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The aim of this work was to obtain insights of the participation of the autonomic nervous system in different stages of calcific aortic valve disease (CAVD) by heart rate variability (HRV) analysis. Studying subjects with no valve impairments and CAVD patients, we also sought to quantify the independent contribution or explanatory capacity of the aortic valve echocardiographic parameters involved in the HRV changes caused by active standing using hierarchical partitioning models to consider other variables or potential confounders. We detected smaller adjustments of the cardiac autonomic response at active standing caused specifically by the aortic valve deterioration. The highest association (i.e., the highest percentage of independent exploratory capacity) was found between the aortic valve area and the active standing changes in the short-term HRV scaling exponent α1 (4.591%). The valve’s maximum pressure gradient echocardiographic parameter was present in most models assessed (in six out of eight models of HRV indices that included a valve parameter as an independent variable). Overall, our study provides insights with a wider perspective to explore and consider CAVD as a neurocardiovascular pathology. This pathology involves autonomic-driven compensatory mechanisms that seem generated by the aortic valve deterioration.

Aortic stenosis is a progressive heart valve disorder characterized by calcification of the leaflets. Heart rate variability (HRV) analysis has been proposed for assessing the heart response to autonomic activity, which is documented to be altered in different cardiac diseases. The objective of the study was to evaluate changes of HRV in patients with aortic stenosis by an active standing challenge. Twenty-two volunteers without alterations in the aortic valve (NAV) and twenty-five patients diagnosed with moderate and severe calcific aortic valve stenosis (AVS) participated in this cross-sectional study. Ten minute electrocardiograms were performed in a supine position and in active standing positions afterwards, to obtain temporal, spectral, and scaling HRV indices: mean value of all NN intervals (meanNN), low-frequency (LF) and high-frequency (HF) bands spectral power, and the short-term scaling indices (α1 and αsign1). The AVS group showed higher values of LF, LF/HF and αsign1 compared with the NAV group at supine position. These patients also expressed smaller changes in meanNN, LF, HF, LF/HF, α1, and αsign1 between positions. In conclusion, we confirmed from short-term recordings that patients with moderate and severe calcific AVS have a decreased cardiac parasympathetic supine response and that the dynamic of heart rate fluctuations is modified compared to NAV subjects, but we also evidenced that they manifest reduced autonomic adjustments caused by the active standing challenge.

Intradialytic hypotension occurs in 10&ndash, 30% of hemodialysis (HD) sessions. This phenomenon affects the cardiovascular system&rsquo, s functions, which are reflected in the activity of the autonomic nervous system (ANS). To indirectly assess the ANS during HD, we analyzed the mean R&ndash, R intervals and the spectral power of heart rate variability (HRV) from 20 end-stage renal disease patients divided into hypotensive and non-hypotensive groups. The spectrotemporal analysis was accomplished using short-time Fourier transform with 10 min epochs of HRV overlapping by 40%. The spectral power was divided into three segments according to high frequency, low frequency, and very low frequency bandwidths and averaged to fit quadratic regression models. The analysis of the mean R&ndash, R intervals showed significant differences between the groups (p = 0.029). The power variation over time was significant in each spectral band (p ≪ 0.05). The average power, maximum power, and time when the peak was reached differed for each band and between groups, showing the ability to correctly identify the decompensation of the ANS and discriminate between hypotensive and non-hypotensive patients. Additionally, the changes in the sympathovagal ratio were not significant and very scattered for the hypotensive group (p = 0.23) compared to the non-hypotensive group, where the changes were significant (p ≪ 0.05) and much less scattered.

The aim of this work was to evaluate the short-term fractal index (α1 ) of heart rate variability (HRV) in chronic renal failure (CRF) patients by identifying the effects of orthostatism and hemodialysis (HD), and by evaluating the correlation between α1 and the mean RR interval from sinus beats (meanNN). HRV time series were derived from ECG data of 19 CRF patients and 20 age-matched healthy subjects obtained at supine and orthostatic positions (lasting 5 min each). Data from CRF patients were collected before and after HD. α1 was calculated from each time series and compared by analysis of variance. Pearson's correlations between meanNN and α1 were calculated using the data from both positions by considering three groups: healthy subjects, CRF before HD and CRF after HD. At supine position, α1 of CRF patients after HD (1.17 ± 0.30) was larger (P

A high dietary sodium intake and a low potassium intake are associated with adverse cardiovascular health. Data on these nutrients consumption in Mexico is limited. The aim of this study was to assess sodium and potassium intake by 24 h urinary excretion in a clinically healthy Mexican population. We additionally explored their association with blood pressure.711 clinically healthy participants aged 20-50 years old recruited in the Tlalpan 2020 cohort from September 2014-December 2015, were included in this cross-sectional analysis. All participants provided a 24 h urine sample and underwent anthropometric, biochemical, and blood pressure evaluations. Univariate and multivariate linear regression analyses were used to assess the association of urinary sodium, potassium, and Na/K ratio with blood pressure.Mean (95% confidence interval [CI]) urinary sodium and potassium in the overall population was 3150.1 (3054.2-3246.0) mg/d and 1909.5 (1859.3-1959.6) mg/d, respectively. Overall, only 121 (17%) met the WHO recommendation for sodium intake (2000 mg/d) and 16 (2.3%) met the goal for potassium intake (≥3510 mg/d). Urinary sodium (β coefficient 1.3, 95% CI: 0.7, 1.8, p0.001) and potassium (β coefficient 2.1, 95% CI: 1.0, 3.2, p0.001) were found to be associated with systolic blood pressure in the univariate analysis but not in the multivariate analysis.Sodium intake was higher and potassium intake was lower than the WHO recommendations in this healthy Mexican population. Sodium and potassium intakes were not associated with blood pressure at the mean levels of intake observed in this population, after adjusting for key variables.

The assessment of spontaneous variability of blood pressure and heart rate is based on specific physiological hypotheses about dynamic features, for example, the baroreflex modulation of heart rate over time in daily life. Usually, arterial baroreflex control of heart rate is explored without delays between blood pressure and heart rate data points, within a narrow range of values, excluding the analysis of saturation regions or low-threshold changes. In this work, we examine the dynamic interactions between systolic blood pressure (SBP) and interbeat interval (IBI), in 15-min length time series and for the first time using the analysis of diagonals derived from a cross-recurrence plots in healthy persons and end-stage renal disease (ESRD) patients. We found that ESRD patients have stronger intermittent dynamical interactions between IBI and SBP, but they lose most of the dynamical interactions. Although healthy subjects exhibit a continuously changing order of precedence between IBI and SBP at different lags, ESRD patients preserve this changing order of precedence only for lags >0 beats. NEW & NOTEWORTHY This study is the first to compare the time-variant pattern of systolic blood pressure (SBP) and interbeat interval (IBI) coupling between ESRD patients and healthy volunteers through the analysis of diagonal in cross-recurrence plots, and in the face of an orthostatic challenge. Our results demonstrated alternant interactions on the order of precedence (IBI → SBP or SBP→ IBI) at different time delays. This pattern is different in resting position and during active standing for the two groups studied, and interestingly, some association patterns are lost in ESRD patients. These patterns of alternant interactions on the order of precedence could be related to autonomic neural activities and cardiovascular synchronization at different scales both in time and space. This could reflect physiological adaptive flexibility of cardiovascular regulation. Losing some association patterns in ESRD may be the result of chronic adjustments of many physiological mechanisms (including chronic sympathetic hyperactivity), which could increase cardiovascular vulnerability to hemodynamic challenges.

Heart rate variability (HRV) has been used to indirectly assess and study the autonomic nervous system (ANS). For the analysis of HRV, two different time windows are recommended.

Blood pressure is a very important physiological parameter given it provides information about the state of the cardiovascular system. The present work describes the development of an electromechanical device to measure the systolic and diastolic blood pressure in the digital artery. The measurements are based on the onset of the photoplethysmographic pulse signal when the artery is decompressed during the deflation of a neonatal cuff placed on the middle finger. The device consists of an optical sensor, a pressure transducer, an electronic system based on an Arduino development board and a graphical computer interface written in Matlab. To validate our device we used a Portapres® system. Simultaneous pressure measurements made with our device and the Portapres® were continuously recorded from 9 subjects in sitting and standing positions. The systolic (SBPDA) and diastolic (DBPDA) blood pressures measured from the digital artery were analytically compared. Results obtained for the SBPDA yielded R2 values of 0.59 and 0.76, as well as 0.59 and 0.85 for the DBPDA for the sitting and standing positions evaluated. A comparison of SBPDA values using the Bland-Altman plot yielded mean values of µ = 3.88 ± 11.97 mmHg and µ = −0.6 ± 9.59 mmHg for the sitting and standing position, respectively.

Introduction: Patients in hemodiafiltration (HDF) eliminate volume overload by ultrafiltration. Vascular volume loss is among the main mechanisms contributing to adverse events such as intradialytic hypotension. Here, we hypothesize that the intradialytic exercise (IDEX) is an intervention that could improve the acute response of physiological mechanisms involved during vascular volume loss. To test this hypothesis, we evaluated the hemodynamic response to mild aerobic exercise during HDF. Methods: Nineteen end-stage renal disease (ESRD) patients (11 women: 40 ± 10.8 years old, and 8 men: 42 ± 21 years old) receiving HDF thrice a week, with 6 months of previous physical conditioning, participated in this study. Three HDF sessions were scheduled for each patient: 1 resting in supine position, 1 resting in sitting position, and 1 doing aerobic exercise. The first 2 sessions were taken as control. The ultrafiltration rate was set to 800 mL/h in each session. The hemodynamic response was monitored through the relative blood volume (RBV), and cardiovascular variables measured noninvasively by photoplethysmography. Adequacy variables such as Kt/V and percentage reduction of urate, urea, creatinine (Cr), and phosphate were also monitored. Findings: The decrease rate of the RBV was smaller in the session with IDEX compared to the sessions with no exercise. No differences were found neither in the cardiovascular variables nor in the adequacy variables among the 3 sessions. There were no hypotension events during the session with exercise, and 8 events during the sessions without exercise (p = 0.002). Discussion: Mild exercise during HDF decreased the RBV drop and was associated with less hypotension events. The lack of differences in the hemodynamic variables suggests an adequate acute response of cardiovascular compensation variables to intradialytic hypovolemia.

Aortic-valve sclerosis increases cardiovascular mortality risk and precedes aortic-valve stenosis, but its mechanisms are not well understood. The purpose of this study was to compare the cardiac autonomic modulation and inflammation markers between subjects with aortic-valve normal leaflets and subjects with aortic-valve sclerosis. According to 2-D transthoracic echocardiograms, 61 middle-aged volunteers without chronic or acute illnesses were classified in two groups: with no aortic-valve sclerosis (NAVS, N = 16) and with aortic-valve sclerosis (AVS, N = 45). An electrocardiogram at the supine position and active standing was collected to estimate heart rate variability (HRV) indices. A blood sample was obtained to quantify markers of inflammation. Compared to NAVS, AVS subjects showed higher levels of IL-6 (1619 &plusmn, 650 vs. 1169 &plusmn, 676 pg/mL, p = 0.044) as well as TNF&alpha, (370.8 &plusmn, 182.0 vs. 247.3 &plusmn, 188.2 pg/mL, p = 0.032), and larger low-frequency (LF) to high-frequency (HF) ratio during supine position (Ln(LF/HF) = 0.85 &plusmn, 0.85 vs. 0.11 &plusmn, 0.69, p = 0.003). Multiple logistic regression analysis showed that AVS was independently associated with LF/HF, TNF&alpha, and left ventricle mass index (p &lt, 0.05). In conclusion, a significant reduction of the parasympathetic-driven cardiac modulation and low-grade inflammation occurs in aortic-valve sclerosis.

Background and aimsMany countries lack resources to identify patients at risk of developing Type 2 diabetes mellitus (diabetes). We aimed to develop and validate a diabetes risk score based on easily accessible clinical data.MethodsProspective study including 5277 participants (55.0% women, 51.8±10.5 years) free of diabetes at baseline. Comparison with two other published diabetes risk scores (Balkau and Kahn clinical, respectively 5 and 8 variables) and validation on three cohorts (Europe, Iran and Mexico) was performed.ResultsAfter a mean follow-up of 10.9 years, 405 participants (7.7%) developed diabetes. Our score was based on age, gender, waist circumference, diabetes family history, hypertension and physical activity. The area under the curve (AUC) was 0.772 for our score, vs. 0.748 (pConclusionOur clinically-based score shows encouraging results compared to other scores and can be used in populations with differing diabetes prevalence.

Power spectral analysis of heart rate variability (HRV) offers a possibility to non-invasively quantify autonomic cardiac regulation. The technique splits the spectrum of the HRV into high frequency (HF), low frequency (LF) and very-low frequency (VLF) bands, and relates their power content to parasympathetic outflow, sympathetic outflow, and hormonal factors as well as thermoregulation, respectively. In this work, we applied this technique on HRV data from 20 end-stage renal disease (ESRD) patients to estimate power distribution in these three bands as well as their changes respect to time during hemodiafiltration (HDF) therapy; as an indirect way to assess the modulatory activity over the cardiac system. HRV data was processed using the continuous wavelet transform (CWT), power was estimated using 5-min as well as 10-min epochs for comparison purposes, and the results were normalized to unity before linear regression analysis. For 5-min epochs, the LF power increased (p = 0.035), while there were no significant changes in the HF power (p = 0.2). In contrast, for 10-min epochs, both the LF (p = 0.002) and HF (p = 0.043) power decreased, while the VLF power increased (p

Excessive dietary sodium is associated with elevated blood pressure (EBP). Bread products are identified as one of the main sources of daily sodium intake. The objective of this cross-sectional study was to evaluate the association between bread and others cereal products consumption with EBP. Frequency intake of a standard serving of bread and other cereal products was recorded and categorized as: &le, 3 times/month or never (reference category group) and &ge, once/week. EBP was defined as systolic blood pressure (SBP) &ge, 120 mmHg and/or diastolic blood pressure (DBP) &ge, 80 mmHg. Raw and adjusted odds ratios (OR) for the association between consumption of the studied food products and blood pressure status were estimated. Overall, 2011 participants aged 37.3 &plusmn, 9.1 years old were included. In the models adjusted for relevant covariates, consumption of one piece of bolillo or telera (OR = 1.39, 95% CI = 1.01&ndash, 1.89) &ge, once/week was associated with an increased risk of EBP, compared to the reference category. Also, participants consuming one bowl of high-fiber breakfast cereal once/week were less likely to have EBP (OR = 0.73, 95% CI = 0.53&ndash, 0.98). Initiatives to reduce sodium levels in bread products such as bolillo and telera are needed in Mexico to help manage the cardiovascular risk at the population level.

The inter beat interval (IBI) duration and systolic blood pressure (SBP) are cardiovascular variables related through several feedback mechanisms. We propose the analysis of diagonal lines in cross recurrence plots (CRPs) from IBI and SBP embedded within the same phase space to identify events where trajectories of both variables concur. The aim of the study was to describe the relationship between IBI and SBP of healthy subjects using CRP and diagonal analysis during baseline condition—supine position (SP)—and how the relationship changes during the physiological stress of active standing (AS). IBI and SBP time series were obtained from continuous blood pressure recordings during SP and AS (15 min each) in 19 young healthy subjects. IBI and SBP time series were embedded within a five-dimensional phase space using an embedding delay estimated from cross correlation between IBI and SBP. During SP, mean CRP showed high determinism (≥85%) and also brief but repeated events where both variables stay within a reduced space. Most quantitative recurrences analysis indexes of CRP increased significantly (p

Objective: To characterize the multifractal behavior of the beat to beat heart-period or RR fluctuations in fibromyalgia patients (FM) in comparison with healthy-matched subjects. Methods: Multifractral detrended fluctuation analysis (MDFA) was used to study multifractality in heartbeat times-series from 30 female healthy subjects and 30 female patients with fibromyalgia during day and night periods.The multifractal changes as derived from the magnitude and sign analysis of these RR fluctuations were also assessed. Results: The RR fluctuations dynamics of healthy subjects showed a broad multifractal spectrum. By contrast, a noticeable decrease in multifractality and non-linearity was observed for patients with fibromyalgia. In addition, the spectra corresponding to FM subjects were located on the average to the right of the spectra of healthy individuals, indicating that the local scaling exponents reflect a smoother behavior compared to healthy dynamics. Moreover, the multifractal analysis as applied to the magnitude and sign heartbeat series confirmed that, in addition to a decreased nonlinearity, fibromyalgia patients presented stronger anticorrelation in directionality, which did not remain invariant for small or rather larger fluctuations as it occurred in healthy subjects. Conclusion: When compared to healthy controls, fibromyalgia patients display decreased nonlinearity and stronger anticorrelations in heart period fluctuations. These findings reinforce the hypothesis of the potential role of the dysfunctional autonomic nervous system in the pathogenesis of fibromyalgia.

The spectral analysis of heart rate variability (HRV) is an accepted method for assessing the autonomic control of the cardiovascular system. The electrocardiographic recordings used to extract the time interval between consecutive R waves (RR intervals or tachogram) should last 5 min or 24 h, according to the guidelines published in 1996 by the European Heart Journal (TASK FORCE). The three frequency bands recognized are the VLF (0.003–0.04 Hz), the LF (0.04–0.15 Hz) and the HF (0.15–0.4 Hz), which are associated with cardiovascular modulatory mechanisms. Given that the estimation of VLF in 5 min recordings is unreliable and that in some circumstances (orthostatism, controlled breathing, etc.) it is not possible to obtain 24 h recordings, it becomes necessary to consider other window sizes in order to estimate it with greater certainty. To show how the size of the window affects the estimation of the power spectral density, synthetic signals were evaluated using the Welch periodogram, comparing the power and spectral resolution obtained with conventional 5 min windows versus results obtained with windows that ranged from 300 to 3000 s in steps of 300 s, plus an additional one of 4000 s. Noise-free signals were generated, contaminated with White Gaussian Noise and mounted on a linear trend, to approximate the conditions of a real tachogram. The results suggest that the optimal size of the analysis window is 50 min, decreasing the power estimation error of the VLF band from 24.91 to 8.06%, increasing the spectral resolution and increasing the confidence in the evaluation of the three frequency bands defined for the HRV, especially for the VLF. These results suggest an alternative analysis for recordings with duration less than 24 h but that require evaluating the VLF, as in the HRV recordings of patients during their haemodialysis session.

Hemodialysis (HD) is usually performed with the gradually decreasing ultrafiltration rate (UFR) profile (dUFR). The aim of the present study was to compare the hemodynamic response to HD with the dUFR to that of HD with the gradually increasing UFR profile (iUFR). The study population included 10 patients (three women, mean age: 28 ± 8 years) undergoing maintenance HD who had reached dry weight without taking antihypertensive medications. Each patient received (in random order) one HD session with the dUFR and another with the iUFR (both with 3 h total UFR = 2200 mL). Hemodynamic response was evaluated with a brachial blood pressure (BP) monitor, echocardiogram and Portapres to measure digital BP, heart rate, cardiac output, stroke volume, and peripheral resistance. Mean values were compared at each HD hour during the first 3 h of a 4-h HD session. The HD characteristics, including Kt/V, were similar for both UFR profiles. Relative blood volume decreased more gradually and linearly with the iUFR. Hemodynamic variables were not significantly different between the two profiles, but brachial BP was more stable with the iUFR. Digital diastolic BP increased with both profiles. Peripheral resistance increased with both profiles, and tended to increase more with the iUFR. Echocardiographic variables changed similarly during the HD session with both profiles. In conclusion, these two UFR profiles are similar in most hemodynamic variables. The statistical equivalence of both profiles suggests that either could be prescribed based on the clinical characteristics of the patient.

Purpose Little is known about the autonomic response to active standing in vasovagal syncope, and most works have focused on children or adolescents. The aim of this work was to study the changes in cardiac autonomic modulation in adult patients with vasovagal syncope through heart rate variability analysis with linear and short-term complexity (alpha-1) indexes during supine position and active standing, in patients with positive or negative head-up tilt test (HUTT). Methods Twenty-five patients with vasovagal syncope were included. Heart rate variability linear and short-term complexity (alpha-1) indexes were recorded during an active standing test (15 minutes in each position) and compared among patients grouped by HUTT outcome and between positions. Results During supine position, positive HUTT (+HUTT) patients had longer mean RR (1016 [850-1051] milliseconds), higher pNN50 (17.7 [9.2-26.2]), lower sympathovagal balance (1.3 [0.5-1.7]), and alpha-1 (0.9 [0.8-1.0]) than negative HUTT (-HUTT) patients (871 [776-969] milliseconds, 8.8 [2.1-14.5], 2.9 [1.3-3.9], and 1.2 [1.0-1.1], respectively). During active standing, heart rate and alpha-1 increased in both groups; in +HUTT patients, pNN50 decreased, whereas sympathovagal balance increased. The magnitude of change between positions of sympathovagal balance and alpha-1 was 6.1 and 4.8 times larger in +HUTT than -HUTT patients, respectively. Conclusions The underlying cardiac autonomic mechanism in vasovagal syncope may involve different autonomic patterns in subjects with a history of recurrent syncope and +HUTT or -HUTT.

Heart rate variability (HRV) is an analysis tool through which is possible to analyze the autonomic nervous system (ANS) in its two sympathetic and parasympathetic pathways. Photoplethysmography (PPG) has been used to determine beat-to-beat blood volume changes in both arterial and surrounding tissues. In this work we used a characteristic of the pulsatile signal, mainly associated with the changes in the arterial diameters, the amplitude of the photoplethysmographic beat to beat pulse (PPGAV) and its corresponding association with the modification of the ANS activity. In this study participated a group of thirty volunteers (15M, 15F, 22.9±1.95 years). In order to stimulate the ANS we used the five minutes clinostatism to orthostatism maneuver by which we obtained the tachograms and the amplitudes of the PPG pulses. Later the frequency domain analysis was carried out by Statistica Software, determining the high and low frequency components for both maneuvers. To establish the linear relationship in the frequency domain, the spectral coherence function was used. The analysis of HRV and PPGAV in this group of volunteers revealed that there is a decrease in the PPG amplitude at the clinostatism / orthostatism postural change, suggesting an increase of the sympathetic activity towards the blood vessels, which causes vasoconstriction, thus reflecting a decrease in the value of the spectral coherence in response to the stimulus caused by the maneuver.

The scaling properties of heart rate variability data are reliable dynamical features to predict mortality and for the assessment of cardiovascular risk. The aim of this manuscript was to determine if the scaling properties, as provided by the sign and magnitude analysis, can be used to differentiate between pathological changes and those adaptations basically introduced by modifications of the mean heart rate in distinct manoeuvres (active standing or hemodialysis treatment, HD), as well as clinical conditions (end stage renal disease, ESRD). We found that in response to active standing, the short-term scaling index (α1) increased in healthy subjects and in ESRD patients only after HD. The sign short-term scaling exponent (α1sign) increased in healthy subjects and ESRD patients, showing a less anticorrelated behavior in active standing. Both α1 and α1sign did show covariance with the mean heart rate in healthy subjects, while in ESRD patients, this covariance was observed only after HD. A reliable estimation of the magnitude short-term scaling exponent (α1magn) required the analysis of time series with a large number of samples (>3000 data points). This exponent was similar for both groups and conditions and did not show covariance with the mean heart rate. A surrogate analysis confirmed the presence of multifractal properties (α1magn > 0.5) in the time series of healthy subjects and ESDR patients. In conclusion, α1 and α1sign provided insights into the physiological adaptations during active standing, which revealed a transitory impairment before HD in ESRD patients. The presence of multifractal properties indicated that a reduced short-term variability does not necessarily imply a declined regulatory complexity in these patients.

Introduction Systemic hypertension (HTN) is a common risk factor for cardiovascular disease. In Mexico, HTN prevalence has increased over time and is currently 31%. Nonetheless, information about the country9s HTN incidence and its associated risk factors is scarce. Understanding this condition is a priority for identifying the scope of primary prevention. The main objective of this study is to evaluate the effect of traditional and non-traditional risk factors on the incidence of HTN in a cohort of healthy Mexico City residents under biannual follow-up for 10 years. Methods and analysis A prospective longitudinal study is proposed in which clinically healthy residents of Mexico City between 20 and 50 years old will be recruited; the participants will be evaluated every 2 years over a period of 10 years or until they develop HTN. Evaluations regarding sociodemographic, clinical, anthropometric, biochemical, diet, physical activity, stress, sleep quality, alcohol and tobacco consumption factors will be performed. The participants will be recruited from the 16 municipalities of Mexico City through promotional strategies aimed at the community and will be clinically evaluated at a tertiary care institution, Instituto Nacional de Cardiologia Ignacio Chavez (National Institute of Cardiology Ignacio Chavez), located in Mexico City, Mexico. Sample size estimated for this study is 3436, and the Cox proportional hazards model will be used to estimate HRs for the association between explanatory variables and HTN using both raw and adjusted data. Ethics and dissemination This study was approved by the Institutional Bioethics Committee of the Instituto Nacional de Cardiologia Ignacio Chavez (National Institute of Cardiology Ignacio Chavez) under number 13-802. Findings from this study will be disseminated through scientific papers and research conferences.

The aim of this work was to measure the impact of active orthostatism and hemodialysis (HD) upon heart rate variability (HRV) in chronic renal failure (CRF) patients before and after HD. Nineteen healthy subjects (age 27 ± 8 years old, 13 were female) and 19 unmedicated CRF patients with HD thrice per week (average HD vintage = 12 months, age 32 ± 9 years old, 11 were female) were included. Five-minute length HRV time series were obtained during supine position and orthostatism. Recordings from CRF patients were obtained before and after HD. Time domain and frequency domain HRV indexes were compared by analysis of variance. The correlation between each HRV index and change in sympathetic weighting induced by different maneuvers was tested by Kendall’s Tau correlation. A p value

A 40-year-old woman was found to have bilateral Adie’s pupils and generalized muscle stretch areflexia. She did not have orthostatic hypotension but, in an ECG strip in the office, she appeared to have an almost fixed heart rate. We thus studied the heart rate variability (HRV) and the systolic blood pressure variability (SBPV) in supine and standing position and also during rhythmic breathing. We found a decreased HRV in the time domain with very low standard deviation in supine and standing position and during rhythmic breathing. HRV in the frequency domain was low with a decrease in the absolute power of HF and LF and a decrease in the sympathovagal balance in supine and standing positions. SBPV in the time and frequency domains was found to be normal. This patient with Holmes-Adie syndrome had an asymptomatic severe loss of HRV and a preserved SBPV. The global decrease in the HRV in the time and frequency domains indicated that she had both vagal and sympathetic cardiac denervation, whereas the preserved SBPV suggested normal innervation of the blood vessels.

Heart Failure and Respiratory Clinic 1 and COPD Investigation Department 2 at Instituto Nacional de Enfermedades Respiratorias “Ismael Cosio Villegas”. Instrumentation Department 3 at Instituto Nacional de Cardiologia “Ignacio Chavez” Mexico City, Mexico. Backgroun: The deterioration of endothelial function represents a potential pathophysiological link between COPD and cardiovascular disease, especially with Heart Failure (HF). Objective: To evaluate endothelial function (EF) through Photoplethysmography in patients with COPD and HF. Methods: Cross-sectional study in 160 patients diagnosed with COPD. The EF was assessed through photopletismogry. From the pulse wave was analyzed: the shape and maximum amplitude time / total time index of the same, (TAM / TT) before and after ischemia-induced by arterial obstruction. Endothelial dysfunction (ED) was considered whether the post-ischemic wave did not increase at least 10% of the value or with the TAM/TT ≥ 30. Results: A population of 160 patients were included; with HF and COPD (n = 17) and COPD (n = 143), the age of patients with heart failure and COPD was 56.47 ± 13.81 and 70.73 ± 10.90 COPD, p = 0.06. In photopletismographic findings found higher TAM / TT index in patients with COPD and HF 40 ± 0.05 compared with patients who had COPD alone, 34 ± 0.073, ( p= 0.027). No group differences were found in comorbilities. Conclusions: The ED was worst in patients with COPD and HF compared to those who only have in diagnosis of COPD. Keywords: Right heart failure, chronic obstructive pulmonary disease, endothelial dysfunction, photoplethysmography.

Introduction: Respiratory function is greatly related to lipid metabolism and production of vasoactive substances and prostaglandins that can be synthesized from certain fatty acids which along with catecholamines are substrates able to injure the endothelium vessels when there´s an excessive production or are not consumed. Objective: To describe the relationship between dietary lipids and endothelial dysfunction (ED) in patients with respiratory failure (RF). Methods: Cross-sectional study in patients with RF (n = 27) from the Heart and Respiratory Failure Clinic at Instituto Nacional de Enfermedades Respiratorias “Ismael Cosio Villegas”. Endothelial function was evaluated through Photoplethysmography, ED was diagnosed from the pulse wave with a maximum amplitud time/total time (MAT / TT) index greater than 30. Results: The mean age of the population was 70 years, and no significant differences in comorbidities were found between the groups with and without ED. Patients with DE had a significant lower linoleic acid intake compared to subjects without ED (8.12 [6.20-10.63] vs 8.77 [4.05-11.75], p = 0.003), the same pattern was observed with Omega 3 fatty acids (1.03 [0.55- 1.43] vs 1.64 [1.20-2.23], p = 0.092) and linolenic acid (0.98 [0.49-1.42] vs 1.62 [1.17-2.23], p = 0.070), although this last results only had a significant tendency. Conclusion: Linoleic acid is a polyunsaturated fatty acid from the omega 6 series and its consumption could benefit the endothelial function in RF patients.

The aim of this work was to evaluate the short-term fractal index (α

To improve the identification of peaks and feet in photoplethysmographic (PPG) pulses deformed by myokinetic noise, through the implementation of a modified fingertip and applying adaptive filtering.PPG signals were recordedfrom 10 healthy volunteers using two photoplethysmography systems placed on the index finger of each hand. Recordings lasted three minutes andwere done as follows: during the first minute, both handswere at rest, and for the lasting two minutes only the left hand was allowed to make quasi-periodicmovementsin order to add myokinetic noise. Two methodologies were employed to process the signals off-line. One consisted on using an adaptive filter based onthe Least Mean Square (LMS) algorithm, and the other includeda preprocessing stage in addition to the same LMS filter. Both filtering methods were compared and the one with the lowest error was chosen to assess the improvement in the identification of peaks and feet from PPG pulses.Average percentage errorsobtained wereof 22.94% with the first filtering methodology, and 3.72% withthe second one. On identifying peaks and feet from PPG pulsesbefore filtering, error percentages obtained were of 24.26% and 48.39%, respectively, and once filtered error percentageslowered to 2.02% for peaks and 3.77% for feet.The attenuation of myokinetic noise in PPG pulses through LMS filtering, plusa preprocessing stage, allows increasingthe effectiveness onthe identification of peaks and feet from PPG pulses, which are of great importance for medical assessment.

To evaluate a modified sequence method with delayed time series for baroreflex sensitivity (BRS) estimation during supine position and orthostatism in healthy human beings.Nineteen clinically healthy volunteers (12 men, age 28.4 ± 6.2 years old) were included. Blood pressure recordings were obtained during supine position and orthostatism (15 min each) with a Finometer. Systolic blood pressure (SBP) and inter beat intervals (IBI) measured from all heartbeats were used to estimate BRS in both positive and negative sequences, with SBP delayed between 0 and 5 heartbeats. BRS estimations were compared by ANOVA, p 0.05 was considered significant. Optimal recording time based on fixed BRS error estimation was calculated for each time series.BRS estimation was similar between positive and negative sequences in all conditions (BRS = 12.0 ± 2.0 ms/mmHg in supine position, delay 0). BRS with no delay was similar to BRS with delays between 1 and 5 heartbeats. Compared to supine position, BRS was smaller in orthostatism in all delays (BRS = 8.0 ± 2.0 ms/mmHg with delay 0). The shortest optimal recording time with delayed time series was similar in supine position and orthostatism (4.3 ± 1.7 vs. 3.74 ± 0.07 min, respectively). Estimation error was linearly correlated to IBI, regardless of the delay.BRS estimation with sequence method improves with delayed time series, during supine position and orthostatism. Reduced BRS estimation error and recording time from this method could benefit studies with large populations or patients with low tolerance to orthostatism.

Objetivo: Desarrollar un equipo de monitoreo de señales de electrocardiografía (ECG) y frecuencia cardiaca (FC) portátil, comunicado con un teléfono móvil mediante el protocolo de comunicación Bluetooth (BT), para su visualización en pantalla. Métodos: Se diseñó un sistema de monitoreo que en su sección electrónica realiza la adquisición de la señal de ECG, así como su amplificación, filtrado, conversión analógica a digital y transmisión por BT del ECG y la FC. Se desarrollaron dos programas para el sistema. El primero calcula la FC a través de la identificación del QRS, y envía las señales del ECG y FC al teléfono móvil. El segundo es una aplicación que permite adquirirlas y visualizarlas en la pantalla del móvil. Resultados: Se desarrolló un sistema electrónico portátil alimentado por una batería de 9 volts, de amplificación y ancho de banda que cumplen con los estándares internacionales, para monitoreo de ECG. La identificación del complejo QRS se realizó con el algoritmo de la segunda derivada, mientras que los programas realizados permiten enviar y recibir la información del ECG y la FC a través de BT, para visualizarlos en la pantalla del móvil. El monitoreo es factible hasta 15 m de distancia. Se probó en distintos móviles de Nokia®, Sony Ericsson® y Samsung®. Conclusiones: Este sistema muestra una alternativa de monitoreo móvil, con un teléfono por medio de BT y la programación en Java 2 Micro Edition (J2ME). Permite registrar el trazo del ECG y la FC, y puede implementarse en diferentes móviles.

This study evaluated the usefulness of the three-dimensional representation of electrocardiogram traces (3DECG) to reveal acute and gradual changes during a full session of hemodiafiltration (HDF) in end-stage renal disease (ESRD) patients. Fifteen ESRD patients were included (six men, nine women, age 46 ± 19 years old). Serum electrolytes, blood pressure, heart rate, and blood urea nitrogen (BUN) were measured before and after HDF. Continuous electrocardiograms (ECGs) obtained by Holter monitoring during HDF were used to produce the 3DECG. Several major disturbances were identified by 3DECG images: increase in QRS amplitude (47%), decrease in T-wave amplitude (33%), increase in heart rate (33%), and occurrence of arrhythmia (53%). Different arrhythmia types were often concurrent and included isolated supraventricular premature beats (N = 5), atrial fibrillation or atrial bigeminy (N = 2), and isolated premature ventricular beats (N = 6). Patients with decrease in T-wave amplitude had higher potassium and BUN (both before HDF and total removal) than those without decrease in T-wave amplitude (P

The kidneys are organs that can be severely impaired by metabolic syndrome (MS). This is characterized by the association of various pathologies such as hypertension, dyslipidemia, and type-2 diabetes. Glycine, a nonessential amino acid, is known to possess various protective effects in the kidney, such as a decrease in the deterioration of renal function and a reduction of the damage caused by hypoxia. In a rat model of MS, the effect of glycine on the cyclooxygenase (COX) pathway of arachidonic acid (AA) metabolism was studied in isolated perfused kidney. MS was induced in Wistar rats by feeding them a 30% sucrose solution for 16 weeks. The addition of 1% glycine to their drinking water containing 30% sucrose, for 8 weeks, reduced high blood pressure, triglyceride levels, insulin concentration, homeostatis model assessment (HOMA) index, albuminuria, AA concentration in kidney homogenate, renal perfusion pressure, prostaglandin levels, PLA2expression, and COX isoform expression, compared with MS rats that did not receive the glycine supplement. Glycine receptor expression decreased significantly with MS, but glycine treatment increased it. The results suggest that in the MS model, 1% glycine treatment protects the kidney from damage provoked by the high sucrose consumption, by acting as an anti-inflammatory on the COX pathway of AA metabolism in kidney.