Classification of ischemic and non-ischemic cardiac events in Holter recordings based on the continuous wavelet transform.

Holter recordings are widely used to detect cardiac events that occur transiently, such as ischemic events. Much effort has been made to detect early ischemia, thus preventing myocardial infarction. However, after detection, classification of ischemia has still not been fully solved. The main difficulty relies on the false positives produced because of non-ischemic events, such as changes in the heart rate, the intraventricular conduction or the cardiac electrical axis. In this work, the classification of ischemic and non-ischemic events from the long-term ST database has been improved, using novel spectral parameters based on the continuous wavelet transform (CWT) together with temporal parameters (such as ST level and slope, T wave width and peak, R wave peak, QRS complex width). This was achieved by using a nearest neighbour classifier of six neighbours. Results indicated a sensitivity and specificity of 84.1% and 92.9% between ischemic and non-ischemic events, respectively, resulting a 10% increase of the sensitivity found in the literature. Extracted features based on the CWT applied on the ECG in the frequency band 0.5-4 Hz provided a substantial improvement in classifying ischemic and non-ischemic events, when comparing with the same classifier using only temporal parameters. Graphical Abstract In this work it is improved the classification of ischemic and non-ischemic events. The main difficulty of ischemic detectors relies on the false positives produced because of non-ischemic events. After a preprocessing stage, temporal and spectral parameters are extracted from events of the Long Term ST Database. The novel parameters proposed in this work are extracted from the Continuous Wavelet Transform. A nearest Neighbor Classifier is used, obtaining a sensitivity and specificity of 84.1% and 92.9%, respectively.

La reforma tributaria de 2016 y los nuevos recursos para el sistema judicial en el marco del postconflicto en Colombia / The 2016 Tax Reform and the New Resources for the Judiciary in the Frame of Post Conflict in Colombia

Resumen La reforma tributaria del 2016 y la inclusión de rubros que contribuyan al logro de financiación de procesos que se deben atender para consolidar la paz, es una necesidad que bien administrada puede dar resultados favorables para llegar a la reconciliación, la paz, la democracia y la estabilidad política después del conflicto armado de más de 60 años en el país.

Abstract The 2016 tax reform and the inclusion of items, which contribute to the achievement of financial processes must be addressed in order to consolidate peace, is a need that, if well managed, can bear favorable results to reach reconciliation, peace, democracy, and political stability after the armed conflict, which has lasted more than 60 years in the country.

The impact of artifact correction methods of RR series on heart rate variability parameters.

Heart rate variability (HRV) analysis is widely used to investigate the autonomic regulation of the cardiovascular system. HRV is often analyzed using RR time series, which can be affected by different types of artifacts. Although there are several artifact correction methods, there is no study that compares their performances in actual experimental contexts. This work aimed to evaluate the impact of different artifact correction methods on several HRV parameters. Initially, 36 ECG recordings of control rats or rats with heart failure or hypertension were analyzed to characterize artifact occurrence rates and distributions, to be mimicked in simulations. After a rigorous analysis, only 16 recordings ( n = 16) with artifact-free segments of at least 10,000 beats were selected. RR interval losses were then simulated in the artifact-free (reference) time series according to real observations. Correction methods applied to simulated series were deletion, linear interpolation, cubic spline interpolation, modified moving average window, and nonlinear predictive interpolation. Linear (time- and frequency-domain) and nonlinear HRV parameters were calculated from corrupted-corrected time series, as well as for reference series to evaluate the accuracy of each correction method. Results show that NPI provides the overall best performance. However, several correction approaches, for example the simple deletion procedure, can provide good performance in some situations, depending on the HRV parameters under consideration. NEW & NOTEWORTHY This work analyzes the performance of some correction techniques commonly applied to the missing beats problem in RR time series. From artifact-free RR series, spurious values were inserted based on actual data of experimental settings. We intend our work to be a guide to show how artifacts should be corrected to preserve as much as possible the original heart rate variability properties.

Percepción de desórdenes musculoesqueléticos y aplicación del método RULA en diferentes sectores productivos: una revisión sistemática de la literatura / Perception of musculoskeletal disorders and RULA method application in different productive sectors: a systematic review of literatura

RESUMEN Introducción: Los desórdenes musculoesqueléticos (DME) constituyen una de las principales causas de enfermedad relacionadas con el trabajo. Numerosos esfuerzos se han realizado a fin de prevenir su aparición; por tanto, múltiples instrumentos de evaluación ergonómica han sido usados. Esta revisión tiene como objetivo identificar la información disponible en bases de datos sobre evaluación del riesgo biomecánico (RULA) y percepción de DME en trabajadores de diversos sectores económicos (Cuestionario Nórdico), para el periodo 2004-2015. Materiales y Métodos: Se realizó una revisión sistemática de los estudios recientes enfocados en la evaluación del nivel de riesgo ergonómico y percepción de DME. Asimismo, fueron tenidas en cuenta las recomendaciones de la declaración PRISMA, tras obtener los artículos en las bases de datos Science direct, Scopus, Pubmed, Springer link, Embase y Ebsco. 13 estudios que cumplieron con los criterios de selección fueron incluidos; se identificaron dos tipos de estudios: de diagnóstico y de intervención. Resultados: Prevalencias altas en espalda alta-baja, cuello, tronco, hombros, mano/ muñeca y rodilla fueron evidenciadas, siendo el género femenino el más afectado. Conclusiones: Los hallazgos sugieren asociación entre índice de masa corporal, edad (≥ 25 años), antigüedad en el trabajo (≥ 3 años), trabajo por destajo, horas de trabajo diario ≥ 8 horas, número de pacientes atendidos, RULA (nivel 3 y 4) y DME en cuello, tronco, brazos, antebrazos, espalda baja y zonas corporales del grupo B.

ABSTRACT Introduction: Musculoskeletal disorders (MSD) are one of the main causes of work-related diseases; numerous efforts have been made in order to prevent its occurrence. Therefore, multiple ergonomic evaluation instruments have been used. This review aims to identify the available information in databases related to biomechanical risk assessment (RULA) and perception of DME in workers from various economic sectors, period 2004-2015 (Nordic Questionnaire). Materials and Methods: A Systematic review about the recent studies focused on the evaluation of the level of ergonomic risk and perception of DME was performed. The recommendations of the PRISMA statement were taken into account after obtaining the studies from the Science Direct, Scopus, Pubmed, Springer link, Embase and Ebsco databases. 13 studies that complied the selection criteria were included; 2 types of studies were identified: diagnosis and intervention. Results: High prevalence in upper and lower back, neck, trunk, shoulders, hand/wrist, and knee were evidenced, being the female gender the most affected. Conclusions: These findings suggest an association between body mass index, age (≥ 25 years), seniority at work (≥ 3 years), piecework, daily hours of work ≥ 8 hours, number of patients attended, RULA (level 3 And 4) and DME in the neck, trunk, arms, forearms, lower back and group B body areas.

Risk predictors of stroke and mortality after ablation for atrial fibrillation: the California experience 2005-2009.

BACKGROUND: Ablation (ABL) is a second-line therapy for the management of atrial fibrillation (AF). Single-center studies have demonstrated the safety and efficacy of ABL; however, the low event rates render it difficult to assess predictors of major adverse events. OBJECTIVE: The purpose of this study was to determine the population-based incidence of data and risk factors for both stroke <30 days and death after AF ABL. METHODS: Patients (n = 6207) identified as having undergone AF ABL between 2005 and 2009 by the California Ambulatory Surgery Database in 97 nonfederal hospitals in California were linked to the California Patient Discharge Database and to a master death registry. Data from these patients were analyzed for primary outcomes of 30-day death and ischemic stroke. Independent risk factors for these end-points were determined. RESULTS: Mean patient age was 61.9 years, and the majority of the patients were men. Thirty-day mortality and stroke after ABL were 0.39% and 0.61%, respectively. Independent predictors of death were age ≥80 years (odds ratio [OR] 8.2, 95% confidence interval [CI] 1.5-43) and heart failure (OR 9.2, 95% CI 3.0-28). Prior stroke/transient ischemic attack/stroke was the only independent predictor for stroke (OR 6.3, 95% CI 3-13). CONCLUSION: In our large population-based study, we found higher procedure-related mortality but comparable stroke rate after AF ABL than previously reported. Age ≥80 years and heart failure was each independently associated with >8-fold increase in odds of death. The only significant predictor of stroke was prior stroke/transient ischemic attack. These findings may aid in patient selection for AF ABL.

Evaluation of an exercise field test using heart rate monitors to assess cardiorespiratory fitness and heart rate recovery in an asymptomatic population.

PURPOSE: Measures of cardiorespiratory fitness (CRF) and heart rate recovery (HRR) can improve risk stratification for cardiovascular disease, but these measurements are rarely made in asymptomatic individuals due to cost. An exercise field test (EFT) to assess CRF and HRR would be an inexpensive method for cardiovascular disease risk assessment in large populations. This study assessed 1) the predictive accuracy of a 12-minute run/walk EFT for estimating CRF ([Formula: see text]) and 2) the accuracy of HRR measured after an EFT using a heart rate monitor (HRM) in an asymptomatic population. METHODS: Fifty subjects (48% women) ages 18-45 years completed a symptom-limited exercise tolerance test (ETT) (Bruce protocol) and an EFT on separate days. During the ETT, [Formula: see text] was measured by a metabolic cart, and heart rate was measured continuously by a HRM and a metabolic cart. RESULTS: EFT distance and sex independently predicted[Formula: see text]. The average absolute difference between observed and predicted [Formula: see text] was 0.26 ± 3.27 ml·kg-1·min-1 for our model compared to 7.55 ± 3.64 ml·kg-1·min-1 for the Cooper model. HRM HRR data were equivalent to respective metabolic cart values during the ETT. HRR at 1 minute post-exercise during ETT compared to the EFT had a moderate correlation (r=0.75, p<0.001). CONCLUSION: A more accurate model to estimate CRF from a 12-minute run/walk EFT was developed, and HRR can be measured using a HRM in an asymptomatic population outside of clinical settings.

Effect of coronary artery disease extent on contemporary outcomes of combined aortic valve replacement and coronary artery bypass graft surgery.

BACKGROUND: Concomitant aortic valve replacement (AVR) and coronary artery bypass graft surgery (CABG) is a common procedure. Whether the extent of coronary artery disease (CAD) influences outcomes of AVR plus CABG is unknown. METHODS: All AVR plus CABG cases from 2008 to 2010 were extracted from the California CABG Outcomes Reporting Program database. Patients with left main coronary artery stenosis greater than 50% or at least three diseased vessels were defined as having extensive CAD, and patients with one or two diseased coronary vessels were defined as having less extensive CAD. Multivariable logistic regression models were developed for predicting major postoperative complications and 30-day mortality. A Cox proportional hazards model was developed to predict the risk of 1-year mortality. RESULTS: Between 2008 and 2010, 6,151 AVR plus CABG were performed in California. Compared with patients with one- or two-vessel CAD, patients with extensive CAD undergoing AVR plus CABG were on average older, more often male, had greater prevalence of multiple comorbidities, and underwent more urgent or emergent operations (all p < 0.05). After adjusting for baseline risk factors, AVR plus CABG with extensive CAD was associated with significantly increased risk of major postoperative complications (adjusted odds ratio, 1.24; 95% confidence interval, 1.10 to 1.40; p = 0.001) but not operative mortality (adjusted odds ratio, 1.00; 95% confidence interval, 0.77 to 1.29; p = 0.978). A Cox proportional hazards model showed that age and other medical comorbidities, but not extensive CAD, were significant risk factors for 1-year mortality. CONCLUSIONS: Compared with AVR plus CABG for one- or two-vessel CAD, AVR plus CABG for left main or three or more vessel CAD had higher observed and risk-adjusted rates of postoperative complications but not operative or 1-year mortality.