Fibromyalgia beyond reductionism. Heart rhythm fractal analysis to assess autonomic nervous system resilience.

OBJECTIVES: The prevailing linear reductionist medical model seems unable to explain complex multisymptomatic illnesses such as fibromyalgia (FM) and similar maladies. Paradigms derived from the complexity theory may provide a coherent framework for these elusive illnesses. Along these lines is the proposal that FM represents a degradation of our main complex adaptive system (the autonomic nervous system, ANS), in a failed effort to adjust to a hostile environment. Healthy complex systems have fractal structures. Heart rate fractal-like variability reflects resilient ANS performance. Our aim was to measure the heart rate variability (HRV) fractal scaling index in FM patients and to correlate this index with clinical symptoms. METHOD: We studied 30 women with FM and 30 controls. All participants filled out questionnaires assessing the severity of FM. The HRV fractal scaling index was estimated during 24 h using detrended fluctuation analysis (DFA). RESULTS: The fractal scaling index alpha-1 was higher in FM patients than in controls (mean ± sd: 1.22 ± 0.10 vs. 1.16 ± 0.09; p = 0.031). There was a positive correlation between the fractal scaling index alpha-1 and the visual analogue scale (VAS) for depression (Spearman's ρ = 0.36, p = 0.04). CONCLUSIONS: The heart rate fractal exponent alpha-1 is altered in FM patients, suggesting a rigid ANS performance. This tangible non-linear finding supports the notion that FM may represent a degradation of our main complex adaptive system, namely the ANS.

Risk of introduction of H5N1 HPAI from Europe to Spain by wild water birds in autumn.

Highly pathogenic avian influenza (HPAI) subtype H5N1 continues to circulate across Eurasia and Africa since its unprecedented rapid spread in 2005. Diffusion by wild bird movements has been evidenced in the European Union in 2006 and 2007. Spain is an important wintering quarter for aquatic birds from northern latitudes, so identifying the critical areas and species where an outbreak is prone to happen is necessary. This work presents an assessment of the risk of introduction of H5N1 HPAI in Spain by aquatic wild birds estimating a relative risk value per province. For this purpose, an assessment of the release and exposure to the risk of infection with H5N1 HPAI of 25 selected water bird species has been carried out. Parameters considered in the assessment include H5N1 HPAI notifications from 2006 to 2008 and factors that favour the occurrence or persistence of H5N1 HPAI (wetlands' surface, low temperatures), together with aquatic wild birds' movements parameters (departure, destination, stop-overs, abundance) and parameters relative to the susceptible population in Spain: poultry density and wild aquatic abundance. Results show the relative risk for each Spanish province of experiencing H5N1 HPAI introduced by wild aquatic birds helping to identify higher risk areas.

Metabolic variability analysis using a mixing chamber-breath by breath based indirect calorimeter and the clino-ortho maneuver.

This work proposes the clino-ortho maneuver to analyze the metabolic energy expenditure variability by Indirect Calorimetry (IC). This analysis uses a hybrid calorimeter which includes simultaneously the mixing-chamber (MC) and the breath by breath (BbB) IC techniques. VO2 and VCO2 short-term variability was characterized as metabolic variability in the MC technique by intra-group standard deviation averages. When the BbB technique was used the metabolic variability characterization was done by VO2 and VCO2 discrete time series power spectrum analysis in the 0-0.5 Hz band. Thus a statistical population of 17 young healthy volunteers was studied using a clino-ortho maneuver with 30-30 minutes in each position after 8 hours of fasting. The results showed an energy expenditure change of 40% in Kcal/day (p<0.01). The metabolic variability was partially significant using the MC technique while BbB total power spectrum changed from 35 to 60 for the VO2 and from 24 to 37 for the VCO2 (ml/bth)(2), (p<0.05) in the region from 0 to 0.04 Hz. It was concluded that using this new measurement technique and the clino-ortho maneuver metabolic variability information not yet studied was revealed.

A simple model implementation to measure breath by breath the VO2 and VCO2 by the indirect calorimetry technique.

This paper proposes a discrete random time series modeling for the VO2 and VCO2 measurement in the indirect calorimetry technique (ICT). Mathematical equations are developed in order to establish clear differences between the breath-by-breath and mixing chamber measurement based calorimeters. This simple model offers not only a physiological ICT definition approach but also defines the idea of VO2 and VCO2 short-term variability information for research. The preliminary results show a new physiological information when a computer oriented algorithm model implementation was applied to a data acquisition system in order to obtain the power spectrum analysis from a typical observation subject submitted to the clino-ortho maneuver.

Steady State Condition in the Measurement of VO2and VCO2by Indirect Calorimetry.

Resting Metabolic Rate (RMR) is computed using VO2and VCO2short time 15-minute window measurement with Indirect Calorimetry (IC) instruments designed with mixing chamber. Steady state condition using a 10% variation coefficient criteria is the main objective to achieve metabolic long time prediction reliability. This study address how susceptible is the steady state VO2, VCO2measurement condition to the clino-orthostatic physiological maneuver. 30 young healthy subjects were analyzed. Only 18 passed the 10% variation coefficient inclusive criteria. They were exposed to 10 minutes clino-stage and 10 minutes orthostage. The hypothesis tests show not statistical significance (p< 0.1) in the average and variance analysis. It is concluded that the steady state is not influenced by the patient position IC test, probably because IC mixing chamber instruments are insensitive to detect a mayor physiological dynamics changes that can modify the steady state definition.

Hemodynamic performance in-vivo of a new ventricular assist device.

Nowadays, circulatory support has become a common practice in medicine and a standard in the treatments of Cardio Vascular Disease (CVD). A new Pneumatic Ventricular Assist Device (VAD) has been developed in México City. This paper shows the first results of acute in-vivo trials, intended to verify the new system for providing physiological flows and pressures. Two VADs were implanted to as right (RVAD), left (LVAD) support in a 65 kg pig. The support time was 20 minutes with RVAD, 20 minutes with LVAD and 20 minutes with Biventricular (BiVAD). The VAD proved its capability to maintain physiological parameters during the support time. We are satisfied with the results of this trial, and we believe this study will ascertain the first step on the next phase of invivo trials.

[A system for non-invasive measurement of arterial pulse velocity in different vascular territories]. / Sistema para la medición no invasiva de la velocidad del pulso arterial en diferentes territorios vasculares.

Blood pulse wave velocity (PWV) is a known index of arterial rigidity and its measurement has proved its usefulness in the study of some cardiovascular pathologies. In this study we describe the design and implementation of a system for noninvasive PWV determination in the aorto-braqui-humero-radial (A-->h), aorto-ileo-femoro-pedial (A-->f) and aorto-carotid (A-->c) regions. This system was examined with 36 normotensives (NT) and 34 hypertensives (HT) patients with (LVH, n = 20) and without (WLVH, n = 14) left ventricular hypertrofy. The equipment consist of a personal computer with an analog to digital converter and hardware and software items adapted to take simultaneously the electrocardiogram (ECG), two photopletismographic pulses and one oscilometric pulse. The Q-pP interval (time between a Q ECG wave and distal blood pulse) and the distance to the register sites are taken into account to calculate the beginning of cardiac prexpulsive period (time zero of pulse trip) which allow the determination of the PWV (in meters/second) from the aortic root to the distal point of the via. PWV was significant higher (p < 0.001) in HT vs. NT (A-->h: 9.3 +/- 2.6 vs. 7.2 +/- 0.8, A-->c: 9.5 +/- 2.8 vs. 6.0 +/- 1.9 and A-->f: 9.5 +/- 1.8 vs. 7.2 +/- 0.9) in each evaluated arterial region. Same thing occurred in cases with LVH vs. WLVH (A-->h: 10.5 +/- 1.6 vs. 8.0 +/- 1.9, A-->c: 10.2 +/- 1.9 vs. 8.0 +/- 1.9 and A-->f: 10.5 +/- 2.0 vs. 8.6 +/- 1.2) (p < 0.025). This is consistent with the relationship more pressure [symbol: see text] more rigidity and with other reports. This method may have clinical application.

[Provocation and measurement of retrograde pulsatile wave velocity in normal subjects and patients with systemic hypertension]. / Provocación y medición de la velocidad de la onda pulsátil retrógrada en sujetos normales e hipertensos sistémicos.

UNLABELLED: There are not published incruent methods of provocation and/or measurement of the velocity of the reflexive arterial pulse wave. This phenomenon is implicated in the pathogenesis of arterial hypertension. We describe that during compressive sphygmomanometry (CS) done in the forearm, reflexive waves are provoked that are register in the arm with an equipment developed by us, which measures the velocity of the antegrade (APWV) and the provoked retrograde (RPWV) pulse waves. The procedure consist in: 1) detection, capture and digitalization by pneumatic cuffs of oscillopulses of the arm and the forearm, 2) detection of finger photopulse to control the efficacy of CS, 3) measurement of APWV and RPWV by taking the conduction time travel distance of pulse wave between detectors arm-forearm and forearm-arm respectively. Thirty normal case (group A, GA) and 37 essential systemic hypertensive patients (group B, GB) were studied. Sixteen cases of GB had left ventricular hypertrophy (LVH). RESULTS: A reflexive wave was provoked in 99% of cases. The APWV (m/s) was 6.0 +/- 0.9 vs 7.5 +/- 1.3, p < 0.001 for GA and GB respectively. The RPWV (m/s) of the same groups were 1.8 +/- 0.3 vs 2.5 +/- 0.7, p < 0.001. The hypertensive cases with LVH had more RPWV than the cases without it (2.7 +/- 0.6 vs 2.3 +/- 0.6, p = 0.07). CONCLUSION: Hypertensive cases vs normals had higher antegrade and retrograde pulse wave velocities possible due to the major degree of arterial rigidity of the former. The method may be used in study of chronic arteriopathy.

Relationship between the site of a myocardial infarction and signal-averaged electrocardiogram indices.

We evaluated the relationship between the site of a myocardial infarction (MI) and signal-averaged electrocardiogram (SAECG) indices in both time-domain (TDA) and spectral turbulence (STA) analyses, and their implications in the prediction of infarct-related artery (IRA) patency, in 114 survivors of a first MI. They were divided into two groups based on MI location (57 anterior and 57 inferior). Patients with bundle branch block were not included. Fifty patients had been treated with thrombolytic therapy (TT). The STA was done in both XYZ-leads and in vector magnitude. Forty patients had an abnormal SAECG in TDA and 37 in STA, but only 22 (19%) in both (71% of agreement, kappa=0.35). Fifty-four patients (47%) had an occluded IRA. The best predictors from multivariate analysis of having an occluded IRA in the inferior MI group were: an abnormal Y-lead in STA (odds ratio 4.9; P=0.005); an abnormal RMS40 in TDA (odds ratio, 4.8; P=0.02); absence of TT (odds ratio, 9.15; P=0.001). Conversely, in the anterior MI group they were: an abnormal SAECG in TDA (odds ratio 6.83; P=0.005); absence of TT (odds ratio, 4.3; P=0.02). The multivariate receiver operator characteristic curves clearly showed the effect of MI location on the SAECG indices. This study suggests that the myocardial infarction site is an important factor for the variability and poor concordance between TDA and STA. Such differences may alter the predictive accuracy of SAECG. TDA and STA should be complementary methods, and the exploration in each orthogonal lead appears to be better than in vector magnitude.

[Dynamic and cinematic evaluation of the function of bioprosthesis in the aortic position: tester of cardiac valves]. / Evaluación dinámica y cinemática del funcionamiento de bioprótesis en posición aórtica: probador de válvulas cardiacas.

Twenty four pericardial valvular prostheses were tested in a valvular tester device. The valves considered were: 12 valves of the model that has being already in clinical use, manufactured in the Instituto Nacional de Cardiología "Ignacio Chávez", (INC II) and 12 valves of a model in an experimental stage, (PRT I.) The inner diameter in the two group considered were: 17, 19 and 21 mm. All the valves were tested in the aortic position in the valvular tester device. Behavior of the valvular prostheses were examined at various rates of pulsation, 60, 77, 105 and 159 per minute, with an ejection volume of 70 and 80 ml (range of flows between 4200 and 12720 ml min1). The pressure of the ventricular and aortic cameras were registered continuously, by external transducers, and in the other hand, the kinetic of the valves and the degree of opening were evaluated for direct view trough an special window. The grade of incompetence was too evaluated and expressed in percent of the stroke volume. The transvalvular pressure gradient was lower in INC II model valves, specially at moderate and high flows, and at same time had a largest functional area. The degree of incompetence was higher in the 19 and 21 mm diameter valvular subgroups than the same subgroups in the PRT I model. In relation to the 17 mm subgroup, significant differences were not find. The use of the valvular tester showed a basic utility in the hydrodynamic evaluation of the news bioprostheses design, and so in the quality control of the valves than has being manufacturing.

[High-fidelity spectrocardiography for the diagnosis of ischemic cardiopathy. The validation of a new method for analyzing the spectral components of the QRS complex]. / Espectrocardiografía de alta fidelidad para el diagnóstico de cardiopatía isquémica. Validación de un nuevo método para el análisis de los componentes espectrales del complejo QRS.

BACKGROUND: Analysis of high-frequency QRS complex envelope has been suggested as a method that could detect myocardial ischemia but the characteristics of the turbulence spectral from an spectral-temporal mapping into the QRS complex has not been studied yet. This is a prospective study of phase I for the validation of a new diagnostic test. AIMS: The aims for this study are: 1) To validate a new method for the detection of transient myocardial ischemia by both, high-frequency QRS and spectral turbulence analysis, which we have named "high-fidelity spectrocardiogram" (HFS). 2) To compare the sensitivity, specificity and accuracy of this HFS versus those obtained from nuclear medicine (NM-MIBI) and a conventional exercise ECG test, in a highly selected population. PATIENTS AND METHODS: Twenty-five patients (P) were studied: 10 P (Group B) with risk factors for coronary artery disease, without previous infarct, who had atypical precordial pain and a conventional ECG considered as "normal" by two cardiologists. The group A was formed by 15 P without risk factors or another kind of heart disease. All patients underwent a conventional surface ECG, which had to be normal in order to be considered for this study. Echocardiogram, exercise testing ECG and a NM-MIBI study were also normal. The HFS recording was taken before and after Dipyridamole testing, similar to the conventional method for the NM-MIBI (dipyridamole 0.25 mg/Kg/doses) studies. Our software for the analysis of QRS-frequencies was constructed from a language Turbo C++. The Fourier's transform allowed the construction of 3-dimensional graphics. After the determination of the best wide band for detecting changes in the frequency contained of QRS, the determination coefficients (r2) were obtained and compared before and after the challenge with dipyridamole. These changes were compared between groups (A vs B) later. RESULTS: The r2 changed more than 30% after dipyridamole in those patients in whom myocardial ischemia was demonstrated later by NM-MIBI. The sensitivity (85%) and specificity (90%) of HFS were similar to the nuclear medicine for identifying myocardial ischemia, but higher than a conventional exercise ECG testing (p.001). The main change in HFS was in the frequency-contained QRS in the 130-260 Hz band. The accuracy of our method was increased when an analysis of each orthogonal lead was made. There was a clear tendency of the group B to increase the QRS duration, while the contrary was found in group A, being the QRS the shorter (p.064). The chronological responses were different in those patients with ischemia. CONCLUSION: This study suggests that an episode of myocardial ischemia is able to change in a dramatic manner the frequency-contained within of the QRS complex, in spite of an unchanged ST segment in the conventional exercise ECG. We suggest that the HFS could be a good method for identifying myocardial ischemia. Its advantages could be important, particularly when the conventional exercise ECG is non informative.

[Food habits of the rainbow trout Oncorhynchus mykiss (Salmoniformes: Salmonidae) in an Andean creek of Venezuela]. / Hábitos alimenticios de la trucha arcoiris, Oncorhynchus mykiss (Salmoniformes: Salmonidae), en una quebrada altiandina venezolana.

Monthly stomach context samples of rainbow trout from Mucunután stream (Mérida, Venezuela), were collected from, March 1987 to February 1988 (n = 306). The major dietary components were Ephemeroptera, Trichoptera and Diptera. Baetodes sp. was the most important food item based on numerical composition (43%) and frequency of occurrence (88%). When the gravimetric method was used Leptonema sp. was the major dietary component. The diet was not a function of sex. The consumed fauna was more similar to the drift invertebrate fauna than to that of benthos (p < 0.01). The fluctuations on the stomach content paralleled changes of food availability in the environment.

[Risk of low birth weight in the Plaza de la Habana region]. / Riesgo de bajo peso al nacer en el área Plaza de la Habana.

The objective of this study was to confirm the risk factors (RF) for low birth-weight (LBW) and suggest new risk factors, which were analyzed separately and together, in order to define a program to be coordinated by family doctors to reduce the frequency of this problem. For this purpose, a retrospective cross-sectional survey was carried out with 57 cases (mothers who had had LBW babies) and 58 controls (mothers who had not had LBW babies). In addition, data were obtained from the prenatal records of mothers who received care at family doctors' offices and at the clinica in the Plaza de la Habana Area. Estimates were made of the relative risk and the percentage attributable risk of 107 hypothetical RF for LBW from a clinical-epidemiological and social standpoint. One-way analysis of variance, the chi-square test, multiple linear regression, and logistic regression were used to analyze the results, which suggested the following RF for LBW: family dysfunction, family crisis, lack of spousal support, extended family, failure to attend prenatal group sessions for pregnant women, and failure to receive education on how to prevent LBW. The multifactorial risk profile was the following: risk of [corrected] intrauterine growth retardation, family dysfunction, threat of preterm delivery, coffee-drinking, attendance at fewer than 11 prenatal checkups, and failure to attend prenatal group sessions for pregnant women. The variables excluded from the model were: low weight-for-height, lack of spousal support, smoking more than 10 cigarettes a day, and family history of LBW. The findings confirmed 10 of the suspected risk factors for LBW in Cuba and nine of those described in the international literature. Maternal age, spontaneous abortion, and alcohol consumption were not confirmed. Six RF for LBW preventable by the family doctor through his/her actions at the family and community level are identified, as is a multifactorial profile of six RF for LBW. On the basis of these results, proposals are made in regard to programming priorities and the implementation of strategies aimed at preventing LBW, and it is recommended that the study be continued with a larger sample.