Evaluation of electrocardiographic P wave parameters in predicting long-term atrial fibrillation in patients with acute ischemic stroke / Avaliação dos parâmetros eletrocardiográficos da onda P na predição de fibrilação atrial de longa duração em pacientes com acidente vascular cerebral isquêmico agudo

Abstract Background Electrocardiographic parameters, such as P wave peak time (PWPT), P wave duration (PWD), and P wave amplitude in lead DI, have been utilized to assess left atrial anomalies linked to the development of atrial fibrillation (AF) in different cohort settings. Objective To compare electrocardiographic parameters, such as P waves, in predicting long-term AF risk in acute ischemic stroke cases. Methods The data of 231 consecutive acute ischemic stroke cases were retrospectively collected. Two independent cardiologists interpreted the electrocardiography recordings for PWPT, PWD, and P wave amplitude in lead DI. The median follow-up study period was 16 (interquartile range [IQR]: 11-24) months. Results In total, AF was detected in 43 (18.6%) cases. All studied P wave parameters were found to be statistically significant in cases with AF. Based on multivariable logistic regression analysis, dementia, left atrium volume index, PWD (razão de chances [RC]: 1.11; 95% confidence interval [CI]: 1.058-1.184; p = 0.003), PWPT in lead DII (RC: 1.030; 95%CI: 1.010-1.050; p = 0.003), and advanced interatrial block morphology were independent predictors of long-term AF. P wave duration had the highest area under the curve value, sensitivity, and specificity for long-term AF in such cases compared with the other P wave parameters. Conclusions Our head-to-head comparison of well-known P wave parameters demonstrated that PWD might be the most useful P wave parameter for long-term AF in acute ischemic stroke cases.

Resumo Antecedentes Parâmetros eletrocardiográficos, como tempo de pico da onda P (PWPT, na sigla em inglês), duração da onda P (PWD, na sigla em inglês) e amplitude da onda P na derivação DI, têm sido utilizados para avaliar anomalias atriais esquerdas ligadas ao desenvolvimento de fibrilação atrial (FA) em diferentes cenários de coortes. Objetivo Comparar os parâmetros eletrocardiográficos destas ondas P na predição do risco de FA de longo prazo em casos de acidente vascular cerebral (AVC) isquêmico agudo. Métodos Os dados de 231 casos consecutivos de AVC isquêmico agudo foram coletados retrospectivamente. Dois cardiologistas independentes interpretaram os registros eletrocardiográficos para PWPT, PWD e amplitude da onda P na derivação DI. O período médio do estudo de acompanhamento foi de 16 (intervalo interquartil [IQR, na sigla em inglês]: 11-24) meses. Resultados No total, FA foi detectada em 43 (18,6%) casos. Todos os parâmetros da onda P estudados foram considerados estatisticamente significativos nos casos com FA. Com base na análise de regressão logística multivariável, demência, índice de volume do átrio esquerdo, PWD (razão de chances [RC]: 1,112; intervalo de confiança [IC] 95%: 1,058-1,184; p = 0,003), PWPT na derivação DII (RC: 1,030; IC95%: 1,010-1,050; p = 0,003) e avançada morfologia do bloqueio interatrial foram preditores independentes de FA de longo prazo. A PWD teve a maior área sob o valor da curva, sensibilidade e especificidade para FA de longo prazo em tais casos em comparação com os outros parâmetros da onda P. Conclusões Nossa comparação direta de parâmetros da onda P bem conhecidos demonstrou que a PWD pode ser o parâmetro da onda P mais útil para FA de longa duração em casos de AVC isquêmico agudo.

Síndrome de Bayés en el perioperatorio / Bayes syndrome in the perioperative period

Resumen: Los bloqueos auriculares se caracterizan por alteraciones en la conducción secundarias a un retardo o bloqueo en el haz de Bachmann. El Dr. Antonio Bayés de Luna fue uno de los primeros en describir de manera extensa esta entidad a partir de 1979, clasificándolo en inter- e intraauriculares. El bloqueo interauricular se caracteriza en el electrocardiograma (ECG) por onda P con duración mayor a 120 mseg y que presentan morfología bimodal, especialmente en las derivaciones DI, DII, aVL y en las derivaciones inferiores. Existen varios tipos y grados de bloqueo interauricular relacionados a la magnitud del deterioro de la conducción entre las aurículas. Este bloqueo se asocia con frecuencia a taquiarritmias, en especial fibrilación auricular. El manejo incluye antiarrítmicos, anticoagulantes y, en casos especiales, terapia de resincronización auricular. El objetivo de este trabajo es enfatizar en la importancia de la evaluación de la onda P y de los bloqueos interauriculares en el período perioperatorio.

Abstract: The interatrial block is an auricular conduction abnormality secondary to delay or block through the Bachmann's bundle. Dr. Antonio Bayés de Luna was the first who provided a clear description of atrial conduction block in 1979, classifying them into either inter- and -intra atrial. The interatrial block is expressed in the electrocardiogram (ECG) by the presence of P-wave duration that equals or exceeds 120 mseg and presents usually a bimodal morphology, especially in leads I, II, aVL and inferior leads. There are different types of interatrial block related to deterioration of conduction between the right and left atrium. It was demonstrated that this type of block is very frequently accompanied by paroxysmal atrial arrhythmia, especially atrial fibrillation. Current medical therapies included anti-arrythmic, anticoagulation and in special cases atrial resynchronization. The aim of this paper is to emphasize the importance of the evaluation of P wave and interatrial blocks in the perioperative period.

Rol de la morfología y dispersión de la onda P en la predicción de fibrilación auricular

RESUMEN Las características anisotrópicas ocasionadas por un miocardio auricular patológico pueden jugar un papel importante en la creación de circuitos de reentrada al causar propagación no homogénea y discontinua del impulso en el miocardio auricular. Este miocardio auricular alterado puede generar bloqueo unidireccional, retraso de la conducción y ritmos auriculares reentrantes. En estas condiciones la onda P del electrocardiograma (ECG) puede mostrar alteraciones que pueden asociarse con arritmias auriculares y fibrilación auricular (FA). La dispersión de la onda P (DP) se considera un marcador no invasivo del ECG para el remodelado auricular y es predictor sensible y específico del desarrollo de FA. Se ha demostrado que el aumento de la duración de la onda P y la DP reflejan la prolongación del tiempo de conducción auricular dentro de la aurícula derecha y entre ambas aurículas, y una propagación auricular no homogénea y discontinua de los impulsos sinusales. Un valor de corte de 40 ms de la DP demostró tener una sensibilidad del 83%, una especificidad del 85% y un valor predictivo positivo del 89% para la identificación de pacientes con antecedentes de FA paroxística aislada. Los pacientes con alteración de la morfología de la onda P y dispersión de la onda P en el ECG tienen una gran susceptibilidad a desarrollar FA porque poseen electrogramas endocárdicos auriculares anormalmente prolongados y fraccionados, una duración de onda P significativamente mayor, un tiempo de conducción intraauricular e interauricular significativamente más largo, y una mayor incidencia de inducción de fibrilación auricular sostenida.

ABSTRACT The anisotropic characteristics caused by a pathological atrial myocardium can play an important role in the creation of reentry circuits by causing discontinuous and inhomogeneous impulse propagation in the atrial myocardium. This altered atrial myocardium can lead to unidirectional block, conduction delay, and reentrant atrial rhythms. Under these conditions, the P wave of the electrocardiogram (ECG) can demonstrate alterations that can be associated with atrial arrhythmias and atrial fibrillation (AF). The P-wave dispersion (PD) is considered a non-invasive ECG marker for atrial remodeling and is a sensitive and specific predictor of the development of AF. Increased P wave duration and PD have been shown to reflect prolonged atrial conduction time within the right atrium and between both atria, and discontinuous, inhomogeneous atrial propagation of sinus impulses. A cutoff value of 40 ms for PD was shown to have a sensitivity of 83%, a specificity of 85%, and a positive predictive value of 89% for the identification of patients with a history of isolated paroxysmal AF. Patients with abnormal P wave morphology and P wave dispersion on the ECG are highly susceptible to developing AF because they have abnormally prolonged and fractionated atrial endocardial electrograms, significantly longer P wave duration, and significantly longer intra-atrial and inter-atrial conduction time, and a higher incidence of sustained atrial fibrillation induction.

Duración de la onda P en las 12 derivaciones del electrocardiograma y su relación con el tiempo de conducción interauricular en pacientes con taquicardias paroxísticas supraventriculares / P wave duration in the 12 leads of the electrocardiogram and its relationship with interatrial conduction time in patients with paroxysmal supraventricular tachycardias

RESUMEN Introducción: Existen algunos estudios que relacionan parámetros de la onda P con diferentes tiempos de conducción auricular, pero no se han realizado teniendo en cuenta a cada derivación del electrocardiograma. Objetivo: Determinar la duración de la onda P (Pdur) en las 12 derivaciones y relacionarlas con el tiempo de conducción interauricular. Método: Estudio de corte transversal en 153 pacientes adultos con diagnóstico confirmado de taquicardia por reentrada intranodal (TRIN) o vías accesorias mediante estudio electrofisiológico invasivo. Resultados: Al comparar la Pdur entre sustratos arrítmicos por cada derivación, no existieron diferencias significativas, excepto en V6. En las derivaciones DII, DIII, aVR, aVF, V1 y de V3-V6 la Pdur se correlacionó con el tiempo de conducción interauricular en ambos sustratos arrítmicos. En el análisis multivariado, la Pdur constituyó un predictor independiente de tiempos de conducción interauricular ≥ 95 percentil, en las derivaciones de cara inferior y en V3, V5 y V6. Se observaron altos valores del área bajo la curva de la Característica Operativa del Receptor en las derivaciones DII (0,950; p<0,001), DIII (0,850; p<0,001) y V5 (0,891; p<0,001). Conclusiones: No existen diferencias por derivación en la Pdur al comparar casos con TRIN y vías accesorias, excepto en V6. La mayoría de las derivaciones se correlacionaron con el tiempo de conducción interauricular. La Pdur fue un predictor independiente de tiempos de conducción interauricular ≥ 95 percentil. La derivación DII presenta la mayor capacidad discriminativa para encontrar valores prolongados del tiempo de conducción interauricular.

ABSTRACT Introduction: Although some studies relate P wave parameters to different atrial conduction times, they do not consider each electrocardiogram lead separately. Objective: To determine the duration of P wave (Pdur) in the 12 leads of the electrocardiogram and relate it to the interatrial conduction time. Method: We conducted a cross-sectional study in 153 adult patients with confirmed diagnosis of atrioventricular nodal reentry tachycardia (AVNRT) or accessory pathways by invasive electrophysiological study. Results: When comparing the Pdur between arrhythmic substrates by each lead, no significant differences were found, except for V6. In leads II, III, aVR, aVF, V1 and V3-V6, Pdur was correlated with the interatrial conduction time in both arrhythmic substrates. In our multivariate analysis, the Pdur was an independent predictor of interatrial conduction times ≥ 95 percentile in inferior wall leads and in V3, V5 and V6. High values of the area under the receiver operating characteristic curve were observed in II (0.950; p<0.001), III (0.850; p<0.001) and V5 (0.891; p<0.001) leads. Conclusions: The Pdur showed no difference by leads when comparing cases with AVNRT and accessory pathways, except for V6. Most of the leads were correlated with the interatrial conduction time; Pdur was an independent predictor of interatrial conduction times ≥ 95 percentile. Lead II has the greatest discriminatory ability to find prolonged values of interatrial conduction time.

Comparative assessment of electrocardiographic parameters of some birds in ilorin-an essential diagnostic tool

Introduction: Cardiovascular disease is an important cause of death in birds. Spontaneous turkey cardiomyopathy (STC; round heart), ruptured aorta and sudden death account for over 50% in avians. The diagnosis is usually based on history and gross examination. This work was designed to assess the electrocardiographic parameters of various birds as alternative/additional means of clinical diagnosis. Objective: of this study was to identify every aspect of the Lead II ECG wave form. The electrocardiogram is a useful tool in avian medicine as it can be utilized to measure heart rate and to detect arrhythmias, cardiac chamber enlargement, and electrical conductance abnormalities. Methods: EDAN 10 Veterinary electrocardiographic equipment made in China; with a 200 mm/s paper speed and a sensitivity of 100 mm/mV was used to measure the electrocardiographic. The five alligator clip electrodes were fixed directly to the skin under the feather- on the forearms (muscular part of the wing), on the hind limbs above the stifle joint, and the heart as described earlier by Azeez et al, (2017). Birds were placed on lateral recumbency. The EDAN was connected to the laptop and information about each bird was recorded and saved. Birds considered include Broilers, Domestic duck, White geese, Chinese geese, Laying birds (chicken), point of lay birds and Turkey. They were all carefully restrained. 5 birds from each group were used. Results: The ECG exhibited positive P wave, inverted (Q)RS and positive T wave in all of them. S-S interval was regular in turkey and duck, irregular in chicken and Chinese geese. The PR interval in the Laying birds and Broilers were very longer with overlap by QRS. The (Q)RS was shorter (29-44ms)in the chicken with very short amplitude, longer (50-65ms)in turkey and duck with longer amplitude. No significant difference in the QRS within the groups. QT interval was longer in turkey, geese and duck (297-456ms) but shorter in chicken. Conclusions: Electrocardiography is a useful diagnostic tool in birds. However, while interpreting electrocardiographic, Clinicians should always consider history, clinical findings and laboratory results before final diagnosis. More emphasis should be place on use of electrocardiographic by Veterinarians and Clinicians in handling cases of cardiovascular issues in birds.

Introducción: Las enfermedades cardiovasculares son una importante causa de muerte entre las aves. La miocardiopatía espontánea del pavo (MEP; corazón redondo), la ruptura de la aorta y la muerte súbita representan más del 50 % de las muertes aviares. Generalmente el diagnóstico se basa en los antecedentes y en un examen general. En el presente estudio se evalúan los parámetros electrocardiográficos de un grupo de aves como medios alternativos / adicionales del diagnóstico clínico. Objetivo: Identificar cada aspecto de la forma de onda del ECG de derivación II. El electrocardiograma es una herramienta útil en la medicina aviar, ya que puede usarse para medir la frecuencia cardíaca y para detectar arritmias, agrandamiento de la cámara cardíaca y anomalías de la conductancia eléctrica. Métodos: Los parámetros electrocardiográficos se midieron con un electrocardiógrafo veterinario EDAN 10 fabricado en China, con una velocidad del papel de 200 mm/s y una sensibilidad de 100 mm/mV. Los cinco electrodos de presilla tipo cocodrilo fueron fijados directamente a la piel bajo las plumas en el área del antebrazo (parte muscular del ala), en las extremidades posteriores por encima de la babada, y en el corazón según se describe en Azeez et al (2017). Las aves fueron colocadas en posición reclinada lateral. El EDAN se conectó a una laptop para registrar y guardar la información sobre cada ave. Las aves del estudio eran pollos de engorde, patos domésticos, gansos blancos, gansos chinos, gallinas ponedoras, aves listas para empezar a poner y pavos. Todas fueron sujetadas firmemente. Se utilizaron cinco aves de cada grupo. Resultados: El ECG mostró una onda P positiva, un (Q)RS invertido y una onda T positiva en todas ellas. El intervalo S-S fue regular en pavos y patos, e irregular en pollos y gansos chinos. El intervalo PR fue mucho más largo en las ponedoras y los pollos de engorde, con superposición por el QRS. El (Q)RS fue más corto (29-44 ms) en los pollos con una amplitud muy corta, y más largo (50-65 ms) en pavos y patos con una amplitud más larga. No se hallaron diferencias significativas en el QRS dentro de los grupos. El intervalo QT fue más largo en los pavos, gansos y patos (297-456 ms) pero más corto en los pollos. Conclusiones: La electrocardiografía es una útil herramienta para el diagnóstico de las aves. Sin embargo, al interpretar la información electrocardiográfica, siempre se deben tener en cuenta los antecedentes, los hallazgos clínicos y los resultados de laboratorio antes de emitir el diagnóstico definitivo. Se debe hacer más hincapié en el uso de la electrocardiografía por parte de los veterinarios y los médicos al tratar casos de problemas cardiovasculares en las aves.

P wave dispersion in obese dogs with and without mitral valve disease / Dispersão da onda P em cães obesos apresentando ou não doença valvar mitral

ABSTRACT: Pwave dispersion (Pd) is an electrocardiographic index defined as the difference between the minimum and maximum Pwave duration in multiple leads. The augmentation of Pd reflects the discontinuous and inhomogeneous atrial depolarization resulting from cardiac and non-cardiac conditions. In humans, an increased Pd is associated with the development of cardiac arrhythmias, particularly atrial fibrillation. To investigate Pd in obese dogs, we enrolled 76 dogs, which were classified in four distinct categories according to body condition and the existance of valve insufficiency: obese dogs (O), dogs with both obesity and cardiac disease (O+CD), lean dogs with cardiac disease (CD) and healthy controls (H). To be included in the study, all dogs underwent an electrocardiographic and echocardiographic assessment. We reported significantly higher Pd in the animals included in categories O, O+CD and CD (18.0±7.6ms, 16.1±4.4ms, 12.1±4.3ms, respectively) as compared to the healthy subjects (7.3±2.2ms). Also, significant correlations between Pd and both the body mass index and body fat percentage were documented for the obese dogs. However, no association between Pd and LA/Ao could be identified in patients belonging to the O, O+CD and H categories. Thus, we have demonstrated that obese dogs, regardless of their valvular competency status, present high Pd values, suggesting an impaired propagation of atrial electrical impulse.

RESUMO: A dispersão da onda P (Pd) é um índice eletrocardiográfico definido como a diferença entre as durações máxima e mínima da onda P em múltiplas derivações. O aumento da Pd reflete a despolarização discontínua e não homogênea resultante de condições cardíacas e não cardíacas. Em seres humanos, uma Pdaumentada está associada com o desenvolvimento de arritmias cardíacas, particularmente fibrilação atrial. Com o intuito de investigar a Pd em cães obesos, foram selecionados 76 cães, os quais foram classificados em quatro categorias distintas, de acordo com sua condição corporal e a existência de insuficiência valvar: cães obesos (O), cães com obesidade e doença cardíaca (O+CD), cães magros com doença cardíaca (CD) e cães saudáveis usados como controle (H). Uma vez selecionados para o estudo, todos os cães foram submetidos às avaliações eletrocardiográfica e ecocardiográfica. Os resultados mostraram maior Pd nos animais pertencentes aos grupos O, O+CD e CD (18.0±7.6ms, 16,1±4,4ms, 12,1±4,3ms, respectivamente) quando comparados aos cães saudáveis (7.3±2.2ms). Além disso, foram verificadas correlações significativas entre Pde tanto o índice de massa corporal quanto o percentual de gordura corporal nos cães obesos. Entretanto, não se identificou associação entre Pd e a relação AE/Ao nos pacientes das categorias O, O+CD e H. Dessa forma, foi possível demonstrar que cães obesos, independentemente do estado de competência valvar, apresentam Pd elevada, fato que sugere comprometimento da propagação do impulso elétrico atrial.

Levels of uric acid and increased diastolic blood pressure: Risk factors for atrial fibrillation in patients older than 60 years / Niveles de ácido úrico y presión arterial diastólica elevada: factores de riesgo de fibrilación atrial en pacientes mayores de 60 años

Summary Objective: To characterize the maximum P-wave duration (Pmax) and P-wave dispersion (PWD) according to blood pressure (BP) and uric acid (UA) levels in geriatric patients. Method: An analytical study was performed in 83 patients aged over 60 years treated at the Family Medical Office 5 of the Aracelio Rodríguez Castellón Polyclinic, in Cienfuegos, Cuba between January and December 2015. The sample was divided into two groups (patients with hyperuricemia and patients with normal UA levels). Results: We found a linear and significant correlation between diastolic BP and Pmax in patients with hyperuricemia (r=0.695; p=0.026), but not in patients with normal UA (r=0.048; p=0.757). A linear and significant correlation was demonstrated between diastolic BP and PWD in patients with hyperuricemia (r=0.657; p=0.039), but not in patients with normal UA (r=0.054; p=0.730). Conclusion: There is correlation between diastolic BP and Pmax plus PWD in elderly patients with hyperuricemia.

Resumen Objetivo: Caracterizar la máxima duración de la onda P (Pmáx) y la dispersión de la onda P (DP) según las cifras de tensión arterial (TA) y los niveles de ácido úrico en pacientes geriátricos. Método: Se realizó un estudio analítico en 83 pacientes mayores de 60 años pertenecientes al Consultorio Médico de la Familia 5 del Policlínico Aracelio Rodríguez Castellón, Cienfuegos, Cuba entre enero y diciembre de 2015. La muestra se dividió en dos grupos (pacientes con hiperuricemia y pacientes con AU normal). Resultados: Existe correlación lineal y significativa entre la tensión arterial diastólica y la Pmáx en los pacientes con hiperuricemia (r=0,695; p=0,026), mas no en los pacientes con AU normal (r=0,048; p=0,757). Se demuestra correlación lineal y significativa entre la tensión diastólica y la DP en los pacientes con hiperuricemia (r=0,657; p=0,039), aunque no en los pacientes con AU normal (r=0,054; p=0,730), respectivamente. Conclusión: Existe correlación entre la Pmáx y la DP y las cifras de tensión arterial diastólica en pacientes geriátricos con hiperuricemia.

Dispersión de la onda P incrementada en niños dependiendo de la presión arterial, del peso, talla, de la estructura y función cardiaca / P wave dispersion increased in childhood depending on blood pressure, weight, height, and cardiac structure and function

Introducción: La dispersión de onda P incrementada se señala como predictor de fibrilación auricular, existiendo asociación entre hipertensión arterial, dispersión de onda P y variables ecocardiográficas y constitucionales. Estas relaciones han sido poco estudiadas en pediatría. Objetivo: Determinar la relación de la dispersión de la onda P con presión arterial, variables ecocardiográficas y constitucionales, y determinar las variables más influyentes en los incrementos de la dispersión de la onda P en pediatría. Método: Se estudiaron en el marco del proyecto PROCDEC II niños de 8 a 11 años. Se midió presión arterial, se realizó electrocardiograma de superficie y ecocardiograma. Resultados: Los valores de media del índice de masa ventricular izquierda para normotensos (25.91 ± 5.96 g/m2.7) e hipertensos (30.34 ± 8.48 g/m2.7) mostraron diferencias significativas (p = 0.000). Un 50.38% de prehipertensos más hipertensos presentan índice de masa ventricular normal y dispersión de la onda P incrementada versus normotensos (13.36%). La presión arterial media, la duración de la onda A, el peso y la talla presentan un valor de r = 0.88 al relacionarlo de forma múltiple con la dispersión de la onda P. Conclusiones: El índice de masa ventricular y la dispersión de la onda P demuestran ser mayores en pacientes prehipertensos e hipertensos que en normotensos. Se encontraron pacientes prehipertensos e hipertensos con índice de masa ventricular normal y dispersión de la onda P incrementada. Las variables que demostraron mayor influencia en los aumentos de la dispersión de la onda P fueron la presión arterial media, la duración de la onda A del flujo mitral, el peso y la talla.

Introduction: Increased P wave dispersion are identified as a predictor of atrial fibrillation. There are associations between hypertension, P wave dispersion, constitutional and echocardiographic variables. These relationships have been scarcely studied in pediatrics. Objective: The aim of this study was to determine the relationship between P wave dispersion, blood pressure, echocardiographic and constitutional variables, and determine the most influential variables on P wave dispersion increases in pediatrics. Method: In the frame of the PROCDEC II project, children from 8 to 11 years old, without known heart conditions were studied. Arterial blood pressure was measured in all the children; a 12-lead surface electrocardiogram and an echocardiogram were done as well. Results: Left ventricular mass index mean values for normotensive (25.91 ± 5.96 g/m2.7) and hypertensive (30.34 ± 8.48 g/m2.7) showed significant differences P = .000. When we add prehypertensive and hypertensive there are 50.38% with normal left ventricular mass index and P wave dispersion was increased versus 13.36% of normotensive. Multiple regression demonstrated that the mean blood pressure, duration of A wave of mitral inflow, weight and height have a value of r = 0.88 as related to P wave dispersion. Conclusions: P wave dispersion is increased in pre- and hypertensive children compared to normotensive. There are pre- and hypertensive patients with normal left ventricular mass index and increased P wave dispersion. Mean arterial pressure, duration of the A wave of mitral inflow, weight and height are the variables with the highest influence on increased P wave dispersion.

Índices de onda P na predição de recorrência de fibrilação atrial após isolamento da veia pulmonar / P wave indices to predict atrial fibrillation recurrences post pulmonary vein isolation

FUNDAMENTO: Índices de ondas P são marcadores interessantes para prever recorrências de fibrilação atrial (FA) pós ablação. OBJETIVO: Esse estudo avalia o valor dos índices de onda P para prever recorrências após isolamento da veia pulmonar (IVP) em pacientes com fibrilação atrial paroxística. MÉTODOS: Foram selecionados 198 pacientes (57 ± 8 anos, 150 homens) com FA paroxística sintomática refratária a medicamentos submetidos ao IVP em nosso hospital. Um eletrocardiograma de 12 derivações foi utilizado para medir a duração da onda P na derivação II, a força terminal de P (FTP) na derivação V1, o eixo e a dispersão da onda P. RESULTADOS: No acompanhamento de 9 ± 3 meses, as recorrências ocorreram em 60 (30,3%) pacientes. Os pacientes que apresentaram recorrência de FA tiveram maior duração média de onda P (122,9 ± 10,3 versus 104,3 ± 14,2 ms, p < 0,001), maior dispersão da onda P (40,7 ± 1,7 ms vs 36,6 ± 3,2 ms, p < 0,001). A duração da onda P > 125 ms apresenta 60% de sensibilidade, especificidade de 90%, valor preditivo positivo (VPP) de 72% e valor preditivo negativo (VPN) de 83,7%, enquanto a dispersão da onda P > 40 ms tem 78% de sensibilidade, 67% de especificidade, PPV 51% e VPN de 87,6%. 48/66 (72,7%) dos pacientes com FTP < -0,04 mm/segundo vs 12/132 (9%) com FTP > -0,04 mm/segundo tiveram recorrência de FA (p < 0,001). O eixo da onda P não diferiu entre os dois grupos. Na análise multivariada, os índices da onda P não foram independentes do tamanho do átrio esquerdo e da idade. CONCLUSÕES: A duração da onda P > 125 ms, a dispersão da onda P > 40 ms e FTP em V1 < -0,04 mm/sec são bons preditores clínicos das recorrências de FA pós IVP em pacientes com fibrilação atrial paroxística; contudo, eles não foram independentes do tamanho do átrio esquerdo e da idade.

BACKGROUND: P-wave indices are appealing markers for predicting atrial fibrillation (AF) recurrences post ablation. OBJECTIVE: This study evaluates the value of P wave indices to predict recurrences post pulmonary vein isolation (PVI) in patients with paroxysmal AF. METHODS: We selected 198 patients (57 ± 8 years, 150 males) with symptomatic drug-refractory paroxysmal AF undergoing PVI in our hospital. A 12-lead electrocardiogram was used to measure P wave duration in lead II, P wave terminal force (PWTF) in lead V1, P wave axis and dispersion. RESULTS: During a follow-up of 9 ± 3 months, recurrences occurred in 60 (30.3%) patients. The patients that had AF recurrence had longer mean P wave duration (122.9 ± 10.3 vs 104.3 ± 14.2 ms, p < 0.001), larger P wave dispersion (40.7 ± 1.7 ms vs 36.6 ± 3.2 ms, p < 0.001). P wave duration > 125 ms has 60% sensitivity, 90% specificity, positive predictive value (PPV) of 72% and negative predictive value (NPV) of 83.7%, whereas P wave dispersion > 40 ms has 78% sensitivity, 67% specificity, PPV of 51% and NPV of 87.6% 48/66 (72.7%) patients with PWTF < -0.04 mm/second vs12/132(9%) with PWTF > -0.04 mm/second showed recurrence of AF (p < 0.001). P wave axis was not different between two groups. On multivariate analysis, P wave indices were not independent from left atrial size and age. CONCLUSIONS: P wave duration > 125 ms, P wave dispersion > 40 ms and PWTF in V1 < -0.04 mm/sec are good clinical predictors of AF recurrences post PVI in patients with paroxysmal atrial fibrillation; however they were not independent from left atrial size and age.

Dependence of P-wave dispersion on mean arterial pressure as an independent hemodynamic variable in school children / Dependencia de la dispersión de la onda P en la presión arterial media como variable hemodinámica independiente en niños en edad escolar

Abstract Introduction: The relationship between diastolic dysfunction and P-wave dispersion (PWD) in the electrocardiogram has been studied for some time. In this regard, echocardiography is emerging as a diagnostic tool to improve risk stratification for mild hypertension. Objective: To determine the dependence of PWD on the electrocardiogram and on echocardiographic variables in a pediatric population. Methods: Five hundred and fifteen children from three elementary schools were studiedfrom a total of 565 children. Those whose parents did not want them to take part in the study, as well as those with known congenital diseases, were excluded. Tests including 12-lead surface ECGs and 4 blood pressure (BP) measurements were performed. Maximum and minimum P-values were measured, and the PWD on the electrocardiogram was calculated. Echocardiography for structural measurements and the pulsed Doppler of mitral flow were also performed. Results: A significant correlation in statistical variables was found between PWD and mean BP for pre-hypertensive and hypertensive children, i.e., r= 0.32, p <0.01 and r= 0.33, p <0.01, respectively. There was a significant correlation found between PWD and the left atrial area (r= 0.45 and p <0.01). Conclusions: We highlight the dependency between PWD, the electrocardiogram and mean blood pressure. We also draw attention to the dependence of PWD on the left atrial area. This result provides an explanation for earlier changes in atrial electrophysiological and hemodynamic characteristics in pediatric patients.

Resumen Introducción: La relación entre la disfunción diastólica y la dispersión de la onda P (PWD) en el electrocardiograma se ha estudiado durante algún tiempo. En este sentido, la ecocardiografía se está convirtiendo en una herramienta de diagnóstico para mejorar la estratificación de riesgo en la hipertensión leve. Objetivo: Determinar la dependencia de las PWD en el electrocardiograma de las variables ecocardiográficas en una población pediátrica. Métodos: De un total de 565 niños de tres escuelas primarias, fueron estudiados 515 niños. Fueron excluidos del estudio, aquellos niños cuyos padres se negaron a participar, y los niños con enfermedades congénitas conocidas. Se les realizó electrocardiograma de superficie de 12 derivaciones y se realizaron 4 tomas de presión arterial. Fueron medidas las ondas P del electrocardiograma y calculada su dispersión. Se realizó ecocardiografía para medidas estructurales y Doppler pulsado del flujo mitral. Resultados Se demuestra correlación significativa entre la PWD y la tensión arterial media para prehipertensos e hipertensos r= 0.32, p <0.01 y r= 0.33 p <0.01, respectivamente. Existe una correlación significativa entre PWD y área de la aurícula izquierda (r= 0.45 y p <0.01). Conclusiones: Existe dependencia de la dispersión de la onda P del electrocardiograma de la tensión arterial media. Se demostró dependencia de la dispersión de la onda P sobre el área auricular izquierda. Este resultado sugiere la existencia de cambios en las características electrofisiológicas auriculares y cambios hemodinámicos en la población pediátrica estudiada.

Eletrocardiografia computadorizada em cães: estudo comparativo / Computerized electrocardiography in dogs: a comparative study

Computerized electrocardiography (C-EKG) has been more frequently used in Veterinary Medicine. Many equipment models are available for this purpose. Due to possible device sensitivity and reproducibility differences during examination, the main goal of this study was to compare electrocardiographic parameters of dogs using two different C-EKG systems: Wincardio Micromed® (WIN) and TEB ECGPC® (TEB). Forty two healthy male and female dogs of different breeds (Cocker Spaniel, Dachshund, Labrador, Pinscher, Pitbull Terrier, Poodle, Schnauzer, Shih Tzu, Yorkshire and mongrel dogs), with age between 4 months and 16 years old were grouped according to weight and evaluated by both systems. The electrocardiographic measurements were performed on DII lead for both systems. The study showed that the TEB system was more sensitive for measurement of P wave and QRS complex duration, while the WIN system showed more sensitivity for the measurements of amplitude of the same parameters. The larger animals (26-37kg) showed greater variance in the measurements of P wave and QRS complex amplitude and duration than the groups of medium (14-25kg) or smaller (3-13kg) dogs. These differences must be considered when using diverse computerized electrocardiography systems to perform measurements due to the possibility of erratic interpretation of the results between veterinary medicine services.

O método de eletrocardiografia computadorizada (ECG-C) vem sendo crescentemente difundido na medicina veterinária, havendo atualmente diversas marcas e modelos de eletrocardiógrafos disponíveis no mercado. Diante da possibilidade de diferenças na sensibilidade e na reprodutibilidade das medidas obtidas nos traçados, o presente estudo teve como objetivo comparar os parâmetros eletrocardiográficos de cães, obtidos por dois sistemas. Foram avaliados dois diferentes softwares computadorizados, o Wincardio Micromed® (WIN) e o modelo TEB ECGPC® (TEB). Quarenta e dois cães hígidos, de diferentes raças (Cocker Spaniel, Daschund, Labrador, Pinscher, Pit Bull Terrier Poodle, Schnauzer, Shit Tzu, Yorkshire e sem raça definida), machos e fêmeas e com idade entre 4 meses e 16 anos foram agrupados segundo o peso e examinados pelos dois sistemas. As medidas eletrocardiográficas dos diferentes traçados foram analisadas na derivação DII. Os resultados indicaram que o sistema TEB apresentou maior sensibilidade na obtenção das medidas de duração da onda P e do complexo QRS, enquanto o sistema WIN foi mais sensível para determinar as medidas de amplitude dos mesmos parâmetros. Os animais de maior porte (26-37kg) apresentaram maior variância nas medidas de duração e amplitude de onda P e duração do complexo QRS em comparação aos cães de médio (14-25kg) e pequeno (1-13kg) porte. O achado de diferenças entre os sistemas testados deve ser levado em consideração ao se empregar os diversos equipamentos para diagnóstico por meio de ECG-C na rotina clínica, de modo a evitarem-se divergências na interpretação dos exames entre diferentes prestadores de serviços veterinários.

Relación entre la dispersión de la onda P, el índice de masa ventricular izquierda y la tensión arterial / Relationship between P wave dispersion, left ventricular mass index and blood pressure

Introducción. El estudio de los factores de riesgo para padecer hipertensión arterial en los niños garantiza establecer políticas de salud a fin de evitar futuras complicaciones asociadas a esta enfermedad. Los mayores valores de dispersión de la onda P, mientras el paciente está en ritmo sinusal, se señalan como predictores de fibrilación auricular en el adulto, ya que existe una asociación entre la hipertensión arterial, la dispersión de la onda P y la hipertrofia ventricular izquierda. Nuestro objetivo fue determinar la relación entre la tensión arterial, el índice de masa ventricular izquierda y la dispersión de la onda P en pediatría. Población y métodos. Se estudiaron, en el marco del proyecto PROCDEC II, niños de 8 a 11 años, sin cardiopatías conocidas. En todos se midió la tensión arterial y se realizó un electrocardiograma de superficie de 12 derivaciones y un ecocardiograma. Resultados. Los valores de la media del índice de masa ventricular izquierda para normotensos (25,21 ± 5,96 g/m²) e hipertensos (30,38 ± 7,39 g/m²) mostraron diferencias significativas (p= 0,000). La media del área auricular izquierda mostró diferencias significativas (p= 0,000) al comparar los prehipertensos (10,98 ± 2,23 cm²) e hipertensos (12,21 ± 1,27 cm²) con los normotensos (10,66 ± 2,38 cm²). La correlación entre la dispersión de la onda P y el índice de masa ventricular izquierda mostró r= 0,87 y p= 0,000. Conclusiones. La dispersión de la onda P está incrementada en los prehipertensos e hipertensos en relación con los normotensos. Se encontró una dependencia de la dispersión de la onda P del índice de masa ventricular izquierda en los hipertensos.

Introduction. The study of arterial hypertension risk factors in children guarantees the establishment of health policies to avoid complications associated with this illness in the future. The highest values of P-wave dispersion during sinus rhythm are pointed as predictors of atrial fibrillation in adulthood since there is an association between arterial hypertension, P-wave dispersion and left ventricular hypertrophy. The aim of this study was to determine the relationship between blood pressure, left ventricular mass index and P-wave dispersion in the pediatric population. Population and methods. In the frame of the PROCDEC II project, children from 8 to 11 years old, without known heart conditions were studied. Arterial blood pressure was measured in all the children; a 12-lead surface ECG and an echocardiogram were done as well. Results. Left ventricular mass index mean values for normotensive (25.21 ± 5.96 g/m²) and hypertensive (30.38 ± 7.39 g/m²) children showed significant differences (p= 0.000). The mean value of the left atrial area was significantly different (p= 0.000) when comparing prehypertensive (10.98 ± 2.23 cm2) and hypertensive (12.21 ± 1.27 cm²) children to normotensive ones (10.66 ± 2.38 cm²). The correlation of P-wave dispersion and the left ventricular mass index showed an r= 0.87 and p= 0.000. Conclusions. P-wave dispersion is increased in pre- and hypertensive children compared to normotensive ones. A dependence of the P-wave dispersion of the left ventricular mass index was found in hypertensive children.

Dispersão da onda P e índice de volume do átrio esquerdo como preditores na insuficiência cardíaca / P-wave dispersion and left atrial volume index as predictors in heart failure

FUNDAMENTO: Estudos demonstram que a dispersão da onda P (DP) e o índice de volume do átrio esquerdo (Aesc) são preditores de eventos cardiovasculares (EC). OBJETIVO: Verificar o valor prognóstico da dispersão da onda P e do Aesc para a ocorrência de EC em pacientes com insuficiência cardíaca. MÉTODOS: Estudo longitudinal e prospectivo com 78 pacientes consecutivos com idade média de 47,2 anos, sendo 52 homens, estáveis com insuficiência cardíaca, submetidos à avaliação clínica, aos exames de eletrocardiograma e ao ecocardiograma, com seguimento de 26,5 meses. RESULTADOS: As médias das variáveis foram: 50 ms DP e 35,5 ml/m² Aesc. Considerando-se DP > 40 ms e como referência Aesc > 28 ml/m², o valor preditivo positivo da DP foi de 87,5% e o negativo de 76,9%. Durante o seguimento, 21 pacientes apresentaram EC. Houve associação entre as medidas do átrio esquerdo, os volumes do ventrículo esquerdo e a fração de ejeção e EC. Não houve associação entre a DP e EC. Pela análise multivariada, o átrio esquerdo e o Aesc foram preditores de eventos (p = 0,00 e 0,02). Pela curva de operação característica para a variável estável EC, foram obtidas as áreas de 0,80 e 0,69 para Aesc (p = 0,00) e Aesc > 28 ml/m² (p = 0,01). As curvas de sobrevida (Kaplan-Meier) livre daqueles eventos para Aesc > 28 ml/m² e para a etiologia chagásica demonstraram razão de chance de 14,4 (p = 0,00) e de 3,2 (p = 0,03). Não houve diferença de evolução entre pacientes com insuficiência cardíaca isquêmica e não isquêmica. CONCLUSÃO: DP não esteve correlacionada a EC. Aesc foi um preditor independente de EC e os chagásicos apresentaram pior evolução.

BACKGROUND: Studies have shown that P-wave dispersion (PWD) and left atrial volume index (LAVi) are predictors of cardiovascular events (CE). OBJECTIVE: To verify the prognostic value of PWD and LAVi for the occurrence of CE in patients with heart failure (HF). METHODS: This was a longitudinal prospective study of 78 consecutive patients with a mean age of 47.2 years, of which 52 were males. Patients had stable HF and underwent clinical evaluation, electrocardiogram and echocardiogram assessments, with a follow-up of 26.5 months. RESULTS: The means of the variables were: 50 ms for PWD and 35.5 mL/m² for LAVi. Considering PWD > 40 ms and, as reference, LAVi > 28 mL/m², the positive predictive value of PWD was 87.5% and the negative predictive value was 76.9%. During follow-up, 21 patients had CE. There was an association between left atrial measurements, left ventricular volumes, ejection fraction and CE. There was no association between PWD and CE. At the multivariate analysis, the left atrium and LAVi were predictors of events (p = 0.00 and 0.02). Through the operating characteristic curve for the variable stable CE, areas of 0.80 and 0.69 were obtained for LAVi (p = 0.00) and LAVi > 28 mL/m² (p = 0.01). Survival curves (Kaplan-Meier) free of those events for LAVi > 28 mL/m² and for Chagas disease etiology showed an odds ratio of 14.4 (p = 0.00) and 3.2 (p = 0.03). There was no difference in outcome between patients with ischemic and nonischemic heart failure. CONCLUSION: PWD was not correlated to CE. LAVi was an independent predictor of CE, and chagasic patients showed worse outcomes.

Incremento en la dispersión de la onda P al disminuir el tiempo de eyección auricular en hipertensos y prehipertensos / Increment in P wave dispersion by decreasing atrial ejection time in hypertensive and prehypertensive patients

Introducción: hace algunos años se viene estudiando la relación entre disfunción diastólica y dispersión de la onda P del electrocardiograma, y en este sentido, la ecocardiografía emerge como herramienta para mejorar la estratificación de riesgo en hipertensos leves. Objetivo: determinar la dependencia de la dispersión de la onda P del electrocardiograma de variables ecocardiográficas en una población pediátrica. Métodos: se estudiaron 400 niños, de un total de 450, pertenecientes a tres escuelas primarias, y se excluyeron aquellos cuyos padres no desearon que participaran en el estudio y a quienes tuvieran patologías congénitas conocidas. Se realizó electrocardiograma de superficie de doce derivaciones y se practicaron cuatro tomas de presión arterial. Se midieron los valores de P máxima y P mínima, y se calculó la dispersión de la onda P del electrocardiograma; además se hizo, ecocardiografía para mediciones estructurales y Doppler pulsado del flujo mitral. Resultados: los valores de media para la duración de la onda A del flujo mitral no muestran diferencias significativas; sin embargo, existe un coeficiente de correlación (r) y p significativos entre la dispersión de la onda P y la duración de la onda A del flujo mitral para normotensos (r= - 0,117 p=0,05), prehipertensos (r= - 0,309 p=0,001) e hipertensos (r= - 0,586 p=0,001). Existen diferencias significativas entre las medias de dispersión de la onda P entre los grupos de diagnóstico. Conclusiones: se evidencia dependencia de la dispersión de la onda P, del electrocardiograma y de la duración de la onda A del flujo de entrada mitral, hechos que se relacionan con riesgo de fibrilación auricular en el adulto, por lo que quizás este resultado dé un acercamiento a predicciones de riesgo más tempranas en edades pediátricas.

Introduction: the relationship between diastolic dysfunction and P wave dispersion in the electrocardiogram is being studied since some years ago, and in this regard echocardiography is emerging as a tool to improve risk stratification in mild hypertension. Objective: to determine the dependence of the dispersion of the P wave of electrocardiogram with echocardiographic variables in a pediatric population. Methods: we studied 400 children from a total of 450 belonging to three elementary schools, and excluded those whose parents did not want them to participate in the study and those who had known congenital diseases. We performed 12-lead surface ECG and 4 blood pressure takings. We measured maximum and minimum P values and calculated P wave dispersion in the electrocardiogram. Echocardiography for structural measurements and pulsed Doppler of mitral flow were also performed. Results: mean values for duration of A wave of mitral flow showed no significant differences; however, there is a correlation coefficient (r) and significant p between P wave dispersion and duration of mitral flow A wave for normotensive (r = - 0.117 p = 0.05), NT (r = - 0.309 p = 0.001) and hypertensive (r = - 0.586 p = 0.001). There are significant differences between the mean P wave dispersion between diagnostic groups. Conclusions: we highlight the dependence of P wave dispersion, the electrocardiogram and the duration of the mitral inflow A wave, events that are related to risk of atrial fibrillation in adults, so perhaps this result gives an approach to earlier risk predictions in pediatric patients.

Del impulso eléctrico auricular heterogéneo a la fibrilación auricular: ¿cómo preverla en el electrocardiograma? / Hererogeneous atrial electrical impulse to atrial fibrillation: how to anticipate on electrocardiogram?

El impulso sinusal se origina en el nodo y su propagación depende de la complejidad anatómica de los atrios. Las superficies septales interauriculares derechas e izquierdas, muestran un patrón discordante de activación. Modelos de laboratorios con músculo auricular humano, han llegado a producir el remodelado eléctrico que se encuentra en pacientes que padecen de fibrilación auricular. En el remodelado estructural se describe la dilatación auricular y la fibrosis intersticial de las aurículas, en estos mecanismos se le ha dado gran implicación al sistema renina angiotensina aldosterona. En la fisiopatología de la FA se describen los siguientes factores: factor genético: está implicado en los casos de FA familiar; factor predisponente estructural: dilatación auricular, el factor estructural más conocido que permite el desarrollo de la FA; factor predisponente estructural: el haz de Bachmann y las vías de conducción interauricular establecen gradientes de frecuencia entre la aurícula izquierda y la derecha, lo que les confiere un papel en la conducción fibrilatoria; factores predisponentes electrofisiológicos: períodos refractarios heterogéneos favorecen la generación de fibrilación auricular; factores desencadenantes: papel de la actividad eléctrica anormal (“focos ectópicos”); y factores moduladores: papel del sistema nervioso autónomo. Para prever la fibrilación auricular es un excelente método calcular la dispersión de la onda P del electrocardiograma.

The sinus impulse originates in the node and its propagation depends on the anatomical complexity of the atria. Atrial septal surfaces left and right, show a discordant pattern of activation. Laboratory model of human atrial muscle have come to produce electrical remodeling found in patients suffering from atrial fibrillation. In the described structural remodeling and atrial dilation, interstitial fibrosis of the atria in these mechanisms has been given much involvement the renin angiotensin aldosterone. In the pathophysiology of FA described the following factors: Genetic factors are involved in cases of familial AF, structural predisposing factor: atrial dilatation, the best knownstructural factor that allows the development of AF, structural predisposing factor: the beam Bachmann and interatrial pathway down frequency gradients between the left atrium and right, givind them a role in fibrillatory, electrophysiologic predisposing factors: heterogeneous refractory periods favour the generation of Atrial Fibrillation triggers: the role abnormal electrical activity (ectopic foci), and modulating factors: role of autonomic nervous system. To provide for atrial fibrillation is an excellent method to calculate thedispersion of the P wave of electrocardiogram.

Dispersión de la onda P en el electrocardiograma con bases en el potencial de acción auricular y en la heterogerneidad del impulso en aurículas / Wave dispersion in the electrocardiogram based on the atrial action potential and the heterogeneity of the impulse in the atrial muscle

Resumem: La fibrilación auricular es la forma más común de alteración del ritmo cardiaco, que afecta alrededor de 2,3 millones de personas en Norteamérica y a 4,5 millones de la Unión Europea. Muchos estudios han mostrado la presencia de hipertensión arterial em pacientes que desarrollan fibrilación auricular y esta interrelación potencia sus deletéreos. Las superficies septales interauriculares derechas e izquierdas muestram un patrón discordante de activación. La activación septal izquierda comienza 10 msec más tarde que la porción superior de la septal derecha y se han observado diferencias de hasta 40 msec em ritmos como la fibrilación auricular. El potencial de membrana en reposo del músculo cardiaco es de aproximadamente -80 Mv y su equilibrio está determinado fundamentalmente por el ion potasio (K+). Las bases iónicas del remodelado eléctrico auricular...

Icremento en la dispersión de la onda P dependiente de la tensión arterial media en prehipertensos e hipertensos / Increased P wave dispersion dependent on mean arterial pressure in prehypertensive and hypertension / Aumento da dispersão da onda P dependente da tensão arterial média em préhipertensos e hipertensos

Introducción: La dispersión de onda P del electrocardiograma, constituye una herramienta para predecir fibrilación auricular. Los mayores valores de dispersión de onda P se han relacionado en adultos con parixismo de Fibrilación Auricular. Material y métodos: En tres escuelas primarias, del total de 450 alumnos entre 8 a 11 años de edad, se estudiaron 400 niños, excluyendo aquellos que sus padres no desearon que participaran en el estudio y aquellos con patologías congénitas conocidas. Se les realizó electrocardiograma, y se practicaron cuatro tomas de presión arterial. Se midieron los valores de P máxima, P mínima en cada una de las 12 derivaciones y se calculó la dispersión de la onda P. Resultados: La media de dispersión de la onda P es mayor en hipertensos que en normotensos...

Introduction: P wave dispersion in the electrocardiogram, is a tool for predicting atrial fibrillation. The highest values of P wave dispersion have been associated in adults with paroxysmof atrial fibrillation. Material and methods: In three primary schools, the total of 450 students between 8-11 years of age, 400 children were studied, excluding those whose parents did not want to participate in the study and those with known congenital diseases. Electrocardiogram was performed, and four blood pressure taps were performed. We measured the values of P maximum, P minimum in each ofthe 12 leads was calculated and the P wave dispersion. Results: The mean P wave dispersion is higher in hypertensive than in normotensive (38.5 to 32.5, respectively, p=0.04). There was significant correlation between P wave dispersion and mean arterial pressure for prehypertensive and hypertensive r=0.334, p=0.000 and r=0.37, p=0.000, respectively. Discussion: The increase in the values of P wave dispersion is associated with increases in vulnerability to developing atrial arrhythmias. Conclusions: There are significant differences between the values of P wave dispersion of the electrocardiogram in normotensive populations, prehypertensive and hypertensive since childhood.

Introdução: A dispersão de onda P do eletrocardiograma constitui uma ferramenta para predizer fibrilação atrial. Os maiores valores de dispersão de onda P têm sido relacionados emadultos com paroxismo de Fibrilação Atrial. Material e métodos: Em três escolas primárias, do total de 450 alunos entre 8 e 11 anos de idade, foram estudadas 400 crianças, excluindo aquelas cujos pais não desejaram que participassem do estudo e aquelas com patologias congênitas conhecidas. Foi realizado eletrocardiograma nelas e também foi tirada sua pressão arterial quatro vezes. Foram medidos os valores de P máxima, P mínima em cada uma das 12 derivações e foi calculada a dispersão da onda P. Resultados: A média de dispersão da onda P é maior em hipertensos que em normotensos (38.5 a 32.5; respectivamente, p=0.04). Existe correlação significativa entre dispersão da onda P e a tensão arterial média para pré-hipertensos e hipertensos: r=0.334, p=0.000 e r=0.37,p=0.000; respectivamente. Discussão: O aumento nos valores de dispersão de onda P está relacionado com aumentos na vulnerabilidade atrial para o desenvolvimento de arritmias. Conclusões: Existem diferenças significativas entre os valores de dispersão de onda P do eletrocardiograma em populaçõesnormotensas, pré-hipertensas e hipertensas desde a infância.

Marcadores eletrocardiográficos para detecção precoce de doença cardíaca em pacientes com talassemia beta maior / Electrocardiographic markers for the early detection of cardiac disease in patients with beta-thalassemia major

OBJETIVO: Analisar comparativamente a dispersão da onda P (DOP) em pacientes com talassemia beta maior (β-TM) e indivíduos saudáveis (controles) para a detecção precoce do risco de arritmias. MÉTODOS: Oitenta e uma crianças com β-TM, com idades entre 4 e 19 anos, e 74 crianças saudáveis (grupo controle) foram submetidas a exame eletrocardiográfico e ecocardiograma transtorácico de rotina para avaliação cardíaca. A DOP foi calculada como a diferença entre as durações máxima e mínima da onda P. RESULTADOS: Houve uma diferença estatisticamente significativa entre o grupo de estudo e o grupo controle no pico de velocidade do fluxo transmitral no início da diástole (E) e na razão E/fluxo transmitral tardio (A). A duração máxima da onda P e a DOP foram significativamente maiores nos pacientes com β-TM do que nos indivíduos controles. CONCLUSÕES: O aumento da DOP em nossos pacientes com β-TM pode estar relacionado à depressão na condução intra-atrial, devido à dilatação atrial, e ao aumento da atividade simpática. Estes pacientes devem ser acompanhados atentamente devido à possibilidade de ocorrência de arritmias com risco de vida.

OBJECTIVE: To comparatively evaluate P-wave dispersion (PWD) in patients with β-thalassemia major (TM) and healthy control subjects for the early prediction of arrhythmia risk. METHODS: Eighty-one children with β-TM, aged 4-19 years, and 74 healthy children (control group) underwent routine electrocardiography and transthoracic echocardiography for cardiac evaluation. PWD was calculated as the difference between the maximum and the minimum P-wave duration. RESULTS: There was a statistically significant difference between study and control groups in peak early (E) mitral inflow velocity and E/late (A) velocity ratio. Maximum P-wave duration and PWD were found to be significantly higher in β-TM patients than in control subjects. CONCLUSIONS: Increased PWD in our β-TM patients might be related to depression of intra-atrial conduction due to atrial dilatation and increased sympathetic activity. These patients should be closely followed up for risk of life-threatening arrhythmias.