Unusual ventricular activation produced by temporary transvenous cardiac pacing: electrovectorcardiographic findings / Activación ventricular inusual producida por estimulación cardíaca transvenosa temporal: hallazgos electrovectorcardiográficos

Abstract Complete heart block (CHB) results from dysfunction of the cardiac conduction system, which results in complete electrical dissociation. The ventricular escape rhythm can have its origin anywhere from the atrioventricular node to the bundle branch-Purkinje system. CHB typically results in bradycardia, hypotension, fatigue, hemodynamic instability, syncope, or even Stokes-Adams syndrome. Escape rhythm originating above the bifurcation of the His bundle (HB) produces narrow QRSs with relatively rapid heart rate (HR) (except in cases of His system disease). We present a middle-aged man with an HR of 34 bpm, progressive fatigue, in whom a temporary pacemaker was implanted in the subtricuspid region. The post-intervention electrocardiogram had unusual features.

Resumen El bloqueo cardíaco completo (BCC) resulta de la disfunción del sistema de conducción cardíaco, lo que ocasiona una disociación eléctrica completa entre aurículas y ventrículos. El ritmo de escape resultante puede tener su origen en cualquier lugar desde el nodo auriculoventricular hasta el sistema His Purkinje. El BCC generalmente produce bradicardia, hipotensión, fatiga, inestabilidad hemodinámica, síncope o incluso el síndrome de Stokes-Adams. El ritmo de escape que se origina por encima de la bifurcación del haz de His produce intervalos QRS estrechos con frecuencia cardíaca no muy lenta (excepto en casos de enfermedad del sistema Hisiano). Presentamos a un hombre de mediana edad con una frecuencia cardíaca de 34 lpm, fatiga progresiva, en el que se implantó un marcapasos temporario en la región subtricuspídea. El electrocardiograma resultante a la intervención presentó características inusuales.

Bloqueo de rama alternante en una taquicardia supraventricular: ¿Cuál es el mecanismo subyacente? / Alternating bundle branch block in a supraventricular tachycardia: Which is the mechanism ?

El bloqueo de rama funcional durante una taquicardia supraventricular puede ser observado con longitudes de ciclo cortas y representa una respuesta fisiológica del sistema de conducción intraventricular por la existencia de conducción nodal auriculo ventricular acelerada. Presentamos el caso de un paciente joven con taquicardia reentrante aurículo-ventricular ortodrómica y bloqueo de rama alternante. Esta respuesta infrecuente se explica por el hallazgo obtenido durante el estudio electrofisiológico. Una conducción nodal aurículo-ventricular acelerada produce un frente de onda que despolariza las ramas durante sus períodos refractarios. Una vez que ocurrió el bloqueo en una de las ramas, dicho bloqueo persistió debido al fenómeno de linking, que es por conducción oculta retrógrada repetitiva de la rama contralateral. Después de la ablación transcatéter de una vía accesoria oculta lateral izquierda, el marcapaseo auricular rápido a la misma longitud de ciclo de la taquicardia, reprodujo la misma aberrancia observada durante la taquicardia. Este procedimiento demostró que el bloqueo de rama funcional fue debido a la longitud de ciclo corto y no a la presencia de una vía accesoria aurículo-ventricular.

Functional bundle branch block during a supraventricular tachycardia can be observed with shorter cycle lengths and represent a physiologic response by the specialized intraventricular conduction system to accelerated AV nodal conduction. The present case corresponds to a young patient with exercise induced orthodromic A-V reentrant tachycardia and alternating bundle branch block. This unusual response is explained by the finding obtained during the electrophysiology study. An accelerated AV nodal conduction made the depolarizing wave front reach the bundle branches during their refractory period. Once block in one bundle was stablished, block persisted due to the linking phenomenon that is repetitive retrograde concealed conduction from the contralateral bundle. After catheter ablation of a concealed left-sided accessory A-V pathway, rapid atrial pacing at the same cycle length of the tachycardia reproduced the same aberrancies observed during tachycardia. This response proved that functional bundle branch block is due to the short cycle length and not the presence of an accessory A-V pathway.

Longitudinal follow-up of cardiac vagal activity in individuals undergoing endoscopic thoracic sympathectomy / Acompanhamento longitudinal da atividade vagal cardíaca de indivíduos submetidos à simpatectomia torácica endoscópica

ABSTRACT Objective: To conduct a longitudinal investigation of cardiac vagal activity (CVA) by measuring resting HR and calculating the cardiac vagal index (CVI) in individuals undergoing sympathectomy for the treatment of primary hyperhidrosis. Methods: This was a descriptive longitudinal study involving 22 patients, 13 of whom were female. The mean age was 22.5 ± 8.8 years. The palms, soles, and axillae were the most commonly affected sites. Resting HR was measured by an electrocardiogram performed 20 min before the 4-second exercise test (4sET), which was used in order to evaluate CVA at three different time points: before surgery, one month after surgery, and four years after surgery. Results: Resting HR (expressed as mean ± SE) was found to have decreased significantly at 1 month after surgery (73.1 ± 1.6 bpm before surgery vs. 69.7 ± 1.2 bpm at one month after surgery; p = 0.01). However, the HR values obtained at four years after surgery tended to be similar to those obtained before surgery (p = 0.31). The CVI (expressed as mean ± SE) was found to have increased significantly at one month after surgery (1.44 ± 0.04 before surgery vs. 1.53 ± 0.03 at one month after surgery; p = 0.02). However, the CVI obtained at four years after surgery tended to be similar to that obtained before surgery (p = 0.10). Conclusions: At one month after sympathectomy for primary hyperhidrosis, patients present with changes in resting HR and CVA, both of which tend to return to baseline at four years after surgery.

RESUMO Objetivo: Investigar longitudinalmente o comportamento da atividade vagal cardíaca (AVC) por meio da FC de repouso e do índice vagal cardíaco (IVC) de indivíduos submetidos à simpatectomia para o tratamento de hiperidrose primária. Métodos: Estudo de natureza descritiva e longitudinal que avaliou 22 pacientes (13 mulheres), com média de idade de 22,5 ± 8,8 anos. Os locais mais afetados eram as mãos, pés e axilas. A FC de repouso média foi mensurada através de eletrocardiograma 20 min antes do teste de exercício de 4 segundos (T4s), que foi utilizado para a avaliação da AVC em três momentos: antes da cirurgia, um mês após a cirurgia e quatro anos após a cirurgia. Resultados: A média ± erro-padrão da FC de repouso apresentou uma redução significativa entre a avaliação pré-operatória e um mês após a cirurgia (73,1 ± 1,6 bpm vs. 69,7 ± 1,2 bpm; p = 0,01), tendendo a retornar aos valores pré-operatórios quatro anos após a cirurgia (p = 0,31). Houve um aumento significativo do IVC entre o pré-operatório e um mês após a cirurgia (1,44 ± 0,04 vs. 1,53 ± 0,03; p = 0,02), tendendo também a retornar próximo aos valores do pré-operatório após quatro anos da cirurgia (p = 0,10). Conclusões: A simpatectomia resultou em alteração na FC de repouso e na AVC um mês após a cirurgia, retornando, após quatro anos, aos valores próximos do pré-operatório.

Reproducibility and Reliability Of QTc and QTcd Measurements and Their Relationships with Left Ventricular Hypertrophy in Hemodialysis Patients / Reprodutibilidade e Confiabilidade das Medidas de QTc e DQTc e suas Relações com a Hipertrofia Ventricular Esquerda em Pacientes em Hemodiálise

Abstract Background: Left ventricular hypertrophy (LVH) is very common in hemodialysis patients and an independent risk factor for mortality in this population. The myocardial remodeling underlying the LVH can affect ventricular repolarization causing abnormalities in QT interval. Objective: to evaluate the reproducibility and reliability of measurements of corrected QT interval (QTc) and its dispersion (QTcd) and correlate these parameters with LVH in hemodialysis patients. Methods: Case-control study involving hemodialysis patients and a control group. Clinical examination, blood sampling, transthoracic echocardiogram, and electrocardiogram were performed. Intra- and interobserver correlation and concordance tests were performed by Pearson´s correlation, Cohen's Kappa coefficient and Bland Altman diagram. Linear regression was used to analyze association of QTc or QTcd with HVE. Results: Forty-one HD patients and 37 controls concluded the study. Hemodialysis patients tended to have higher values of QTc, QTcd and left ventricular mass index (LVMi) than controls but statistical significance was not found. Correlation and concordance tests depicted better results for QTc than for QTcd. In HD patients, a poor but significant correlation was found between QTc and LVMi (R2 = 0.12; p = 0.03). No correlation was found between values of QTcd and LVMi (R2= 0.00; p=0.940). For the control group, the correspondent values were R2= 0.00; p = 0.67 and R2= 0.00; p = 0.94, respectively. Conclusion: We found that QTc interval, in contrast to QTcd, is a reproducible and reliable measure and had a weak but positive correlation with LVMi in HD patients.

Resumo Fundamentos: A hipertrofia ventricular esquerda (HVE) é muito comum em pacientes em hemodiálise e um fator de risco independente de mortalidade nessa população. O remodelamento do miocárdio, subjacente à HVE, pode afetar a repolarização ventricular, causando anormalidades no intervalo QT. Objetivo: avaliar a reprodutibilidade e confiabilidade das medidas do intervalo QT corrigido (QTc) e sua dispersão (QTcd), e correlacionar esses parâmetros com HVE em pacientes em hemodiálise. Métodos: Estudo caso-controle envolvendo pacientes em hemodiálise e um grupo controle. Foram realizados avaliação clínica, coleta de sangue, ecocardiografia transtorácica, e eletrocardiograma. Testes de correlação e concordância intraobservador e interobservador foram realizados por correlação de Pearson, coeficiente kappa de Cohen e diagrama de Bland Altman. A regressão linear foi usada para analisar a associação entre QTc ou QTcd e HE. Resultados: Quarenta e um pacientes em hemodiálise e 37 controles completaram o estudo. Houve uma tendência de os pacientes apresentarem valores mais altos de QTc, QTcd e de índice de massa ventricular esquerda que os controles, mas sem significância estatística. Os testes de correlação e de concordância apresentaram melhores resultados para QTc que para QTcd. Em pacientes em hemodiálise, uma correlação fraca, mas significativa foi encontrada entre QTc e IMVE (R2 = 0,12; p = 0,03). Não foi encontrada correlação entre QTcd e IMVE (R2 = 0,00; p=0,940). Para o grupo controle, esses valores correspondentes foram R2 = 0,00; p = 0,67 e R2 = 0,00; p = 0,94, respectivamente. Conclusão: o intervalo QTc, diferentemente do intervalo QTcd, é uma medida reprodutível e confiável, e apresentou uma correlação fraca, mas positiva com o IMVE em pacientes em hemodiálise.

Electrical approach to improve left ventricular activation during right ventricle stimulation

Coronary sinus mapping is commonly used to evaluate left atrial activation. Herein, we propose to use it to assess which right ventricular pacing modality produces the shortest left ventricular activation times (R-LVtime) and the narrowest QRS widths. Three study groups were defined: 54 controls without intraventricular conduction disturbances; 15 patients with left bundle branch block, and other 15 with right bundle branch block. Left ventricular activation times and QRS widths were evaluated among groups under sinus rhythm, right ventricular apex, right ventricular outflow tract and high output septal zone (SEPHO). Left ventricular activation time was measured as the time elapsed from the surface QRS onset to the most distal left ventricular deflection recorded at coronary sinus. During the above stimulation modalities, coronary sinus mapping reproduced electrical differences that followed mechanical differences measured by tissue doppler imaging. Surprisingly, 33% of the patients with left bundle branch block displayed an early left ventricular activation time, suggesting that these patients would not benefit from resynchronization therapy. SEPHO improved QRS widths and left ventricular activation times in all groups, especially in patients with left bundle branch block, in whom these variables became similar to controls. Left ventricular activation time could be useful to search the optimum pacing site and would also enable detection of non-responders to cardiac resynchronization therapy. Finally, SEPHO resulted the best pacing modality, because it narrowed QRS-complexes and shortened left ventricular activations of patients with left bundle branch block and preserved the physiological depolarization of controls.

El mapeo del seno coronario se utiliza comúnmente para evaluar la activación de la aurícula izquierda. Aquí, investigamos su utilidad para evaluar qué modalidad de estimulación ventricular derecha produce los menores tiempos de activación ventricular izquierda (R-LVtime). Se definieron tres grupos: 54 controles; 15 pacientes con bloqueo de rama izquierda y 15 con bloqueo de rama derecha. El ancho de QRS y los tiempos de activación fueron evaluados en cada grupo bajo las siguientes modalidades: ritmo sinusal, ápex del ventrículo derecho, tracto de salida del ventrículo derecho y alta salida en septum (SEPHO). El R-LVtime se midió como el tiempo transcurrido desde el inicio del QRS de superficie y la deflexión ventricular izquierda más distal del seno coronario. Durante las distintas modalidades de estimulación, el mapeo del seno coronario reprodujo diferencias eléctricas acompañadas por diferencias mecánicas que fueron evaluadas mediante Tissue Doppler Imaging. El 33% de los pacientes con bloqueo de rama izquierda mostró R-LVtime tempranos, lo que sugiere que estos pacientes no se beneficiarían con terapia de resincronización. SEPHO mejoró el ancho de QRS y el R-LVtime de todos los grupos, especialmente en los pacientes con bloqueo de rama izquierda. En conclusión, el R-LVtime serviría para identificar el sitio óptimo de estimulación y permitiría detectar ciertos no respondedores a la terapia de resincronización. Además, el SEPHO resultó la mejor modalidad de estimulación porque estrechó el QRS y acortó el R-LVtime de los pacientes con bloqueo de rama izquierda pero no alteró la despolarización fisiológica de los controles.

Impact of Myocardial Infarction and Abnormalities of Cardiac Conduction System on Sudden Cardiac Death / 法医学杂志

Sudden cardiac death （SCD）, most commonly seen in coronary heart disease, is a kind of sudden death caused by series of cardiac parameters, which usually combines with myocardial infarction. However, some SCDs （including early myocardial infarction） happen suddenly and cause death in a very short time. In these circumstances, typical morphological changes are lack in macroscopic or microscopic fields, which make such SCDs become the emphasis and difficulty in the present research. SCD caused by myocardial infarction and abnormalities of cardiac conduction system （CCS） is related to atherosclerosis of coronary artery closely. This paper reviews cardiac dysfunction caused by myocardial infarction and diseases of CCS from morphology and molecular biology, and explores potential relationship between them. This paper aims to provide clues to the mechanism of myocardial infarction related sudden death and possible assistance for forensic diagnosis of SCD.

Bloqueo interauricular como sustrato anatómico-eléctrico de arritmias supraventriculares: síndrome de Bayés / Interatrial block as anatomical-electrical substrate for supraventricular arrhythmias: Bayes' syndrome

En este artículo hemos querido establecer que el bloqueo interauricular existe como entidad anatomoeléctrica y que debe ser considerado como un verdadero bloqueo. El bloqueo interauricular presenta diferentes grados al igual que otros bloqueos del sistema de conducción. Puede presentarse como expresión de remodelado puramente eléctrico o acompañar alteraciones estructurales que dilaten las aurículas. Se encuentra asociado a arritmias supraventriculares y es probablemente un predictor de accidente cerebrovascular cardioembólico. El bloqueo interauricular puede presentarse de manera transitoria, y en ciertas circunstancias clínicas, puede ser reversible. El aporte del mapeo endocavitario ha incrementado el conocimiento sobre su anatomía y fisiopatología, y posiblemente la magnetocardiografía podría contribuir al estudio no invasivo de esta entidad. La terminología a utilizar debería ser bloqueo interauricular de primer, segundo y tercer grado o alternativamente, y en función de simplificar: parcial o avanzado. La morfología de la onda P, en función de diagnosticar el grado avanzado, siempre debería ser tenida en cuenta. Para finalizar, debemos reconocer el aporte fundamental que el Dr. Bayés de Luna ha establecido sobre la relación del bloqueo interauricular con las arritmias supraventriculares conformando un síndrome arrítmico indiscutido; lo cual a nuestro criterio representa un aporte mayor al conocimiento de la electrocardiografía y la electrofisiología, y hace meritorio que este síndrome arrítmico sea denominado <

In this article we aimed to establish that interatrial block exists as an anatomical-electrical entity, which should be considered a true block. Interatrial block presents with different degrees as other blocks in the conduction system. It shows a correlation with the left atrium size, however, it can be seen in patients with normal atrial size too. Interatrial block is strongly associated with atrial arrhythmias and it could be considered a predictor of cardioembolic stroke. Interatrial block is an expression of atrial electrical remodeling and dysfunction. IAB can be transient and in certain clinical circumstances, may be reversible. The contribution of endocardial mapping has increased our knowledge of the anatomy and pathophysiology of interatrial block. Magnetocardiography could be a possible non-invasive procedure to further investigate this entity. The interatrial block classification should include first, second and third degree or alternatively, in order to simplify the terminology: partial or advanced. The P wave morphology should always be taking into consideration when diagnosing this condition. Finally, without the initial description of interatrial block made by Dr. Bayés de Luna, it would be impossible to understand interatrial block as an anatomical and electrical substrate for atrial arrhythmias. It is our opinion that this represents a major contribution to the knowledge of electrocardiography and electrophysiology, and makes commendable that this arrhythmic syndrome should be called <

Malignant arrhythmia as the first manifestation of Wolff-Parkinson-White syndrome: a case with minimal preexcitation on electrocardiography / Arritmia maligna como primera manifestación del síndrome de Wolff-Parkinson-White: un caso con preexcitación mínima en la electrocardiografía

Wolff-Parkinson-White (WPW) syndrome is defined as the presence of an accessory atrioventricular pathway which is manifested as delta waves and short PR interval on electrocardiography (ECG). However, some WPW cases do not have typical findings on ECG and may remain undiagnosed unless palpitations occur. Sudden cardiac death may be the first manifestation of WPW and develops mostly secondary to degeneration of atrial fibrillation into ventricular fibrillation. In this report, we present a case of undiagnosed WPW with minimal preexcitation on ECG and who suffered an episode of malignant arrhythmia as the first manifestation of the disease.

El síndrome Wolff-Parkinson-White (WPW) se define como la presencia de una vía accesoria atrioventricular que se manifiesta como ondas delta, e intervalos cortos de PR en el electrocardiograma (ECG). Sin embargo, algunos casos de WPW no tienen resultados típicos en el ECG, y pueden permanecer sin diagnosticar a menos que se produzcan palpitaciones. La muerte cardíaca súbita puede ser la primera manifestación de WPW, y se produce principalmente de forma secundaria a la degeneración de la fibrilación auricular en fibrilación ventricular. En este reporte, presentamos un caso no diagnosticado de WPW con preexcitación mínima en el ECG, con un episodio de arritmia maligna como primera manifestación de la enfermedad.

Estudo da sístole elétrica ventricular nos insuficientes renais crônicos hemodialisados / Study of ventricular electrical systole in patients with end-stage kidney disease on hemodialysis

FUNDAMENTO: Os indivíduos com insuficiência renal crônica terminal estão sujeitos a um elevado estresse cardíaco pelo carácter repetitivo e intermitente da terapia dialítica. As alterações na sístole elétrica ventricular induzidas pela necessária terapia dialítica são um contributo importante na predição da ocorrência de morte súbita arrítmica na insuficiência renal crônica terminal. OBJETIVO: O objetivo principal desta investigação é avaliar o comportamento da repolarização ventricular em face da terapia dialítica, mediante o estudo do intervalo QTc e dispersão do QTc. MÉTODOS: A amostra em estudo inclui 47 indivíduos sujeitos a hemodiálise (61,7% do sexo masculino e 38,3% do sexo feminino) com idade média de 66,79 ± 13,16 anos. Todos os indivíduos foram sujeitos a três eletrocardiogramas realizados em três momentos durante a terapia dialítica (pré, durante e após a sessão), sendo posteriormente analisada a sístole elétrica ventricular. RESULTADOS: Ocorreu um aumento do intervalo QTc máximo e da dispersão do QTc associado à terapia dialítica. Aliado ao aumento desses intervalos ocorreu um aumento do número de indivíduos com critérios eletrocardiográficos para hipertrofia ventricular esquerda, registando-se no período pós-diálise uma média superior do intervalo QTc máximo (473 ± 27,63 mseg) e da dispersão do QTc (58,95 ± 18,87 mseg) desses indivíduos, comparativamente aos indivíduos sem HVE, 455,21 ± 26,85 mseg e 44 ± 16,41 mseg, respectivamente. CONCLUSÃO: O presente estudo confirmou um aumento do intervalo QTc e da dispersão do QTc associado à terapia dialítica. Esse aspecto reforça a dependência da repolarização ventricular em relação ao equilíbrio hídrico e eletrolítico e sugere um perfil de maior vulnerabilidade arrítmica associada à terapia dialítica.

BACKGROUND: Patients with end-stage kidney disease (ESKD) experience elevated cardiac stress because of the repetitive and intermittent character of dialysis. Changes in ventricular electrical systole induced by necessary dialysis significantly contribute to predict sudden death due to arrhythmia in ESKD. OBJECTIVE: The major objective of this study was to assess the behavior of ventricular repolarization in dialysis by analyzing QTc interval and QTc dispersion. METHODS: This study sample consisted of 47 patients undergoing hemodialysis (61.7% males and 38.3% females), whose mean age was 66.79±13.16 years. All of them underwent three electrocardiograms performed before, during and after one dialysis session. Ventricular electrical systole was analyzed later. RESULTS: An increase in maximum QTc interval and QTc dispersion associated with dialysis was observed. In addition, an increase in the number of individuals meeting the electrocardiographic criteria for left ventricular hypertrophy (LVH) was observed. After dialysis, higher means of the maximum QTc interval (473 ± 27.63 mseg) and of the QTc dispersion (58.95 ± 18.87 mseg) were observed in individuals with LVH as compared with those in individuals without LVH (455.21 ± 26.85 mseg and 44 ± 16.41 mseg, respectively). CONCLUSION: This study confirmed an increase in the QTc interval and QTc dispersion associated with dialysis. That emphasizes the dependence of ventricular repolarization on fluid and electrolyte balance, and suggests a profile of higher vulnerability to arrhythmia associated with dialysis .

Estudo transversal das estratégias de tratamento clínico na fibrilação atrial / Cross-sectional study of treatment strategies on atrial fibrillation / Estudio transversal de las estrategias de tratamiento clínico en la fibrilación atrial

FUNDAMENTO: A despeito de elevada prevalência e importância clínica da Fibrilação Atrial (FA), não existem até o momento publicações brasileiras informando o perfil clínico e a estratégia de tratamento (controle de ritmo vs. controle de frequência cardíaca) mais utilizada nesse universo de pacientes. OBJETIVO: Avaliar a estratégia de tratamento mais empregada na FA em ambulatório especializado no manejo dessa doença. Secundariamente, procurou-se descrever o perfil clínico dessa população. MÉTODOS: Estudo transversal que avaliou sequencialmente, em 167 portadores de FA, a estratégia de tratamento mais empregada, bem como o perfil clínico desses pacientes. Utilizou-se questionário padronizado para coleta de dados. A análise estatística foi realizada por meio do software SPSS® versão 13.0. RESULTADOS: Nessa população de alto risco para eventos tromboembólicos (61% com score CHADS2 > 2), em que 54% dos indivíduos apresentavam fibrilação atrial paroxística ou persistente, 96,6% utilizavam antagonistas da vitamina K ou AAS, e 76,6% faziam uso de betabloqueador (81,2% frequência x 58,8% ritmo, p < 0,05); a estratégia de controle de frequência foi a mais empregada (79,5% x 20,5%, p < 0,001). Houve uma tendência estatística a maior agrupamento de pacientes com disfunção ventricular (15,2% x 2,9%; p = 0,06), CHADS2 > 2 (60,5% x 39,5%; p = 0,07) e valvopatias (25,8% x 11,8%; p = 0,08) no segmento de controle da frequência. CONCLUSÃO: Nessa população de alto risco para eventos tromboembólicos, a estratégia de controle de frequência cardíaca foi a mais empregada.

BACKGROUND: Despite the high prevalence and clinical importance of atrial fibrillation (AF), there is no Brazilian study about the clinical profile of patients with AF and the most used treatment strategy (heart rhythm control vs. heart rate control) for them. OBJECTIVE: To assess the most used treatment strategy for AF in an outpatient clinic specialized in the management of that disease. In addition, the clinical profile of the population studied was provided. METHODS: Cross-sectional study assessing sequentially, in 167 patients with AF, the most used treatment strategy, as well as their clinical profile. A standardized form was used for data collection. The statistical analysis was performed by using the SPSS® software, version 13.0. RESULTS: In that population at high risk for thromboembolic events (61% had CHADS2 > 2), 54% of the patients had paroxysmal or persistent AF, 96.6% used vitamin K antagonists or acetylsalicylic acid, and 76.6% used beta-blocker (heart rate, 81.2% x heart rhythm, 58.8%; p < 0.05). Heart rate control was the most used treatment strategy (79.5% x 20.5%; p < 0.001). A statistical tendency towards more patients with ventricular dysfunction (15.2% x 2.9%; p = 0.06), CHADS2 > 2 (60.5% x 39.5%; p = 0.07) and heart valve diseases (25.8% x 11.8%; p = 0.08) was observed in the heart rate control group. CONCLUSION: In that population at high risk for thromboembolic events, the heart rate control strategy was the most used.

FUNDAMENTO: A despecho de la elevada prevalencia y importancia clínica de la Fibrilación Atrial (FA), no existen hasta el momento publicaciones brasileñas informando el perfil clínico y la estrategia de tratamiento (control de ritmo vs. control de frecuencia cardíaca) más utilizada en ese universo de pacientes. OBJETIVO: Evaluar la estrategia de tratamiento más empleada en la FA en ambulatorio especializado en el manejo de esa enfermedad. Secundariamente, se buscó describir el perfil clínico de esa población. MÉTODOS: Estudio transversal que evaluó secuencialmente, en 167 portadores de FA, la estrategia de tratamiento más empleada, así como el perfil clínico de esos pacientes. Se utilizó cuestionario estandarizado para recolección de datos. El análisis estadístico fue realizado por medio del software SPSS® versión 13.0. RESULTADOS: En esa población de alto riesgo para eventos tromboembólicos (61% con escore CHADS2 > 2), en que 54% de los individuos presentaban fibrilación atrial paroxística o persistente, 96,6% utilizaban antagonistas de la vitamina K o AAS, y 76,6% hacían uso de betabloqueante (81,2% frecuencia x 58,8% ritmo, p < 0,05); la estrategia de control de frecuencia fue la más empleada (79,5% x 20,5%, p < 0,001). Hubo una tendencia estadística la mayor agrupamiento de pacientes con disfunción ventricular (15,2% x 2,9%; p = 0,06), CHADS2 > 2 (60,5% x 39,5%; p = 0,07) y valvulopatías (25,8% x 11,8%; p = 0,08) en el segmento de control de la frecuencia. CONCLUSION: En esa población de alto riesgo para eventos tromboembólicos, la estrategia de control de frecuencia cardíaca fue la más empleada.

Pupil cycle time and contrast sensitivity in type II diabetes mellitus patients: A pilot study.

Context: Pupil cycle time (PCT) has been widely used for examination of ocular diabetic autonomic neuropathy (DAN). Aims: The primary aim of this study was to evaluate the difference of contrast sensitivity according to PCT results, and the secondary aim was to determine the factors associated with PCT difference for type II diabetes patients. Settings and Design: A clinical pilot study that included a total of 60 eyes of 60 type II diabetes patients. Materials and Methods: We divided all patients into three groups according to PCT results. Group A and Group C were composed of patients who had upper one third PCT and lower one third PCT, respectively. We analyzed difference of age, diabetes duration, hypertension duration, mean best corrected visual acuity (BCVA), mean spherical equivalent (SE), HbA1C, glomerular filtration rate (GFR), stage of diabetic retinopathy, and Cardiac Autonomic Function Score (CAFS). Contrast sensitivity and decrease of visual acuity by glare were also estimated and analyzed for 28 eyes of 28 non-proliferative diabetic retinopathy (NPDR) patients. Group [NPDR] A and Group [NPDR] C were defined as those who had lower one third PCT and upper one third PCT, respectively. Statistical Analysis: Statistical analysis was done using SPSS 17.0 software. Results and Conclusions: Each group contained 20 eyes. Significant differences between Group A and Group C were observed in duration of diabetes and CAFS (P ≤ 0.001 and P <0.001, respectively). Contrast sensitivity in Group [NPDR] A was significantly more than in Group [NPDR] C at all cpds (all P ≤ 0.001). We found that PCT can influence contrast sensitivity or glare in diabetes patients and also confirmed a significant correlation of PCT with CAFS and duration of diabetes.

Postmortem genetic testing in sudden cardiac death due to ion channelopathies / 法医学杂志

Sudden cardiac death accounts for majority of deaths in human. Evident cardiac lesions that may explain the cause of death can be detected in comprehensive postmortem investigation in most sudden cardiac death. However, no cardiac morphological abnormality is found in a considerable number of cases although the death is highly suspected from cardiac anomaly. With the advances in the modern molecular biology techniques, it has been discovered that many of these sudden deaths are caused by congenital ion channelopathies in myocardial cell, i.e., Brugada syndrome, long QT syndrome, catecholaminergic polymorphic ventricular tachycardia, and short QT syndrome, etc. This article presents the molecular genetics, electrocardiographic abnormalities, clinical manifestations, and mechanisms leading to sudden cardiac death with emphasis on the role of postmortem genetic testing in certification of cause of death. It may provide helpful information in investigating sudden cardiac death due to ion channelopathies in medico-legal practice.

Characteristics of P wave in Patients with Sinus Rhythm after Maze Operation

Maze operation could alter P wave morphology in electrocardiogram (ECG), which might prevent exact diagnosis of the cardiac rhythm of patients. However, characteristics of P wave in patients with sinus rhythm after the operation have not been elucidated systematically. Consecutive patients who underwent the modified Cox Maze operation from January to December 2007 were enrolled. The standard 12-lead ECG and echocardiography were evaluated in patients who had sinus rhythm at 6 months after the operation. The average axis of P wave was 65+/-30 degrees. The average amplitude of P wave was less than 0.1 mV in all 12-leads, with highest amplitude in V1. The most common morphology of P wave was monophasic with positive polarity (49%), except aVR lead, which was different from those in patients with enlarged left atrium, characterized by large P-terminal force in the lead V1. There were no significant differences in P-wave characteristics and echocardiographic parameters between patients with LA activity (30.6%) versus without LA activity (69.4%) at 6 months after the operation. In conclusion, the morphology of P wave in patients after Maze operation shows loss of typical ECG pattern of P mitrale: P wave morphology is small in amplitude, monophasic and with positive polarity.

Prevalencia del intervalo QT prolongado en diferentes patrones electrocardiográficos: estudio por teleelectrocardiografía / Increased Q-T interval in different electrocardiographic patterns: a remote recording electrocardiographic study

Introducción: El intervalo QT prolongado ha sido identificado como factor de riesgo de arritmias ventriculares incluso en personas aparentemente sanas. El objetivo de este estudio fue establecer la prevalencia de QTc prolongado en electrocardiogramas normales, con bloqueo completo de rama (BCR) y con crecimiento de ventrículo izquierdo (HVI). Métodos y Resultados: Se consideró como prolongado un valor > 440 mseg, en cada una de 4 derivaciones: D1, aVL, V5 y V6, consensuado por dos observadores. El grupo 1 estuvo formado por 8.459 trazados normales: de ellos un 84 por ciento tenían un QTc normal y un 16 por ciento tenían un QTc prolongado. El grupo 2 consistió en 2.647 trazados con bloqueo completo de rama, 532 trazados con bloqueo completo de rama izquierda (BCRI) y 2.115 con bloqueo completo de rama derecha (BCRD). De los BCRI un 51,5 por ciento de los trazados tenían QTc prolongado, lo cual observamos sólo en un 25 por ciento de los trazados con BCRD. El grupo 3 estuvo conformado por 2.503 trazados con HVI, 377 por criterio de voltaje (grupo 3a), 1.083 por criterio de voltaje y alteración de repolarización (grupo 3b) y 1.043 HVI sólo por criterio de alteración de repolarización (grupo 3c). Un 28 por ciento de las HVI por criterio de voltaje (grupo 3a) y un 29 por ciento de HVI por alteración de repolarización (grupo 3c) tenían un QTc prolongado. De las HVI por voltaje y alteración de repolarización (grupo 3b) un 42 por ciento tenían QTc prolongado. De las HVI con QTc largo, un 7.6 por ciento tenían QTc > 500 mseg. Al desglosar las HVI por grupos el grupo 3a tenía 4,7 por ciento de los trazados con QTc largo > 500 mseg, el grupo 3b un 7,9 por ciento y el grupo 3c, un 8.3 por ciento. Conclusiones: Se concluye la alta prevalencia de QTc prolongado incluso en ECG con morfología normal, pero especialmente en BCRI y en HVI por voltaje más alteraciones de repolarización. La prolongación de QTc en BCR no mostró correlación con la ...

Background. Increased Q-T interval has been identified as a risk factor for ventricular arrhythmia including normal subjects. Aim. To establish the prevalence of an increased QTc in normal electrocardiograms (N) an in those with complete bundle branch block (RBBB or LBBB) or left ventricular hypertrophy (L VH). Method. D1, aVL, V5 and V6 leads were analyzed; a > 440ms QTC agreed upon by 2 observers was considered prolonged. Results: an increased QTc was observed in 16 percent> of 8459 N subjects, 51.5 percent> of subjects with LBBB and 25 percent of those with RBBB. Among subjects with LVH, 28 percent of those with voltage only criteria for LVH and 29 percent of those with ST-T changes but no voltage criteria had increased QTc. In contrast, 42 percent> of patients with LVH exhibiting both diagnostic criteria had increased QTc. In 7.6 percent> of LVH subjects with increased QTc, this interval was >500ms, which broke down as follows: LVH by voltage criteria alone 4.7 percent>, ST-T changes alone 7.9 percent > and LVH with both voltage and ST-T criteria 8.3 percent>. In patients with complete bundle branch block, the duration of the QRS interval was not related to QTc. Conclusion. A prolonged QTc is a frequent finding in normal ECGs, much more so in subjects with LVH associated to voltage and ST-T criteria. The prognostic impact of a prolonged QTc in patients with complete bundle branch block deserves further study.

Remodelagem atrial elétrica reversa após cardioversão de fibrilação atrial isolada de longa duração / Remodelación atrial eléctrica reversa tras cardioversión de fibrilación atrial aislada de larga duración / Reversal atrial electrical remodeling following cardioversion of long-standing lone atrial fibrillation

FUNDAMENTO: A fibrilação atrial (FA) isolada promove mudanças eletrofisiológicas, chamadas de "remodelamento elétrico", facilitando sua recorrência e manutenção. Há evidência de que o processo de remodelamento seja reversível após a recuperação do ritmo sinusal (RS). Entretanto, o momento para a recuperação das propriedades eletrofisiológicas ainda não foi definido. OBJETIVO: O objetivo desse estudo foi avaliar a ativação elétrica atrial usando o eletrocardiograma de alta resolução de onda P (P-ECGAR) pós-cardioversão da FA de longa duração, concentrando-se no processo de remodelamento reverso para identificar o momento da estabilização do processo. MÉTODOS: Indivíduos com FA isolada persistente, candidatos à cardioversão com conversão bem-sucedida ao RS, foram incluídos no estudo. A P-ECGAR foi realizada imediatamente após a reversão ao ritmo sinusal e repetida após 7 e 30 dias. RESULTADOS: Dentre os 31 indivíduos, 9 apresentaram recorrência precoce da FA, todos nos primeiros 7 dias após a cardioversão, e 22 permaneceram em RS por pelo menos um mês; o ECGAR foi obtido no sétimo e no trigésimo dias após a cardioversão. No 30º dia, a duração da onda P progressivamente diminuiu do primeiro para o terceiro ECGAR (duração da onda P: 185,5±41,9 m/s vs 171,7±40,5 m/s vs 156,7±34,9 m/s, respectivamente, 1º, 2º e 3º ECGAR; p<0,001 para todas as comparações). Na análise de domínio de frequência, a turbulência espectral não foi aparente no ECGAR imediatamente após a cardioversão, mas aumentou de forma aguda no 7º dia e permaneceu inalterada no 30º dia. CONCLUSÃO: O presente estudo sugere que os primeiros sete dias pós-cardioversão, após FA de longa duração, são críticos para o processo de remodelamento reverso e recorrência da arritmia.

BACKGROUND: Atrial fibrillation (AF) itself promotes electrophysiological changes, termed "electrical remodeling", facilitating its recurrence and maintenance. There is evidence that the remodeling process is reversible after restoration of the sinus rhythm (SR). However, the timing for the recovery of electrophysiological properties is still undefined. OBJECTIVE: The aim of this study was to assess the atrial electrical activation using P-wave signal-averaged electrocardiogram (P-SAECG) post-cardioversion of long-standing AF, focusing on the reversal remodeling process to identify the timing of the process stabilization. METHODS: Subjects with lone persistent AF, eligible for cardioversion and successfully converted to SR, were enrolled at the study. SAECG was performed immediately after reversion to SR and repeated on days seven and thirty. RESULTS: Of 31 subjects, nine presented early recurrence of atrial fibrillation, all of them in the first seven days post-cardioversion; 22 remained in SR for at last one month and SAECG was obtained on days seven and thirty after cardioversion. In the latter, P-wave duration progressively abated from the first to the third SAECG (P-wave duration: 185.5±41.9 ms vs 171.7±40.5 ms vs 156.7±34.9 ms, respectively, first, second and third SAECG; p<0.001 for all matches). In the frequency domain analysis, spectral turbulence was not apparent in SAECG immediately post-cardioversion, but sharply increased on day seven and remained unchanged on day thirty. CONCLUSION: This study suggests that the first seven days post-cardioversion of long standing AF are critical for reversal remodeling process and arrhythmia recurrence.

FUNDAMENTO: La fibrilación atrial (FA) aislada promueve cambios electrofisiológicos llamados "remodelación eléctrica", que facilitan su recurrencia y mantenimiento. Hay evidencia de que el proceso de remodelación sea reversible tras la recuperación del ritmo sinusal (RS). Sin embargo, el momento para la recuperación de las propiedades electrofisiológicas no está definido todavía. OBJETIVO: El objetivo de ese estudio fue evaluar la activación eléctrica atrial con el empleo del electrocardiograma de alta resolución de onda P (P-ECGAR) postcardioversión de la FA de larga duración, concentrándose en el proceso de remodelación reversa para identificar el momento de la estabilización del proceso. MÉTODOS: Se incluyeron en el estudio a individuos con FA aislada persistente y a candidatos a la cardioversión con conversión exitosa al RS. La P-ECGAR se realizó inmediatamente tras la reversión al ritmo sinusal y se repitió después de 7 y 30 días. RESULTADOS: Entre los 31 individuos, 9 presentaron recurrencia precoz de la FA, todos en los primeros 7 días después de la cardioversión, y 22 siguieron en RS durante un mes como mínimo; el ECGAR se obtuvo en el séptimo y en el trigésimo días tras la cardioversión. En el 30º día, la duración de la onda P disminuyó progresivamente desde el primer hasta el tercer ECGAR (duración de la onda P: 185,5±41,9 m/s vs 171,7±40,5 m/s vs 156,7±34,9 m/s, respectivamente, 1er, 2º y 3er ECGAR; p<0,001 para todas las comparaciones). En los análisis de dominio de frecuencia, la turbulencia espectral no fue aparente en el ECGAR inmediatamente tras la cardioversión, pero aumentó de forma aguda en el 7º día y siguió inalterada en el 30º día. CONCLUSIÓN: El presente estudio sugiere que los primeros siete días post cardioversión, después FA de larga duración, son críticos para el proceso de remodelación reversa y recurrencia de la arritmia.

Circadian cardiac autonomic function in perinatally HIV-infected preschool children

The 24-h heart rate variability and QT-interval adaptation was investigated in perinatally HIV-infected preschool children classified according to immunological status in order to assess autonomic function at early stages of infection. Thirty-five perinatally HIV-infected and clinically stable children (4.8 ± 0.3 years) were enrolled after approval of the study by the University Hospital Pedro Ernesto Ethics Committee and written informed parental consent was obtained. The children were classified according to peripheral CD4+ count (cells/µL) as follows: group 1, N = 11 (≥1000); group 2, N = 7 (≥500 and <1000); group 3, N = 17 (<500). Left ventricular ejection fraction (>55%), 24-h RR interval variability (RRV) indexes (NN, SDANN, SDNN index, r-MSSD) and 24-h QT and Bazett-corrected QT (QTc) were determined, and groups were matched for age, body surface area, and left ventricular ejection fraction, reducing biases in RRV. The peak differences (∆) between the highest and lowest RRV and QT indexes were extracted from nocturnal (1 am-6 am) and daytime (1 pm-6 pm) hourly assessed segments, respectively. Pearson’s correlation (r) and Kruskal-Wallis ANOVA were used to compare groups. CD4+ count correlated positively with ∆NN (r = 0.45; P = 0.003). There were no significant differences in daytime NN among groups. Nighttime SDNN index (P = 0.01), nighttime r-MSSD (P = 0.003), ∆NN (P = 0.01), ∆SDNN index (P = 0.03) and ∆r-MSSD (P = 0.004) were significantly lower in group 3 than in the other groups. Expected nighttime QTc-interval lengthening was not observed in all groups. In perinatally HIV-infected preschool children with preserved left ventricular systolic function, parasympathetic-mediated autonomic dysfunction parallels immune status, impairing both RRV and circadian QTc interval adaptation.