Noninvasive assessment of endothelial function and ST segment changes during exercise testing in coronary artery disease

Endothelial function (EF) plays an important role in the onset and clinical course of atherosclerosis, although its relationship with the presence and extent of coronary artery disease (CAD) has not been well defined. We evaluated EF and the ST segment response to an exercise test in patients with a broad spectrum of CAD defined by coronary angiography. Sixty-two patients submitted to diagnostic catheterization for the evaluation of chest pain or ischemia in a provocative test were divided into three groups according to the presence and severity of atherosclerotic lesions (AL): group 1: normal coronaries (N = 19); group 2: CAD with AL <70% (N = 17); group 3: CAD with AL ≥70% (N = 26). EF was evaluated by the percentage of flow-mediated dilatation (%FMD) in the brachial artery during reactive hyperemia induced by occlusion of the forearm with a pneumatic cuff for 5 min. Fifty-four patients were subjected to an exercise test. Gender and age were not significantly correlated with %FMD. EF was markedly reduced in both groups with CAD (76.5 and 73.1% vs 31.6% in group 1) and a higher frequency of ischemic alterations in the ST segment (70.8%) was observed in the group with obstructive CAD with AL ≥70% during the exercise test. Endothelial dysfunction was observed in patients with CAD, irrespective of the severity of injury. A significantly higher frequency of ischemic alterations in the ST segment was observed in the group with obstructive CAD. EF and exercise ECG differed among the three groups and may provide complementary information for the assessment of CAD.

An improved in vivo method for atrioventricular node ablation via thoracotomy

The atrioventricular (AV) node is permanently damaged in approximately 3% of congenital heart surgery operations, requiring implantation of a permanent pacemaker. Improvements in pacemaker design and in alternative treatment modalities require an effective in vivo model of complete heart block (CHB) before testing can be performed in humans. Such a model should enable accurate, reliable, and detectable induction of the surgical pathology. Through our laboratory’s efforts in developing a tissue engineering therapy for CHB, we describe here an improved in vivo model for inducing chronic AV block. The method employs a right thoracotomy in the adult rabbit, from which the right atrial appendage may be retracted to expose an access channel for the AV node. A novel injection device was designed, which both physically restricts needle depth and provides electrical information via electrocardiogram interface. This combination of features provides real-time guidance to the researcher for confirming contact with the AV node, and documents its ablation upon formalin injection. While all animals tested could be induced to acute AV block, those with ECG guidance were more likely to maintain chronic heart block >12 h. Our model enables the researcher to reproduce both CHB and the associated peripheral fibrosis that would be present in an open congenital heart surgery, and which would inevitably impact the design and utility of a tissue engineered AV node replacement.

Human umbilical cord blood cells in infarcted rats

Therapy with bone marrow-derived cells has been used in ischemic patients with reported success. The aim of this study was to determine the therapeutic efficacy of fresh and frozen human umbilical cord blood cells (hUCB) in Wistar rats submitted to permanent occlusion of the left coronary artery. Three hours after myocardial infarction, 2 x 10(7) hUCB cells or vehicle were administered by intramyocardial injection. The animals were divided into five groups: control (N = 10), sham operated (N = 10), infarcted that received vehicle (N = 9), infarcted treated with cryopreserved hUCB (N = 7), and infarcted treated with fresh hUCB (N = 5). Cardiac function was evaluated by electrocardiogram (ECG) and echocardiogram (ECHO) before cell therapy, and by ECG, ECHO, cardiopulmonary test, and left ventricular pressure measurements 3 weeks later. After 3 weeks, both groups treated with hUCB still had Q wave present in L1, âQRS >90° and reduced shortening fraction (less than 50%). In addition, cardiac indexes of left ventricular contractility and relaxation were 5484 ± 875 and -4032 ± 643 mmHg (cryopreserved hUCB) and 4585 ± 955 and -2862 ± 590 mmHg (fresh hUCB), respectively. These values were not statistically different from those of saline-treated animals. Cardiopulmonary exercise test profile was typical of infarcted hearts; exercise time was about 14 min and maximal VO2 was 24.77 ± 5.00 mL·kg-1·min-1. These data show that hUCB therapy did not improve the cardiac function of infarcted animals or prevent cardiac remodeling.

Reproducibility of heart rate variability parameters measured in healthy subjects at rest and after a postural change maneuver

Heart rate variability (HRV) provides important information about cardiac autonomic modulation. Since it is a noninvasive and inexpensive method, HRV has been used to evaluate several parameters of cardiovascular health. However, the internal reproducibility of this method has been challenged in some studies. Our aim was to determine the intra-individual reproducibility of HRV parameters in short-term recordings obtained in supine and orthostatic positions. Electrocardiographic (ECG) recordings were obtained from 30 healthy subjects (20-49 years, 14 men) using a digital apparatus (sampling ratio = 250 Hz). ECG was recorded for 10 min in the supine position and for 10 min in the orthostatic position. The procedure was repeated 2-3 h later. Time and frequency domain analyses were performed. Frequency domain included low (LF, 0.04-0.15 Hz) and high frequency (HF, 0.15-0.4 Hz) bands. Power spectral analysis was performed by the autoregressive method and model order was set at 16. Intra-subject agreement was assessed by linear regression analysis, test of difference in variances and limits of agreement. Most HRV measures (pNN50, RMSSD, LF, HF, and LF/HF ratio) were reproducible independent of body position. Better correlation indexes (r > 0.6) were obtained in the orthostatic position. Bland-Altman plots revealed that most values were inside the agreement limits, indicating concordance between measures. Only SDNN and NNv in the supine position were not reproducible. Our results showed reproducibility of HRV parameters when recorded in the same individual with a short time between two exams. The increased sympathetic activity occurring in the orthostatic position probably facilitates reproducibility of the HRV indexes.

Induction of chagasic-like arrhythmias in the isolated beating hearts of healthy rats perfused with Trypanosoma cruzi-conditioned medium

Chagas' myocardiopathy, caused by the intracellular protozoan Trypanosoma cruzi, is characterized by microvascular alterations, heart failure and arrhythmias. Ischemia and arrythmogenesis have been attributed to proteins shed by the parasite, although this has not been fully demonstrated. The aim of the present investigation was to study the effect of substances shed by T. cruzi on ischemia/reperfusion-induced arrhythmias. We performed a triple ischemia-reperfusion (I/R) protocol whereby the isolated beating rat hearts were perfused with either Vero-control or Vero T. cruzi-infected conditioned medium during the different stages of ischemia and subsequently reperfused with Tyrode's solution. ECG and heart rate were recorded during the entire experiment. We observed that triple I/R-induced bradycardia was associated with the generation of auricular-ventricular blockade during ischemia and non-sustained nodal and ventricular tachycardia during reperfusion. Interestingly, perfusion with Vero-infected medium produced a delay in the reperfusion-induced recovery of heart rate, increased the frequency of tachycardic events and induced ventricular fibrillation. These results suggest that the presence of parasite-shed substances in conditioned media enhances the arrhythmogenic effects that occur during the I/R protocol.

Utility of a novel risk score for prediction of ventricular tachycardia and cardiac death in chronic Chagas disease - the SEARCH-RIO study

The SEARCH-RIO study prospectively investigated electrocardiogram (ECG)-derived variables in chronic Chagas disease (CCD) as predictors of cardiac death and new onset ventricular tachycardia (VT). Cardiac arrhythmia is a major cause of death in CCD, and electrical markers may play a significant role in risk stratification. One hundred clinically stable outpatients with CCD were enrolled in this study. They initially underwent a 12-lead resting ECG, signal-averaged ECG, and 24-h ambulatory ECG. Abnormal Q-waves, filtered QRS duration, intraventricular electrical transients (IVET), 24-h standard deviation of normal RR intervals (SDNN), and VT were assessed. Echocardiograms assessed left ventricular ejection fraction. Predictors of cardiac death and new onset VT were identified in a Cox proportional hazard model. During a mean follow-up of 95.3 months, 36 patients had adverse events: 22 new onset VT (mean±SD, 18.4±4‰/year) and 20 deaths (26.4±1.8‰/year). In multivariate analysis, only Q-wave (hazard ratio, HR=6.7; P<0.001), VT (HR=5.3; P<0.001), SDNN<100 ms (HR=4.0; P=0.006), and IVET+ (HR=3.0; P=0.04) were independent predictors of the composite endpoint of cardiac death and new onset VT. A prognostic score was developed by weighting points proportional to beta coefficients and summing-up: Q-wave=2; VT=2; SDNN<100 ms=1; IVET+=1. Receiver operating characteristic curve analysis optimized the cutoff value at >1. In 10,000 bootstraps, the C-statistic of this novel score was non-inferior to a previously validated (Rassi) score (0.89±0.03 and 0.80±0.05, respectively; test for non-inferiority: P<0.001). In CCD, surface ECG-derived variables are predictors of cardiac death and new onset VT.

Differentiating origins of outflow tract ventricular arrhythmias: a comparison of three different electrocardiographic algorithms

Our objective is to evaluate the accuracy of three algorithms in differentiating the origins of outflow tract ventricular arrhythmias (OTVAs). This study involved 110 consecutive patients with OTVAs for whom a standard 12-lead surface electrocardiogram (ECG) showed typical left bundle branch block morphology with an inferior axis. All the ECG tracings were retrospectively analyzed using the following three recently published ECG algorithms: 1) the transitional zone (TZ) index, 2) the V2 transition ratio, and 3) V2 R wave duration and R/S wave amplitude indices. Considering all patients, the V2 transition ratio had the highest sensitivity (92.3%), while the R wave duration and R/S wave amplitude indices in V2 had the highest specificity (93.9%). The latter finding had a maximal area under the ROC curve of 0.925. In patients with left ventricular (LV) rotation, the V2 transition ratio had the highest sensitivity (94.1%), while the R wave duration and R/S wave amplitude indices in V2 had the highest specificity (87.5%). The former finding had a maximal area under the ROC curve of 0.892. All three published ECG algorithms are effective in differentiating the origin of OTVAs, while the V2 transition ratio, and the V2 R wave duration and R/S wave amplitude indices are the most sensitive and specific algorithms, respectively. Amongst all of the patients, the V2 R wave duration and R/S wave amplitude algorithm had the maximal area under the ROC curve, but in patients with LV rotation the V2 transition ratio algorithm had the maximum area under the ROC curve.

Pesquisa de doença aterosclerótica multiarterial em pacientes hipertensos com estenose de artéria renal

INTRODUÇÃO: A detecção de estenose de artéria renal em pacientes hipertensos pode ser um sinal de aterosclerose arterial sistêmica. OBJETIVOS: Identificar e caracterizar do ponto de vista clínico e epidemiológico os pacientes hipertensos com estenose de artéria renal, avaliando fatores de risco cardiovascular e presença de doença aterosclerótica multiarterial sintomática. MÉTODO: Foram selecionados os pacientes hipertensos atendidos no ambulatório de Nefrologia da Universidade Federal do Triângulo Mineiro (UFTM) entre 2000-2010, com diagnóstico de estenose de artéria renal de etiologia aterosclerótica. Avaliaram-se dados epidemiológicos (gênero, idade, etnia), fatores de risco cardiovascular (Diabetes Mellitus, hipercolesterolemia, hipertrigliceridemia, tabagismo, síndrome metabólica), informações relativas à hipertensão (tempo de diagnóstico, histórico familiar, número de medicamentos utilizados), eventos cardiovasculares prévios (infarto agudo do miocárdio, acidente vascular encefálico isquêmico, doença arterial periférica). Estratificaram-se os níveis pressóricos, risco cardiovascular global e escore Framingham. RESULTADOS: Casuística de 30 pacientes, maioria feminina (73,3%), média de idade de 66 anos, 86,67% brancos. Tempo médio de HAS de 19,94 anos, 89,28% sem histórico familiar, 13,8% com diabetes, 65,51% tabagistas, 17,25% com hipertrigliceridemia, 62,06% com hipercolesterolemia e 66,7% com síndrome metabólica. Número médio de medicamentos em uso: 3,26. Estenose de artéria renal predominante à direita quando isoladamente (46,7%) e em terço proximal (56,7%). Creatinina elevada em 40% dos pacientes. Quanto ao estágio de hipertensão, maioria estágio 2 (47%) e 73,3% com risco cardiovascular global alto. Escore Framingham Médio de 13%. 66,7% apresentavam doença aterosclerótica em outro sítio, sendo coronariano o principal (53,3%). CONCLUSÃO: A correlação mais comum foi com o infarto agudo do miocárdio, o que implica na busca do comprometimento coronário quando do diagnóstico de estenose de artéria renal em pacientes hipertensos, para tentar evitar danos futuros ao paciente.

Fatores de risco para lesão renal aguda em pacientes com trauma grave e seus efeitos na mortalidade

Os estudos que relacionaram lesão renal aguda (LRA) e trauma surgiram durante a Segunda Guerra Mundial e, desde então, tem havido progressiva evolução dos cuidados para a prevenção da LRA. Entretanto, a determinação dos fatores de risco para o desenvolvimento de LRA pós-trauma permanece crucial e pode ajudar a reduzir esta complicação. OBJETIVO: Este estudo tem como objetivo identificar os fatores de risco para o desenvolvimento de LRA em pacientes com trauma grave e sua influência na mortalidade. Trata-se de um estudo retrospectivo com 75 pacientes incluídos por apresentarem trauma grave; seis foram excluídos por terem chegado ao hospital sem condições de ressuscitação. MÉTODO: As variáveis estudadas foram: idade, sexo, gravidade do trauma de acordo com Injury Severity Score (ISS) e Escala de Coma de Glasgow (ECG), mecanismo de trauma, pressão arterial média na admissão, reposição volêmica nas primeiras 24h, níveis séricos de creatinina, uso de antibióticos nefrotóxicos, tempo de internação, necessidade de internação em UTI e mortalidade. RESULTADOS: A prevalência de LRA em traumatizados graves foi de 17,3%, sendo que os fatores associados à IRA nessa amostra foram TCE, ECG < 10. A mortalidade, o tempo de internação e a necessidade de UTI foram significativamente maiores nos pacientes que desenvolveram LRA. CONCLUSÕES: A identificação desses fatores de risco é de suma importância para a formulação de estratégias de atendimento aos pacientes vítimas de trauma grave, visando à prevenção da lesão renal aguda e da elevada mortalidade.

Prevalência e fatores associados à doença renal crônica em pacientes internados em um hospital universitário na cidade de São Paulo, SP, Brasil

Introdução: A doença renal crônica (DRC) constitui importante problema de saúde pública mundial. Contudo, dados sobre prevalência e comorbidades são escassos no Brasil. Objetivo: Identificar a prevalência e fatores associados à DRC em pacientes internados em um hospital universitário. Métodos: Foram selecionados, aleatoriamente, 826 prontuários de pacientes internados em clínica médica. A DRC foi baseada no diagnóstico médico descrito no prontuário. Foram coletadas informações clínico-demográficas e feitas comparações entre pacientes com e sem DRC. Resultados: A prevalência de DRC foi 12,7%. Os pacientes com DRC se distinguiram daqueles sem a doença (p < 0,05) por terem companheiro (59,8% vs. 47,3%); idade mais elevada (65,8 ± 15,6 vs. 55,3 ± 18,9 anos); mais comorbidades como hipertensão arterial (75,2% vs. 46,3%), diabetes (49,5% vs. 22,4%), dislipidemia (23,8% vs. 14,9%), infarto do miocárdio (14,3% vs. 6,0%) e insuficiência cardíaca congestiva (18,1% vs. 4,3%); maior período de internação (11 (8-18) vs. 9 (6-12) dias) e; mais óbitos (12,4% vs. 1,4%). A análise de regressão logística indicou associação independente (OR, odds ratio; IC, intervalo de confiança de 95%) da DRC com idade (OR 1,019, IC 1,003-1,036), hipertensão arterial (OR 2,032, IC 1,128-3,660), diabetes (OR 2,097, IC 1,232-3,570) e insuficiência cardíaca congestiva (OR 2,665, IC 1,173-6,056). Conclusão: A prevalência de DRC em pacientes internados em clínica médica foi alta, sendo estes pacientes clinicamente mais complexos, visto apresentarem idade mais elevada e maior número de comorbidades, refletindo em maior risco de óbito durante internação hospitalar.

Toward a Reliable Classifier For Arrhythmia Diagnosis

Illnesses related to the heart are one of the major reasons for death all over the world causing many people to lose their lives in last decades. The good news is that many of those sicknesses are preventable if they are spotted in early stages. On the other hand, the number of the doctors are much lower than the number of patients. This will makes the auto diagnosing of diseases even more and more essential for humans today. Furthermore, when it comes to the diagnosing methods and algorithms, the current state of the art is lacking a comprehensive study on the comparison between different diagnosis solutions. Not having a single valid diagnosing solution has increased the confusion among scholars and made it harder for them to take further steps. This master thesis will address the issue of reliable diagnosing algorithm. We investigate ECG signals and the relation between different diseases and the heart’s electrical activity. Also, we will discuss the necessary steps needed for auto diagnosing the heart diseases including the literatures discussing the topic. The main goal of this master thesis is to find a single reliable diagnosing algorithm and quest for the best classifier to date for heart related sicknesses. Five most suited and most well-known classifiers, such as KNN, CART, MLP, Adaboost and SVM, have been investigated. To have a fair comparison, the ex-periment condition is kept the same for all classification methods. The UCI repository arrhythmia dataset will be used and the data will not be preprocessed. The experiment results indicates that AdaBoost noticeably classifies different diseases with a considera-bly better accuracy.

Sydämen eteisvärinän tunnistaminen matkapuhelimen kiihtyvyysanturilla

Yli 140 miljoonaa ihmistä kärsii kroonisesta eteisvärinästä. Monilla ihmisillä on eteisvärinää, vaikkeivat siitä itse tiedä. Hoito on yksinkertainen, mutta hoidon piiriin eivät päädy kaikki yksinkertaisten seulontamenettelyjen tuloksena. Elektrokardiogrammi (EKG) sydämen toimintojen tunnistusmenetelmänä on tällä hetkellä yleisin vaihtoehto eteisvärinän seulontaan. EKG-laitteet ovat arvokkaita ja haasteellisia yksittäisen käyttäjän arkielämän kannalta. Vaihtoehtoinen sydämen monitorointimenetelmä on ballistokardiografinen (BKG) mittaus. EKG:n ja BKG:n ominaisia piirteitä käydään lävitse ja vertaillaan vahvuuksia sekä heikkouksia näiden kahden mittausmenetelmän välillä. BKG:ta on tutkittu jo pitkään, mutta mittaukseen soveltuvia tähän käyttökohteeseen varsinaisesti suunniteltuja laitteita ei ole paljoakaan tuotteistettu markkinoille asti. Työssä tutkitaan matkapuhelimen kiihtyvyysanturin soveltuvuutta BKG-mittauksen suorittamiseen. Tällä menetelmällä on mahdollista tuoda helposti sydänmonitori lähelle ihmisiä ja jokainen voi omalla matkapuhelimellaan tarkkailla sydämensä toimintaa. Diplomityössä selvitetään erilaisten markkinoilla olevien mobiililaitteiden soveltuvuutta kiihtyvyysanturitutkimukseen. Useampaa mallia koskevan selvitystyön tuloksena valitaan parhaiten toimiva vaihtoehto, jolla jatketaan tutkimusta suunnittelemalla mittausprosessi. Ensimmäisen vaiheen mittauksissa valitaan 20 perustervettä koehenkilöä tutkimukseen. Tutkimuksen tuloksena saadaan tutkimushypoteesin mukainen tulos ja sydämen lyönnit saadaan tunnistettua kaikilla koehenkilöillä. Ensimmäisen vaiheen aikana suoritetaan myös liikehäiriötutkimusta. Tässä suoritetaan yksinkertaiset käden, jalan ja pään liikkeiden vaikutuksen arvioinnit kiihtyvyysanturisignaaliin. Lisäksi selvitetään, miten puhuminen mittauksen aikana välittyy tutkimuslaitteeseen ja suoritetaan arvio siitä, miten tämä voidaan ottaa huomioon. Ensimmäisen vaiheen havaintojen perusteella jatkokehitetään mittausprosessia ja pyritään optimoimaan tätä, jotta laajempi otosjoukko on mahdollista saavuttaa mahdollisimman vähän aikaresursseja kuluttaen. Työssä valmistellaan laajemman, 1000 koehenkilöä sisältävän, toisen tutkimusvaiheen suoritusta. Diplomityön osana valmistellaan Varsinais-Suomen Sairaanhoitopiirin eettiselle toimikunnalle lausuntohakemus tutkimukselle. Hakemuksessa käsitellään laajasti tutkimuksen suorittamista eri osa-alueilla. Toisen vaiheen tuloksen noudattaessa tutkimushypoteesia, voidaan todeta matkapuhelimen kiihtyvyysanturin olevan soveluva menetelmä sydämen toiminnan tutkimiseen.

ERP and cardiovascular correlates of source memory discrimination in older and younger adults /

There is much evidence to support an age-related decline in source memory ability. However, the underlying mechanisms responsible for this decline are not well understood. The current study was carried out to determine the electrophysiological correlates of source memory discrimination in younger and older adults. Event-related potentials (ERPs) and continuous electrocardiographic (ECG) data were collected from younger (M= 21 years) and older (M= 71 years) adults during a source memory task. Older adults were more likely to make source memory errors for recently repeated, non-target words than were younger adults. Moreover, their ERP records for correct trials showed an increased amplitude in the late positive (LP) component (400-800 msec) for the most recently presented, non-target stimuli relative to the LP noted for target items. Younger adults showed an opposite pattern, with a large LP component for target items, and a much smaller LP component for the recently repeated non-target items. Computation of parasympathetic activity in the vagus nerve was performed on the ECG data (Porges, 1985). The resulting measure, vagal tone, was used as an index of physiological responsivity. The vagal tone index of physiological responsivity was negatively related to the LP amplitude for the most recently repeated, non-target words in both groups, after accounting for age effects. The ERP data support the hypothesis that the tendency to make source memory errors on the part of older adults is related to the ability to selectively control attentional processes during task performance. Furthermore, the relationship between vagal tone and ERP reactivity suggests that there is a physiological basis to the heightened reactivity measured in the LP response to recently repeated non-target items such that, under decreased physiological resources, there is an impairment in the ability to selectively inhibit bottom-up, stimulus based properties in favour of task-related goals in older adults. The inconsistency of these results with other explanatory models of source memory deficits is discussed. It is concluded that the data are consistent with a physiological reactivity model requiring inhibition of reactivity to irrelevant, but perceptually-fluent, stimuli.

The validation of heart rate variability in individuals with spinal cord injury

The current classification system for spinal cord injury (SCI) considers only somatic information and neglects autonomic damage after injiuy. Heart rate variability (HRV) has the potential to be a valuable measure of cardiac autonomic control after (SCI). Five individuals with tetraplegia and four able-bodied controls underwent 1 min continuous ECG recordings during rest, after Metoprolol administration (max dose=3x5mg) and after Atropine administration (0.02mg/kg) in both supine and 40° head-up tilt. After Metoprolol administration there was a 61.8% decrease in the LF:HF ratio in the SCI participants suggesting that the LF:HF ratio is a reflection of cardiac sympathetic outflow. After Atropine administration there was a 99.1% decrease in the HF power in the SCI participants suggesting that HF power is highly representative of cardiac parasympathetic outflow. There were no significant differences between the SCI and able-bodied participants. Thus, HRV measures are a valid index of cardiac autonomic control after SCI.

Autonomic regulation and blood pressure in children

Vagal baroreflex sensitivity (BRS) is a measure of short term blood pressure (BP) regulation through alterations in heart rate. Low BRS reflects impaired autonomic system regulation and has been found to be a surrogate marker for cardiovascular health. In particular, it has found to be associated with the pathogenesis of adult hypertension. However, only limited information exists as to the negative consequences of childhood BP on baroreflex function. The objective of this study was to investigate BRS in children with 2 different BP profiles while controlling for the effects of age, maturation, sex, and body composition. A preliminary subsample of 11-14 year-old children from the HBEAT (Heart Behavioural Environmental Assessment Team) Study was selected. The children were divided into 2 BP groups; high BP (HBP; 2:95tl1 percentile, n=21) and normal BP (NBP; <90th percentile, n=85). Following an initial 15 minutes of supine rest, 5 minutes of continuous beat-to-beat BP (Finapres) and RR interval (RRI) were recorded (standard ECG). Spectral indices were computed using Fast Fourier Transform and transfer function analysis was used to compute BRS. High frequency (HF) and low frequency (LF) power spectral areas were set to 0.15-0.4 Hz and 0.04-0.15 Hz, respectively. Body composition was measured using body mass index. After adjusting for body composition, maturation, age and sex ANCOV A results were as follows; LF and HF BRS, LF and HF RRI, and RRI total power were lower in the HBP versus NBP participants (p<0.05). As well, LF IHF SBP ratio was significantly higher in the HBP compared to the NBP group (p<0.05). The regression coefficients (unstandardized B) indicated that in changing groups (NBP to HBP) LF and HF BRS decreases by 4.04 and 6.18 ms/mmHg, respectively. Thus, as BP increases, BRS decreases. These data suggest that changes in autonomic activity occur in children who have HBP, regardless of age, sex, maturation, and body composition. Thus, despite their young age and relatively short amount of time having high BP compared with adults, these children are already demonstrating poor BP regulation and reduced cardiovagal activity. Given that childhood BP is associated with hypertension in adulthood, there is a growing concern in regards to the current cardiovascular health of our children and future adults.