As manifestações de ECG do maior surto da doença de Chagas devido a infecção oral na América Latina

FUNDAMENTO: A doença de Chagas afeta mais de 15 milhões de pessoas em todo o mundo. Embora a transmissão vetorial tenha diminuído, a transmissão oral tornou-se relevante. Recentemente, nosso grupo publicou as características clínicas e epidemiológicas do maior surto relatado até hoje da doença de Chagas transmitida oralmente. OBJETIVO: Descrever alterações eletrocardiográficas que ocorrem na população de estudo durante o surto causado pela ingestão de suco de goiaba contaminado. MÉTODOS: Avaliamos 103 casos positivos, dos quais 76 (74%) tinham <18 anos de idade (média das idades: 9,1 ± 3,1 anos) e 27 (26%) tinham >18 anos (média das idades: 46 ± 11,8 anos). Todos os pacientes foram submetidos a avaliações clínicas e ECG. Caso os pacientes apresentassem palpitações ou alterações evidentes do ritmo na linha basal, o monitoramento de ECG ambulatorial seria realizado. RESULTADOS: Um total de 68 casos(66%;53 crianças e15 adultos) apresentaram anormalidades no ECG. Além disso, 69,7% (53/76) daqueles com idade < 18anos e 56% (15/27) daqueles com idade >18 anos apresentaram alguma alteração no ECG(p = ns). Anormalidades de ST-T foram observadas em 37,86% casos (39/103) e arritmias foram evidente sem 28,16% casos(29/103). Alterações de ST ocorreram em 72% daqueles com idade < 18 anos em comparação aos de > 18 anos (p < 0,0001). CONCLUSÃO: Este estudo relata o maior número de casos no mesmo surto de doença de Chagas causada por contaminação oral, com ECGs relatados. As alterações no ECG que sugerem miocardite aguda e arritmias foram as anormalidades encontradas com maior frequência.

Método de musicalización de ECG

La música no només pot emprar-se per a l'evocació de sentiments, sinó també per a la transmissió d'informació. En aquest treball es proposa un mètode, en aquest sentit, basat en una forma general de musicalització que vincula algorítmicament la composició musical i el fenomen que es monitoritza. El procediment que resulta ha estat dissenyat específicament per als electrocardiogrames (ECG). Les composicions musicals generades, ofereixen melodies agradables, en el cas de subjectes sans, que s'alteren notablement i es tornen dissonants si els pacients manifesten determinades enfermetats o disfuncions.

Intraobserver and interobserver variability of ascending aorta diameter measurements as assessed by ECG-gated MDCT : automatic versus manual measurements : P15

Purpose: Revolutionary endovascular treatments are on the verge of being available for management of ascending aortic diseases. Morphometric measurements of the ascending aorta have already been done with ECG-gated MDCT to help such therapeutic development. However the reliability of these measurements remains unknown. The objective of this work was to compare the intraobserver and interobserver variability of CAD (computer aided diagnosis) versus manual measurements in the ascending aorta. Methods and materials: Twenty-six consecutive patients referred for ECG-gated CT thoracic angiography (64-row CT scanner) were evaluated. Measurements of the maximum and minimum ascending aorta diameters at mid-distance between the brachiocephalic artery and the aortic valve were obtained automatically with a commercially available CAD and manually by two observers separately. Both observers repeated the measurements during a different session at least one month after the first measurements. Intraclass coefficients as well the Bland and Altman method were used for comparison between measurements. Two-paired t-test was used to determine the significance of intraobserver and interobserver differences (alpha = 0.05). Results: There is a significant difference between CAD and manual measurements in the maximum diameter (p = 0.004) for the first observer, whereas the difference was significant for minimum diameter between the second observer and the CAD (p <0.001). Interobserver variability showed a weak agreement when measurements were done manually. Intraobserver variability was lower with the CAD compared to the manual measurements (limits of variability: from -0.7 to 0.9 mm for the former and from -1.2 to 1.3 mm for the latter). Conclusion: In order to improve reproductibility of measurements whenever needed, pre- and post-therapeutic management of the ascending aorta may benefit from follow-up done by a unique observer with the help of CAD.

Intraobserver and interobserver variability of ascending aorta diameter as assessed with ECG-gated MDCT: automatic versus manual measurements

Purpose: Recently morphometric measurements of the ascending aorta have been done with ECG-gated MDCT to help the development of future endovascular therapies (TCT) [1]. However, the variability of these measurements remains unknown. It will be interesting to know the impact of CAD (computer aided diagnosis) with automated segmentation of the vessel and automatic measurements of diameter on the management of ascending aorta aneurysms. Methods and Materials: Thirty patients referred for ECG-gated CT thoracic angiography (64-row CT scanner) were evaluated. Measurements of the maximum and minimum ascending aorta diameters were obtained automatically with a commercially available CAD and semi-manually by two observers separately. The CAD algorithms segment the iv-enhanced lumen of the ascending aorta into perpendicular planes along the centreline. The CAD then determines the largest and the smallest diameters. Both observers repeated the automatic measurements and the semimanual measurements during a different session at least one month after the first measurements. The Bland and Altman method was used to study the inter/intraobserver variability. A Wilcoxon signed-rank test was also used to analyse differences between observers. Results: Interobserver variability for semi-manual measurements between the first and second observers was between 1.2 to 1.0 mm for maximal and minimal diameter, respectively. Intraobserver variability of each observer ranged from 0.8 to 1.2 mm, the lowest variability being produced by the more experienced observer. CAD variability could be as low as 0.3 mm, showing that it can perform better than human observers. However, when used in nonoptimal conditions (streak artefacts from contrast in the superior vena cava or weak lumen enhancement), CAD has a variability that can be as high as 0.9 mm, reaching variability of semi-manual measurements. Furthermore, there were significant differences between both observers for maximal and minimal diameter measurements (p<0.001). There was also a significant difference between the first observer and CAD for maximal diameter measurements with the former underestimating the diameter compared to the latter (p<0.001). As for minimal diameters, they were higher when measured by the second observer than when measured by CAD (p<0.001). Neither the difference of mean minimal diameter between the first observer and CAD nor the difference of mean maximal diameter between the second observer and CAD was significant (p=0.20 and 0.06, respectively). Conclusion: CAD algorithms can lessen the variability of diameter measurements in the follow-up of ascending aorta aneurysms. Nevertheless, in non-optimal conditions, it may be necessary to correct manually the measurements. Improvements of the algorithms will help to avoid such a situation.

Simulation des caractéristiques ECG du syndrome de Brugada à l'aide d'un programme de modélisation 3D

Introduction : Le syndrome de Brugada, décrit en 1992 par Pedro et Josep Brugada, est un syndrome cardiaque caractérisé par un sus-décalage particulier du segment ST associé à un bloc de branche droit atypique au niveau des dérivations ECG V1 à V3. Les altérations ECG du syndrome de Brugada sont classifiées en 3 types dont seul le type 1 est diagnostique. Les mécanismes physiopathologiques exacts de ce syndrome sont pour le moment encore controversés. Plusieurs hypothèses sont proposées dans la littérature dont deux principales retiennent l'attention : 1) le modèle du trouble de repolarisation stipule des potentiels d'action réduits en durée et en amplitude liés à un changement de répartition de canaux potassiques 2) le modèle du trouble de dépolarisation spécifie un retard de conduction se traduisant par une dépolarisation retardée. Dans le STEMI, un sus-décalage ST ressemblant à celui du syndrome de Brugada est expliqué par deux théories : 1) le courant de lésion diastolique suggère une élévation du potentiel diastolique transformé artificiellement en sus-décalage ST par les filtres utilisés dans tous les appareils ECG.¦Objectif : Recréer les manifestations ECG du syndrome de Brugada en appliquant les modifications du potentiel d'action des cardiomyocytes rapportées dans la littérature.¦Méthode : Pour ce travail, nous avons utilisé "ECGsim", un simulateur informatique réaliste d'ECG disponible gratuitement sur www.ecgsim.org. Ce programme est basé sur une reconstruction de l'ECG de surface à l'aide de 1500 noeuds représentant chacun les potentiels d'action des ventricules droit et gauche, épicardiques et endocardiques. L'ECG simulé peut être donc vu comme l'intégration de l'ensemble de ces potentiels d'action en tenant compte des propriétés de conductivité des tissus s'interposant entre les électrodes de surface et le coeur. Dans ce programme, nous avons définit trois zones, de taille différente, comprenant la chambre de chasse du ventricule droit. Pour chaque zone, nous avons reproduit les modifications des potentiels d'action citées dans les modèles du trouble de repolarisation et de dépolarisation et des théories de courant de lésion systolique et diastolique. Nous avons utilisé, en plus des douze dérivations habituelles, une électrode positionnée en V2IC3 (i.e. 3ème espace intercostal) sur le thorax virtuel du programme ECGsim.¦Résultats : Pour des raisons techniques, le modèle du trouble de repolarisation n'a pas pu être entièrement réalisée dans ce travail. Le modèle du trouble de dépolarisation ne reproduit pas d'altération de type Brugada mais un bloc de branche droit plus ou moins complet. Le courant de lésion diastolique permet d'obtenir un sus-décalage ST en augmentant le potentiel diastolique épicardique des cardiomyocytes de la chambre de chasse du ventricule droit. Une inversion de l'onde T apparaît lorsque la durée du potentiel d'action est prolongée. L'amplitude du sus-décalage ST dépend de la valeur du potentiel diastolique, de la taille de la lésion et de sa localisation épicardique ou transmurale. Le courant de lésion systolique n'entraîne pas de sus-décalage ST mais accentue l'amplitude de l'onde T.¦Discussion et conclusion : Dans ce travail, l'élévation du potentiel diastolique avec un prolongement de la durée du potentiel d'action est la combinaison qui reproduit le mieux les altérations ECG du Brugada. Une persistance de cellules de type nodal au niveau de la chambre de chasse du ventricule droit pourrait être une explication à ces modifications particulières du potentiel d'action. Le risque d'arythmie dans la Brugada pourrait également être expliqué par une automaticité anormale des cellules de type nodal. Ainsi, des altérations des mécanismes cellulaires impliqués dans le maintien du potentiel diastolique pourraient être présentes dans le syndrome de Brugada, ce qui, à notre connaissance, n'a jamais été rapporté dans la littérature.

Evaluation of two minimally invasive techniques for electroencephalogram recording in wild or freely behaving animals.

Insight into the function of sleep may be gained by studying animals in the ecological context in which sleep evolved. Until recently, technological constraints prevented electroencephalogram (EEG) studies of animals sleeping in the wild. However, the recent development of a small recorder (Neurologger 2) that animals can carry on their head permitted the first recordings of sleep in nature. To facilitate sleep studies in the field and to improve the welfare of experimental animals, herein, we test the feasibility of using minimally invasive surface and subcutaneous electrodes to record the EEG in barn owls. The EEG and behaviour of four adult owls in captivity and of four chicks in a nest box in the field were recorded. We scored a 24-h period for each adult bird for wakefulness, slow-wave sleep (SWS), and rapid-eye movement (REM) sleep using 4 s epochs. Although the quality and stability of the EEG signals recorded via subcutaneous electrodes were higher when compared to surface electrodes, the owls' state was readily identifiable using either electrode type. On average, the four adult owls spent 13.28 h awake, 9.64 h in SWS, and 1.05 h in REM sleep. We demonstrate that minimally invasive methods can be used to measure EEG-defined wakefulness, SWS, and REM sleep in owls and probably other animals.

Ascending aorta measurements as assessed by ECG-gated multi-detector computed tomography : a pilot study to etablish normative values for transcatheters therapies

Rapport de synthèse : Mesures de l'aorte ascendante par scanner synchronisé au rythme cardiaque: une étude pilote pour établir des valeurs normatives dans le cadre des futures thérapies par transcathéter. Objectif : L'objectif de cette étude est d'établir les valeurs morphométriques normatives de l'aorte ascendante à l'aide de l'angiographie par scanner synchronisé au rythme cardiaque, afin d'aider au développement des futurs traitements par transcathéter. Matériels et méthodes : Chez soixante-dix-sept patients (âgé de 22 à 83 ans, âge moyen: 54,7 ans), une angiographie par scanner synchronisé au rythme cardiaque a été réalisée pour évaluation des vaisseaux coronaires. Les examens ont été revus afin d'étudier l'anatomie de la chambre de chasse du ventricule gauche jusqu'au tronc brachio-céphalique droit. A l'aide de programmes de reconstructions multiplanaires et de segmentation automatique, différents diamètres et longueurs considérés comme importants pour les futurs traitements par transcathéter ont été mesurés. Les valeurs sont exprimées en moyennes, médianes, maximums, minimums, écart-types et en coefficients de variation. Les variations de diamètre de l'aorte ascendante durant le cycle cardiaque ont été aussi considérées. Résultats : Le diamètre moyen de la chambre de chasse du ventricule gauche était de 20.3+/-3.4 mm. Au niveau du sinus coronaire de l'aorte, il était de 34.2+/-4.1 mm et au niveau de la jonction sinotubulaire il était de 29.7+/-3.4 mm. Le diamètre moyen de l'aorte ascendante était de 32.7+/-3.8 mm. Le coefficient de variation de ces mesures variait de 12 à 17%. La distance moyenne entre l'insertion proximale des valvules aortiques et le départ du tronc brachio-céphalique droit était de 92.6+/-11.8 mm. La distance moyenne entre l'insertion proximale des valvules aortiques et l'origine de l'artère coronaire proximale était de 12.1+/-3.7 mm avec un coefficient de variation de 31%. La distance moyenne entre les deux ostia coronaires était de 7.2+/-3.1 mm avec un coefficient de variation de 43%. La longueur moyenne du petit arc de l'aorte ascendante entre l'artère coronaire gauche et le tronc brachio-céphalique droit était de 52.9+/-9.5 mm. La longueur moyenne de la continuité fibreuse entre la valve aortique et la valvule mitrale antérieure était de 14.6+/-3.3 mm avec un coefficient de variation de 23%. L'aire moyenne de la valve aortique était de 582.0+/-131.9 mm2. La variation du diamètre antéro-postérieur et transverse de l'aorte ascendante était respectivement de 8.4% et de 7.3%. Conclusion Il existe d'importantes variations inter-individuelles dans les mesures de l'aorte ascendante avec cependant des variations intra-individuelles faibles durant le cycle cardiaque. De ce fait, une approche personnalisée pour chaque patient est recommandée dans la confection des futures endoprothèses de l'aorte ascendante. Le scanner synchronisé au rythme cardiaque jouera un rôle prépondérant dans le bilan préthérapeutique. Abstract : The aim of this study was to provide an insight into normative values of the ascending aorta in regards to novel endovascular procedures using ECG-gated multi-detector CT angiography. Seventy-seven adult patients without ascending aortic abnormalities were evaluated. Measurements at relevant levels of the aortic root and ascending aorta were obtained. Diameter variations of the ascending aorta during cardiac cycle were also considered. Mean diameters (mm) were as follows: LV outflow tract 20.3+/-3.4, coronary sinus 34.2+/-4.1, sinotubular junction 29.7+-3.4 and mid ascending aorta 32.7+/-3.8 with coefficients of variation (CV) ranging from 12 to 17%. Mean distances (mm) were: from the plane passing through the proximal insertions of the aortic valve cusps to the right brachio-cephalic artery (BCA) 92.6111.8, from the plane passing through the proximal insertions of the aortic valve cusps to the proximal coronary ostium 12.1+/-3.7, and between both coronary ostia 7.2+/-3.1, minimal arc of the ascending aorta from left coronary ostium to right BCA 52.9 X9.5, and the fibrous continuity between the aortic valve and the anterior leaflet of the mitral valve 14.óf3.3, CV 13-43%. Mean aortic valve area was 582+-131.9 mm2. The variations of the antero-posterior and transverse diameters of the ascending aorta during the cardiac cycle were 8.4% and 7.3%, respectively. Results showed large inter-individual variations in diameters and distances but with limited intra-individual variations during the cardiac cycle. A personalized approach for planning endovascular devices must be considered.

Electroencephalogram changes during inhalation with nitric oxide in the pediatric intensive care patient--a preliminary report.

OBJECTIVES: Although endogenous nitric oxide (NO) is an excitatory mediator in the central nervous system, inhaled NO is not considered to cause neurologic side effects because of its short half-life. This study was motivated by a recent case report about neurologic symptoms and our own observation of severe electroencephalogram (EEG) abnormalities during NO inhalation. DESIGN: Blind, retrospective analyses of EEGs which were registered before, during, and after NO inhalation. EEG was classified in a 5-point rating system by an independent electroencephalographer who was blinded to the patients' clinical histories. Comparisons were made with the previous evaluation documented at recording. Other EEG-influencing parameters such as oxygen saturation, hemodynamics, electrolytes, and pH were evaluated. SETTING: Pediatric intensive care unit of a tertiary care university children's hospital. PATIENTS: Eleven ventilated, long-term paralyzed, sedated children (1 mo to 14 yrs) who had EEG or clinical assessment before NO treatment and EEG during NO inhalation. They were divided into two groups according to the NO-indication (e.g., congenital heart defect, acute respiratory distress syndrome). MEASUREMENTS AND MAIN RESULTS: All 11 patients had an abnormal EEG during NO inhalation. EEG-controls without NO showed remarkable improvement. EEG abnormalities were background slowing, low voltage, suppression burst (n = 2), and sharp waves (n = 2) independent of patients' age, NO-indication, and other EEG-influencing parameters. CONCLUSIONS: These preliminary data suggest the occurrence of EEG-abnormalities after application of inhaled NO in critically ill children. We found no correlation with other potential EEG-influencing parameters, although clinical state, medication, or hypoxemia might contribute. Comprehensive, prospective, clinical assessment regarding a causal relationship between NO-inhalation and EEG-abnormalities and their clinical importance is needed.

A New Method for ECG Tracking of Persistent Atrial Fibrillation Termination during Stepwise Ablation

Stepwise radiofrequency catheter ablation (step-CA) has become the treatment of choice for the restoration of sinus rhythm (SR) in patients with long-standing persistent atrial fibrillation (pers-AF). Its success rate appears limited as the amount of ablation to achieve long term SR is unknown. Multiple organization indexes (OIs) have been previously developed to track the organization of AF during step-CA, however, with limited success. We report an adaptive method for tracking AF termination (AF-term) based on OIs characterizing the relationship between harmonic components of atrial activity from the surface ECG of AF activity. By computing their relative evolution during the last two steps preceding AF-term, we found that the performance of our OIs was superior to classical indices to track the efficiency of step-CA "en route" to AF-term. Our preliminary results suggest that the gradual synchronization between the fundamental and its first harmonic of AF activity appears as a promising parameter for predicting AF-term during step-CA.

A novel method for automated classification of epileptiform activity in the human electroencephalogram-based on independent component analysis.

Diagnosis of several neurological disorders is based on the detection of typical pathological patterns in the electroencephalogram (EEG). This is a time-consuming task requiring significant training and experience. Automatic detection of these EEG patterns would greatly assist in quantitative analysis and interpretation. We present a method, which allows automatic detection of epileptiform events and discrimination of them from eye blinks, and is based on features derived using a novel application of independent component analysis. The algorithm was trained and cross validated using seven EEGs with epileptiform activity. For epileptiform events with compensation for eyeblinks, the sensitivity was 65 +/- 22% at a specificity of 86 +/- 7% (mean +/- SD). With feature extraction by PCA or classification of raw data, specificity reduced to 76 and 74%, respectively, for the same sensitivity. On exactly the same data, the commercially available software Reveal had a maximum sensitivity of 30% and concurrent specificity of 77%. Our algorithm performed well at detecting epileptiform events in this preliminary test and offers a flexible tool that is intended to be generalized to the simultaneous classification of many waveforms in the EEG.

ECG interpretation during the acute phase of coronary syndromes: in need of improvement?

QUESTION UNDER STUDY: Emergency room (ER) interpretation of the ECG is critical to assessment of patients with acute coronary syndromes (ACS). Our aim was to assess its reliability in our institution, a tertiary teaching hospital. METHODS: Over a 6-month period all consecutive patients admitted for ACS were included in the study. ECG interpretation by emergency physicians (EPs) was recorded on a preformatted sheet and compared with the interpretation of two specialist physicians (SPs). Discrepancies between the 2 specialists were resolved by an ECG specialist. RESULTS: Over the 6-month period, 692 consecutive patients were admitted with suspected ACS. ECG interpretation was available in 641 cases (93%). Concordance between SPs was 87%. Interpretation of normality or abnormality of the ECG was concordant between EPs and SPs in 475 cases (74%, kappa = 0.51). Interpretation of ischaemic modifications was concordant in 69% of cases, and as many ST segment elevations were unrecognised as overdiagnosed (5% each). The same findings occurred for ST segment depressions and negative T waves (12% each). CONCLUSIONS: Interpretation of the ECG recorded during ACS by 2 SPs was discrepant in 13% of cases. Similarly, EP interpretation was discrepant from SP interpretation in 25% of cases, equally distributed between over- and underdiagnosing of ischaemic changes. The clinical implications and impact of medical education on ECG interpretation require further study.