were determined in each segment. These values fluctuated in each subject within 42 min and therefore coefficients of repeatability were calculated for all subjects. Diabetics compared with controls had a decreased mean BRS (p=0.05), a tendency to a shortened IBI (p=0.08), and a decreased BRSf (p=0.17). IBI correlated with BRS in diabetics (p=0.03); this correlation was at p=0.12 in the controls. BRSf was IBI independent (controls: p=0.81, diabetics: p=0.29). We conclude that BRS is partially dependent on mean IBI. Thus, BRS reflects not only an impairment of the quick baroreflex responses of IBI to blood pressure changes, but also a change of the tonic sympathetic and parasympathetic heart rate control. This is of significance during mild changes of BRS. Therefore, an examination of the BRSf index is highly recommended, because this examination improves the diagnostic value of the measurement, particularly in cases of early signs of autonomic dysfunction.

• MeSH
• baroreflex * MeSH
• diabetes mellitus 1. typu diagnóza   patofyziologie   MeSH
• krevní tlak MeSH
• lidé MeSH
• mladý dospělý MeSH
• nemoci autonomního nervového systému diagnóza   etiologie   patofyziologie   MeSH
• reprodukovatelnost výsledků MeSH
• senzitivita a specificita MeSH
• srdeční frekvence * MeSH
• Check Tag
• lidé MeSH
• mladý dospělý MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Baroreflex regulation of blood pressure primarily moderates its fluctuations and also affects mean blood pressure. Heart rate baroreflex sensitivity is described as changes of the inter-beat interval induced by a change of blood pres- sure of 1 mmHg (BRS). BRS is decreased in many cardiovascular diseases (hypertension, diabetes mellitus, obesity, cardiac failure, etc.). Decreased BRS in disposed individuals, especially after myocardial infarction, increases the risk of sudden cardiac death. Therefore, early diagnosis of BRS decrease gains in importance. This article describes dif- ferent methods of determination of baroreflex sensitivity. The methods are based on evaluation of the spontaneous fluctuation of heart rate and blood pressure (spectral, sequential or nonlinear methods), or of primary changes of blood pressure induced by a vasoactive substance or a physiological manoeuvre and corresponding changes of cardiac intervals (Valsalva manoeuvre, phenylephrine administration). Each method has its advantages and disadvantages resulting from a different difficulty of calculation or from inclusion of different deviations in the results, which are not directly linked with baroreflex. Baroreflex regulating total peripheral resistance is less described. A mathematical model of baroreflex blood pressure regulation by fluctuation of heart rate and peripheral resistance is presented in this paper.

• Klíčová slova
• autonomní regulace, citlivost baroreflexu, metody stanovení citlivosti baroreflexu, model baroreflexu,
• MeSH
• baroreflex * fyziologie   účinky léků   MeSH
• diagnostické techniky kardiovaskulární MeSH
• hypertenze diagnóza   krev   patofyziologie   MeSH
• klinické zkoušky jako téma MeSH
• lidé MeSH
• měření krevního tlaku * metody   využití   MeSH
• modely kardiovaskulární MeSH
• monitorování fyziologických funkcí dějiny   metody   trendy   využití   MeSH
• počítačové zpracování signálu MeSH
• prediktivní hodnota testů MeSH
• rychlost toku krve MeSH
• srdeční frekvence MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• práce podpořená grantem MeSH

In this study we tested whether joint evaluation of the frequency (f(cs)) at which maxima of power in the cross-spectra between the variability in systolic blood pressure and inter-beat intervals in the range of 0.06-0.12 Hz occur together with the quantification of baroreflex sensitivity (BRS) may improve early detection of autonomic dysfunction in type 1 diabetes mellitus (T1DM). We measured 14 T1DM patients (age 20.3-24.2 years, DM duration 10.4-14.2 years, without any signs of autonomic neuropathy) and 14 age-matched controls (Co). Finger arterial blood pressure was continuously recorded by Finapres for one hour. BRS and f(cs) were determined by the spectral method. Receiver-operating curves (ROC) were calculated for f(cs), BRS, and a combination of both factors determined as F(z)=1/(1+exp(-z)), z=3.09-0.013*BRS-0.027*f(cs). T1DM had significantly lower f(cs) than Co (T1DM: 88.8+/-6.7 vs. Co: 93.7+/-3.8 mHz; p<0.05), and a tendency towards lower BRS compared to Co (T1DM: 10.3+/-4.4 vs. Co: 14.6+/-7.1 ms/mm Hg; p=0.06). The ROC for Fz showed the highest sensitivity and specificity (71.4 % and 71.4 %) in comparison with BRS (64.3 % and 71.4 %) or f(cs) (64.3 % and 64.3 %). The presented method of evaluation of BRS and f(cs) forming an integrated factor Fz could provide further improvement in the risk stratification of diabetic patients.

• MeSH
• arteriální tlak fyziologie   MeSH
• baroreflex fyziologie   MeSH
• diabetes mellitus 1. typu patofyziologie   MeSH
• elektrokardiografie MeSH
• lidé MeSH
• měření krevního tlaku MeSH
• mladý dospělý MeSH
• srdeční frekvence fyziologie   MeSH
• Check Tag
• lidé MeSH
• mladý dospělý MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH