Método rápido para determinar el eje cardíaco con D1 y D3 / Fast method to determine the cardiac axis with D1 and D3

El eje cardíaco representa el promedio de la dirección del proceso de activación eléctrica de las células cardíacas, es uno de los parámetros que debe determinarse en la correcta lectura e interpretación del electrocardiograma y es útil no solo como criterio diagnóstico de cardiopatías, sino también como marcador de pronóstico y mortalidad de otras enfermedades. Con el paso de los años han surgido nuevas fórmulas que permiten calcular con mayor exactitud su valor. El método que utiliza D1 y aVF es uno de los más populares, sin embargo, presenta dos puntos no medibles. El primero es entre 0 y -30 grados, y el segundo entre los valores de 90 y 110 grados. Aunque existen propuestas con algoritmos que utilizan otras derivaciones, se exploró un método alternativo con D1 y D3 basados en la fórmula algebraica de la tangente inversa y método matemático para el cálculo exacto del eje cardíaco. Se destaca este como una propuesta de método rápido que mantiene la confiabilidad de la fórmula algebraica para determinar si el eje cardíaco se encuentra dentro de los rangos normales (-30 a 110 grados)

The cardiac axis represents the average of the direction of the electrical activation process of the cardiac cells. It is one of the parameters determined in the correct reading and interpretation of the electrocardiogram. Also, not only is it useful as a diagnostic criterion for heart disease but also as a marker of prognosis and mortality in other diseases. Over the years, new formulas have emerged that allow its value to be calculated more accurately. The method using D1 and aVF is one of the most popular. However, it has two unmeasurable points. The first is between 0 and -30 degrees, and the second is between the values of 90 and 110 degrees. Although there are proposals with algorithms that use other leads, an alternative method was explored with D1 and D3 based on the algebraic formula of the inverse tangent and mathematical method for the exact calculation of the cardiac axis. A quick method is proposed that maintains the reliability of the algebraic formula to determine if the cardiac axis is within the normal ranges (-30 to 110 degrees)

Importancia de la sincronía aurículo-ventricular para el gasto cardíaco en un paciente con insuficiencia cardíaca y fracción de eyección reducida / Importance of atrioventricular synchrony for cardiac output in a patient with heart failure and reduced ejection fraction

RESUMEN Hombre de 80 años de edad, con antecedentes de miocardiopatía dilatada de origen isquémico, con disfunción sisto-diastólica del ventrículo izquierdo, que inicialmente presentó flutter auricular con inestabilidad hemodinámica y se realizó cardioversión eléctrica, luego de la cual se obtuvo un ritmo no precedido de onda P a 40 latidos por minuto, que fue interpretado como fibrilación auricular bloqueada; razón por la que se le colocó un marcapasos externo. Durante su evolución se realizó electrocardiograma de 12 derivaciones, donde se evidenció estimulación ventricular permanente con conducción retrógrada (ventrículo-auricular). Se disminuyó la frecuencia de estimulación para priorizar el ritmo espontáneo del paciente y se obtuvo marcada mejoría de la curva de presión arterial.

ABSTRACT An 80-year-old male patient is presented, with previous dilated cardiomyopathy of ischemic etiology, with systo-diastolic left ventricular dysfunction, who initially presented atrial flutter and hemodynamic instability, thus, an electrical cardioversion was performed. After this procedure, a blocked atrial fibrillation was observed. Thus, an external pacemaker was placed. During the evolution, a 12 lead electrocardiogram was performed, showing permanent ventricular stimulation with retrograde conduction (ventriculo-atrial). The pacing rate was diminished for prioritizing the patient's spontaneous rhythm resulting in an improvement of the blood pressure curve.

Research progress of pulse wave velocity applied in cardiovascular diseases / 中国基层医药

Cardiovascular diseases have become the most common and most prevalent chronic diseases in the elderly.Smoking, hyperlipidemia, diabetes and other high-risk factors participate in the occurrence and development of atherosclerosis by impairing the structure and function of the vascular wall, resulting in the occurrence of arterial stiffness.Pulse wave conduction velocity(PWV) is the rate at which a pulse wave travels from one specific location of the artery to another specific location along the wall of the artery.It is a simple, effective and repeatable noninvasive index for evaluating arterial elasticity and vascular function.PWV is closely related to cardiovascular disease.In recent years, the relationship between PWV and cardiovascular disease has been deeply studied.The relationship between PWV and coronary heart disease, hypertension, cardiac function, atrial fibrillation and pulmonary hypertension is described in this paper.

Research progress of pulse wave velocity applied in cardiovascular diseases / 中国基层医药

Cardiovascular diseases have become the most common and most prevalent chronic diseases in the elderly.Smoking,hyperlipidemia,diabetes and other high －risk factors participate in the occurrence and development of atherosclerosis by impairing the structure and function of the vascular wall ,resulting in the occurrence of arterial stiffness.Pulse wave conduction velocity (PWV) is the rate at which a pulse wave travels from one specific location of the artery to another specific location along the wall of the artery.It is a simple,effective and repeatable noninvasive index for evaluating arterial elasticity and vascular function.PWV is closely related to cardiovascular disease.In recent years,the relationship between PWV and cardiovascular disease has been deeply studied.The relationship between PWV and coronary heart disease , hypertension, cardiac function, atrial fibrillation and pulmonary hypertension is described in this paper.

Baseline Prolonged PR Interval and Outcome of Cardiac Resynchronization Therapy: A Systematic Review and Meta-analysis / Intervalo PR Basal Prolongado e Desfecho da Terapia de Ressincronização Cardíaca: Revisão Sistemática e Meta-Análise

Abstract Background: Recent studies suggest that baseline prolonged PR interval is associated with worse outcome in cardiac resynchronization therapy (CRT). However, a systematic review and meta-analysis of the literature have not been made. Objective: To assess the association between baseline prolonged PR interval and adverse outcomes of CRT by a systematic review of the literature and a meta-analysis. Methods: We comprehensively searched the databases of MEDLINE and EMBASE from inception to March 2017. The included studies were published prospective or retrospective cohort studies that compared all-cause mortality, HF hospitalization, and composite outcome of CRT with baseline prolonged PR (> 200 msec) versus normal PR interval. Data from each study were combined using the random-effects, generic inverse variance method of DerSimonian and Laird to calculate the risk ratios and 95% confidence intervals. Results: Six studies from January 1991 to May 2017 were included in this meta-analysis. All-cause mortality rate is available in four studies involving 17,432 normal PR and 4,278 prolonged PR. Heart failure hospitalization is available in two studies involving 16,152 normal PR and 3,031 prolonged PR. Composite outcome is available in four studies involving 17,001 normal PR and 3,866 prolonged PR. Prolonged PR interval was associated with increased risk of all-cause mortality (pooled risk ratio = 1.34, 95 % confidence interval: 1.08-1.67, p < 0.01, I2= 57.0%), heart failure hospitalization (pooled risk ratio = 1.30, 95 % confidence interval: 1.16-1.45, p < 0.01, I2= 6.6%) and composite outcome (pooled risk ratio = 1.21, 95% confidence interval: 1.13-1.30, p < 0.01, I2= 0%). Conclusions: Our systematic review and meta-analysis support the hypothesis that baseline prolonged PR interval is a predictor of all-cause mortality, heart failure hospitalization, and composite outcome in CRT patients.

Resumo Fundamento: Estudos recentes sugerem que intervalo PR basal prolongado está associado a prognóstico ruim para a terapia de ressincronização cardíaca (TRC). No entanto, nunca foram feitas uma revisão sistemática e meta-análise da literatura. Objetivo: Avaliar a associação entre intervalo PR basal prolongado e resultados adversos da TRC por meio de uma revisão sistemática e meta-análise da literatura. Métodos: Pesquisamos de forma abrangente os bancos de dados MEDLINE e EMBASE, desde o início até março de 2017. Os estudos incluídos eram de coorte prospectivos ou retrospectivos que comparavam mortalidade por todas as causas, hospitalização por insuficiência cardíaca e desfecho composto por TRC com PR basal prolongado (> 200 ms) versus intervalo PR normal. Os dados de cada estudo foram combinados pelo modelo de efeitos aleatórios, variância genérica inversa de DerSimonian e Laird para calcular as razões de risco e os intervalos de confiança de 95% (IC95%). Resultados: Foram incluídos seis estudos de janeiro de 1991 a maio de 2017 nesta metanálise. A taxa de mortalidade por todas as causas foi mencionada em quatro estudos envolvendo 17.432 intervalos PR normais e 4.278 prolongados. Hospitalização por insuficiência cardíaca foi abordada em dois estudos envolvendo 16.152 PR normais e 3.031 prolongados. Desfecho composto esteve presente em quatro estudos com 17.001 PR normais e 3.866 prolongadas. Intervalo PR prolongado foi associado a risco aumentado de mortalidade por todas as causas (razão de risco agrupado = 1,34, IC95%: 1,08-1,67, p < 0,01, I2= 57,0%), hospitalização por insuficiência cardíaca (razão de risco agrupado = 1,30, 95 % de IC95%: 1,16-1,45, p < 0,01, I2= 6,6%) e desfecho composto (razão de risco agrupado = 1,21, IC95%: 1,13-1,30, p < 0,01, I2= 0%). Conclusões: Nossa revisão sistemática e metanálise suportam a hipótese de que o intervalo PR basal prolongado é um preditor de mortalidade por todas as causas, hospitalização por insuficiência cardíaca e desfecho composto em pacientes submetidos à TRC.

Unsolved Questions on the Anatomy of the Ventricular Conduction System

We reviewed the anatomical characteristics of the conduction system in the ventricles of human and ungulate hearts and then raised some questions to be answered by clinical and anatomical studies in the future. The ventricular conduction system is a 3-dimensional structure as compared to the 2-dimensional character of the atrial conduction system. The proximal part consisting of the atrioventricular node, the bundle of His and fascicles are groups of conducting cells surrounded by fibrous connective tissue so as to insulate from the underlying myocardium. Their location and morphological characters are well established. The bundle of His is a cord like structure but the left and right fascicles are broad at the proximal and branching at the distal part. The more distal part of fascicles and Purkinje system are linear networks of conducting cells at the immediate subendocardium but the intra-mural network is detected at the inner half of the ventricular wall. The papillary muscle also harbors Purkinje system not in the deeper part. It is hard to recognize histologically in human hearts but conducting cells as well as Purkinje cells are easily recognized in ungulate hearts. Further observation on human and ungulate hearts with myocardial infarct, we could find preserved Purkinje system at the subendocardium in contrast to the damaged system at the deeper myocardium. Further studies are necessary on the anatomical characteristics of this peripheral conduction system so as to correlate the clinical data on hearts with ventricular arrhythmias.

Distúrbios de condução cardíaca e taquicardia ventricular como complicação da granulomatose com poliangiíte em uma paciente. Relato de caso e revisão da literatura / Heart conduction system defects and sustained ventricular tachycardia complications in a patient with granulomatosis with polyangiitis. A case report and literature review

RESUMO A granulomatose com poliangiíte é um raro distúrbio inflamatório sistêmico que se caracteriza por vasculite de pequenas artérias, arteríolas e capilares, associada a lesões granulomatosas necrotizantes. Este artigo relata o caso de uma paciente com diagnóstico prévio de granulomatose com poliangiíte, admitida à unidade de terapia intensiva com quadro de crises convulsivas e instabilidade hemodinâmica em razão de bloqueio atrioventricular completo. Estas manifestações se associaram a múltiplos episódios de taquicardia ventricular sustentada; não havia alterações estruturais cardíacas, nem se detectaram distúrbios hidroeletrolíticos. Na unidade de terapia intensiva, a paciente foi submetida à implantação de marca-passo provisório, imunossupressão com uso de corticosteroides e terapia imunobiológica, resultando em melhora hemodinâmica completa. Distúrbios graves da condução cardíaca em pacientes com granulomatose com poliangiíte são raros, mas associam-se à grande morbidade. O reconhecimento precoce e o uso de intervenções específicas são capazes de prevenir a ocorrência de desfechos desfavoráveis, especialmente na unidade de terapia intensiva.

ABSTRACT Granulomatosis with polyangiitis is a rare systemic inflammatory disorder characterized by vasculitis of the small arteries, the arterioles and the capillaries together with necrotizing granulomatous lesions. This case reports on a young female patient, previously diagnosed with granulomatosis with polyangiitis, who was admitted to the intensive care unit with seizures and hemodynamic instability due to a complete atrioventricular heart block. The event was associated with multiple episodes of sustained ventricular tachycardia without any structural heart changes or electrolyte disturbances. In the intensive care unit, the patient was fitted with a provisory pacemaker, followed by immunosuppression with corticosteroids and immunobiological therapy, resulting in a total hemodynamic improvement. Severe conduction disorders in patients presenting granulomatosis with polyangiitis are rare but can contribute to increased morbidity. Early detection and specific intervention can prevent unfavorable outcomes, specifically in the intensive care unit.

Prevention of Pazopanib-Induced Prolonged Cardiac Repolarization and Proarrhythmic Effects / Prevenção da Repolarização Cardíaca Prolongada e dos Efeitos Pró-arrítmicos Induzidos por Pazopanibe

Background: Pazopanib (PZP) may induce prolonged cardiac repolarization and proarrhythmic effects, similarly to other tyrosine kinase inhibitors. Objectives: To demonstrate PZP-induced prolonged cardiac repolarization and proarrhythmic electrophysiological effects and to investigate possible preventive effects of metoprolol and diltiazem on ECG changes (prolonged QT) in an experimental rat model. Methods: Twenty-four Sprague-Dawley adult male rats were randomly assigned to 4 groups (n = 6). The first group (normal group) received 4 mL of tap water and the other groups received 100 mg/kg of PZP (Votrient® tablet) perorally, via orogastric tubes. After 3 hours, the following solutions were intraperitoneally administered to the animals: physiological saline solution (SP), to the normal group and to the second group (control-PZP+SP group); 1 mg/kg metoprolol (Beloc, Ampule, AstraZeneca), to the third group (PZP+metoprolol group); and 1mg/kg diltiazem (Diltiazem, Mustafa Nevzat), to the fourth group (PZP+diltiazem group). One hour after, and under anesthesia, QTc was calculated by recording ECG on lead I. Results: The mean QTc interval values were as follows: normal group, 99.93 ± 3.62 ms; control-PZP+SP group, 131.23 ± 12.21 ms; PZP+metoprolol group, 89.36 ± 3.61 ms; and PZP+diltiazem group, 88.86 ± 4.04 ms. Both PZP+metoprolol and PZP+diltiazem groups had significantly shorter QTc intervals compared to the control-PZP+SP group (p < 0.001). Conclusion: Both metoprolol and diltiazem prevented PZP-induced QT interval prolongation. These drugs may provide a promising prophylactic strategy for the prolonged QTc interval associated with tyrosine kinase inhibitor use. .

Fundamento: Pazopanibe (PZP) pode induzir prolongamento da repolarização cardíaca e efeitos pró-arrítmicos, à semelhança de outros inibidores da tirosina quinase. Objetivos: Demonstrar prolongamento da repolarização cardíaca e efeitos eletrofisiológicos pró-arrítmicos induzidos pelo PZP, assim como investigar possíveis efeitos de metoprolol e diltiazem na prevenção de alterações no ECG (prolongamento do intervalo QT) em um modelo experimental em ratos. Métodos: Ratos Sprague-Dawley adultos machos (24) foram designados de modo aleatório para quatro grupos (n = 6). O primeiro grupo (normal) recebeu 4 ml de água da torneira, enquanto os demais receberam 100 mg/kg de PZP (comprimido de Votrient®) através de sonda orogástrica. Após 3 horas, os animais receberam por via intraperitoneal: solução salina, para o grupo normal e para o segundo grupo (controle-PZP+SP); 1 mg/kg de metoprolol (Beloc, Ampola, AstraZeneca), para o terceiro grupo (PZP+metoprolol); e 1mg/kg de diltiazem (Diltiazem, Mustafa Nevzat), para o quarto grupo (PZP+diltiazem). Uma hora após a administração desses medicamentos, e sob anestesia, calculou-se o intervalo QTc registrando-se o ECG em DI. Resultados: Os valores médios do intervalo QTc foram: grupo normal, 99,93 ± 3,62 ms; grupo controle-PZP+SP, 131,23 ± 12,21 ms; grupo PZP+metoprolol, 89,36 ± 3,61 ms; e grupo PZP+diltiazem, 88,86 ± 4,04 ms. Os grupos PZP+metoprolol e PZP+diltiazem apresentaram intervalos QTc significativamente mais curtos comparados aos do grupo controle-PZP+SP (p < 0,001). Conclusão: Ambos metoprolol e diltiazem evitaram o prolongamento do intervalo QT induzido por PZP. Tais medicamentos podem ser uma promissora estratégia para evitar o prolongamento do intervalo QTc associado ao uso de inibidores da tirosina quinase. .

Complicaciones eléctricas posimplante de válvula aórtica percutáneo: evolución clínica y eléctrica / Clinical Outcomes of Electrical Disorders after Transcatheter Aortic Valve Implantation

Introducción El implante valvular aórtico percutáneo es una opción terapéutica cada vez más utilizada en pacientes en los que se descarta la cirugía. A pesar de que las alteraciones agudas de la conducción son una de las complicaciones más frecuentes, su significado clínico y electrocardiográfico no es del todo claro. Objetivos Determinar las implicaciones pronósticas del desarrollo de alteraciones agudas de la conducción luego del implante valvular aórtico percutáneo. Resultados Entre marzo de 2009 y febrero de 2012 se incluyeron para el análisis 47 pacientes; de ellos, 30 (63%) presentaron alteraciones agudas de la conducción: 19 pacientes solo bloqueo completo de rama izquierda (BCRI), 9 pacientes solo bloqueo auriculoventricular completo (BAVC) y 2 pacientes presentaron ambos trastornos, los que totalizaron 21 BCRI y 11 BAVC. A 12 (25%) se les implantó un marcapasos definitivo previo al alta: en 11 por BAVC y en 1 por BCRI agudo más fibrilación auricular. En solo un paciente el BAVC revirtió en hemodinamia. Los pacientes que persistieron con BAVC posintervención presentaron una media de estimulación ventricular en la intervalometría al mes del 90%, mientras que en el paciente con BAVC que revirtió en hemodinamia fue de solo el 3% y en el paciente con BCRI más fibrilación auricular fue < 10%. La incidencia de insuficiencia cardíaca en el posoperatorio fue mayor en los pacientes con alteraciones agudas de la conducción (p = 0,007), al igual que la estadía hospitalaria (p = 0,045). En el seguimiento no hubo diferencias en la tasa de reinternación ni en la mortalidad. Conclusiones En el presente estudio el desarrollo de alteraciones agudas de la conducción mostró un aumento en la incidencia de insuficiencia cardíaca y en los días de internación, sin incremento en la tasa de otros eventos mayores. La colocación de un marcapasos definitivo luego del BAVC podría realizarse en forma inmediata, ya que el trastorno generalmente es irreversible.

Introduction The indication of transcatheter aortic valve implantation in patients considered not suitable candidates for surgery is increasing. Despite acute disorders of the conduction system are common complications, their clinical and electrocardiographic significance is not completely clear. Objectives To determine whether acute disorders of the conduction system after transcatheter aortic valve implantation has prognostic implications. Results Between March 2009 and February 2012, 47 patients were included in the analysis. Thirty patients (63%) had acute disorders of the conduction system: 19 patients presented isolated complete left bundle branch block (LBBB), 9 patients isolated complete atrioventricular block (CAVB), and 2 patients both conduction disorders, with a total of 21 LBBBs and 11 CAVBs. A definite pacemaker was implanted in 12 patients (25%) before discharge: in 11 due to CAVB and in 1 due to acute LBBB plus atrial fibrillation. Complete AVB reverted in the catheterization laboratory in only one patient. At one month, average ventricular pacing was 90% in patients with persistent CAVB after the intervention, only 3% in the only patient in whom CAVB reverted at the catheterization laboratory and < 10% in the patient with LBB plus atrial fibrillation. The incidence of postoperative heart failure and hospital stay was greater in patients with acute disorders of the conduction system (p = 0.007 and p = 0.045, respectively). There were no differences in new hospitalizations and mortality during follow-up. Conclusions In this study, the development of acute disorders of the conduction system was associated with increased incidence of heart failure and hospital stay but not with the incidence of major events. A definite pacemaker could be implanted immediately after CAVB develops as the conduction disorder is generally irreversible.

Variaciones de aa arteria del nodo sinoatrial en población Colombiana / Sino-atrial node artery variation in a sample of the Colombian population

Antecedentes. El conocimiento exacto de la integración anatomofisiológica del sistema de conducción del corazón, es fundamental para la comprender la fisiopatología, el diagnóstico y el manejo de muchas de las complicaciones de la enfermedad coronaria y de las cardiopatías en general. Uno de los aspectos fundamentales, más variable y con mayores repercusiones clínicas corresponde al origen y recorrido de las arterias encargadas de irrigar el nódulo sinoatrial. Objetivo. Determinar el origen, recorrido y distribución de las arterias que irrigan el nódulo sinoatrial en una muestra de población colombiana. Material y métodos. La muestra de análisis fueron 60 bloques cardiopulmonares y digestivos seleccionados a través de muestreo por conveniencia. A estos se les realizó una disección convencional de los genitales para la determinación del sexo y posteriormente se procedió con la disección de las arterias coronarias específicamente de la arteria del nódulo sinoatrial, con el fin de establecer su origen y recorrido. Resultados. Como hallazgo principal se encontró que el origen de la arteria del nódulo sinoatrial en 75% provenía de la coronaria derecha, un 15% procedía de la arteria circunfleja y el 10% restante fue codominante. En cuanto al trayecto 86,6% fueron lineales, mientras 13,4% tuvieron formas alternas como Y, doble Y o en tridente. Conclusiones. Se evidenció predominio del origen de la arteria del nódulo sinoatrial en la coronaria derecha, hallazgo coincidente con investigaciones similares e independiente de la procedencia geográfica y el origen racial. Sin embargo, en este estudio se evidenciaron recorridos no reportados en la literatura como la distribución en Y, en doble Y, en K invertida y en tridente.

Background. Accurate knowledge regarding the cardiac conduction system's anatomical-physiological integration is essential for understanding the pathophysiology, diagnosis and management of many complications regarding coronary disease and heart disease in general. One of the more variable fundamental aspects, having the greatest clinical impact, concerns the origin and course of arteries irrigating the sino-atrial node (SAN). Objective. Determining the origin, course and distribution of arteries supplying the SAN in a sample of the Colombian population. Materials and methods. 60 cardiopulmonary and digestive blocks were taken by convenience sampling. Conventional dissection of the genitalia determined gender; the coronary artery was then dissected, specifically the SAN, to establish origin and route. Results. It was found that 75% of the SAN artery's blood supply came from the right coronary artery (RCA), 15% from the circumflex artery and 10% was co-dominant. 86.6% of courses were linear; 13.4% were Y-shaped or Y-and double trident shaped. Conclusions. The prevalence of SAN artery origin in the RCA in this study was consistent with similar research findings, regardless of geographical and racial origin. However, this study report some courses not previously described in the literature, such as Y-, double Y-, inverted K- and trident-shaped forms.

Patologia do bloqueio atrioventricular na cardiomiopatia por depósito de desmina / Atrioventricular block pathology in cardiomyopathy by desmin deposition / Patología de bloqueo auriculoventricular en la miocardiopatía por depósito de desmina

Geralmente, a cardiomiopatia restritiva por deposição de desmina é caracterizada pela restrição ao enchimento diastólico ventricular e por diferentes graus de bloqueio atrioventricular (BAV). Neste relato, são descritas as alterações anatomopatológicas do sistema de condução cardíaco relacionadas ao BAV. O nó sinusal, o nó compacto e o feixe penetrante (feixe de His) não apresentavam anormalidades, entretanto, havia extensa fibrose das porções terminais do feixe ramificante e do início dos feixes esquerdo e direito, no topo do septo ventricular. A patogenia dessa substituição fibrosa é provavelmente a mesma que origina a extensa fibrose do miocárdio ventricular contrátil, e permanece por ser elucidada.

Generally, restrictive cardiomyopathy due to desmin deposition is characterized by restriction to ventricular diastolic filling and different degrees of atrioventricular block (AVB). In this report, we describe the pathological changes of the cardiac conduction system related to AVB. The sinus node, the compact node, and the penetrating bundle (bundle of His) had no abnormalities, however, there was extensive fibrosis of the terminal portions of the branching bundle and the beginning of the left and right bundles at the top of the ventricular septum. The pathogenesis of this fibrous replacement is probably the same that leads to extensive fibrosis of the working ventricular myocardium, and remains to be elucidated.

En general, la miocardiopatía restrictiva, debido a la deposición de desmina se caracteriza por la restricción de llenado diastólico ventricular y por los distintos grados de bloqueo auriculoventricular (BAV). En este informe, se describen los cambios anatómicos y patológicos del sistema de conducción cardiaco relacionado con BAV. El nodo sinusal, el nodo compacto y haz penetrante (haz de His) no tuvo alteraciones, sin embargo, había fibrosis extensa de las porciones terminales del haz en porción ramificante y del comienzo de los haces izquierda y derecha, en la parte superior del tabique ventricular. La patogenia de esta sustitución fibrosa es probablemente la misma que origina la fibrosis extensa del miocardio ventricular contráctil, y queda por dilucidar.

Avaliação eletrofisiológica cardíaca em pacientes com sarcoidose / Cardiac electrophysiological assessment in patients with sarcoidosis / Evaluación electrofisiológica cardíaca en pacientes con sarcoidosis

FUNDAMENTO: Sarcoidose é uma doença granulomatosa multissistêmica de origem desconhecida que pode causar morte súbita. OBJETIVO: Avaliação eletrofisiológica de pacientes com sarcoidose com suspeita de comprometimento cardíaco. MÉTODOS: Foram estudados 22 pacientes com média de idade de 55,32 ±13,13 anos, com diagnóstico de sarcoidose e suspeita de comprometimento cardíaco. Foram submetidos à avaliação clínica, exames laboratoriais, eletrocardiograma, ecocardiograma, Holter de 24h, cintilografia com gálio ou tecnécio e estudo eletrofisiológico. Em casos selecionados foi realizada tomografia por emissão de pósitrons ou ressonância magnética. Os pacientes foram seguidos ambulatoriamente com consultas trimestrais. RESULTADOS: Comprometimento cardíaco foi comprovado em quatro (18,2 por cento) pacientes. Extrassístoles ventriculares com densidade > 100/24h foram documentadas no Holter de 24h em 12 (54,5 por cento) pacientes. O estudo eletrofisiológico revelou aumento do intervalo HV em sete (31,8 por cento) e ponto de Wenckebach aumentado em quatro (18,2 por cento) pacientes. Houve indução de fibrilação atrial em sete (31,8 por cento) e de taquicardia ventricular sustentada em um (4,5 por cento). Nos quatro pacientes com sarcoidose cardíaca confirmada, extrassístoles ventriculares, com densidade > 100/24h foram documentadas em todos, dois apresentavam intervalo HV prolongado e fibrilação atrial foi induzida em dois. Taquicardia ventricular sustentada não foi induzida em nenhum desses pacientes. Após período médio de acompanhamento de 20,9 ± 15,7 meses, um paciente com sarcoidose cardíaca apresentou morte súbita. CONCLUSÃO: Pacientes com sarcoidose e suspeita de envolvimento cardíaco apresentam alta prevalência de EVs e distúrbios do sistema de condução.

BACKGROUND: Sarcoidosis is a multisystem granulomatous disease of unknown origin that can cause sudden death. OBJECTIVE: Electrophysiological evaluation of patients with suspected sarcoidosis with cardiac involvement. METHODS: We studied 22 patients with mean age of 55.32 ± 13.13 years, diagnosed with sarcoidosis and suspected cardiac involvement. These patients underwent clinical evaluation, laboratory tests, electrocardiogram, echocardiogram, 24-hour Holter, technetium or gallium scintigraphy and electrophysiological study. In selected cases, we performed positron emission tomography or magnetic resonance imaging. Patients were followed up in the outpatient care service with quarterly visits. RESULTS: Cardiac involvement was confirmed in four (18.2 percent) patients. Ventricular extrasystoles with density > 100/24h were documented in 24-Holter monitoring in 12 (54.5 percent) patients. Electrophysiological studies revealed an increased HV interval in seven patients (31.8 percent) and increased Wenckebach point in four (18.2 percent) patients. There was induction of atrial fibrillation in seven patients (31.8 percent) and sustained ventricular tachycardia in one patient (4.5 percent). Four patients with confirmed cardiac sarcoidosis had documented ventricular extrasystoles with density > 100/24h. Out of these, two had prolonged HV interval and atrial fibrillation was induced in two of them. Sustained ventricular tachycardia was not induced in any of these patients. After mean follow-up period of 20.9 ± 15.7 months, one patient with cardiac sarcoidosis had sudden death. CONCLUSION: Patients with sarcoidosis and suspected cardiac involvement have a high prevalence of ventricular extrasystoles (VEs) and conduction system disorders.

FUNDAMENTOS: Sarcoidosis es una enfermedad granulomatosa multisistémica de origen desconocido que puede causar la muerte súbita. OBJETIVOS:Evaluación electrofisiológica de los pacientes con sarcoidosis con sospecha de afectación cardíaca. MÉTODOS:Se estudiaron a 22 pacientes con una media de edad de 55,32 ± 13,13 años, con diagnóstico de sarcoidosis y sospecha de afectación cardíaca.Se sometieron a evaluación clínica, exámenes de laboratorio, electrocardiograma, ecocardiograma, Holter de 24 h, centellografía con galio o tecnecio y estudio electrofisiológico. En los casos seleccionados se realizó tomografía por emisión de positrones o la resonancia magnética.Los pacientes fueron seguidos en ambulatorio, en consultas trimestrales. RESULTADOS:La afectación cardíaca se comprobó en cuatro (18,2 por ciento) pacientes.Extrasístoles ventriculares con densidad > 100/24 h se documentaron en el Holter de 24 h en 12 (54,5 por ciento) pacientes.Los estudios electrofisiológicos revelaron un aumento del intervalo HV en siete (31,8 por ciento) y punto de Wenckebach aumentado en cuatro (18,2 por ciento) pacientes. No hubo inducción de fibrilación auricular en siete (31,8 por ciento) y de taquicardia ventricular sostenida en uno (4,5 por ciento). En los cuatro pacientes con sarcoidosis cardiaca confirmada, extrasístoles ventriculares (EVs), con densidad > 100/24 h se documentaron en todos, dos presentaban prolongación del intervalo HV y fibrilación auricular se indujo en dos. La taquicardia ventricular sostenida no fue inducida en cualquiera de estos pacientes. Después de un periodo medio de seguimiento de 20,9 ± 15,7 meses, un paciente con sarcoidosis cardíaca tuvo muerte súbita. CONCLUSIÓN: Los pacientes con sarcoidosis y sospecha de afectación cardíaca tienen una alta prevalencia de EVs y trastornos del sistema de conducción.

Electrophysiological effects of ibutilide on normal cardiac conduction system and accessory pathways / 第二军医大学学报

Objective: To observe the electrophysiological effects of ibutilide on the normal cardiac conduction system and accessory pathways (AP) of patients with accessory pathways mediated reentrant tachycardia (AVRT) and to assess the safety of ibutilide in electrophysiology study (EPS) and radiofrequency catheter ablation (RFCA). Methods: Twenty-one patients with AVRT undergoing EPS received intravenous ibutilide (1 mg). Electrophysiological parameters, including P-A interval, A-H interval, H-V interval, QRS complex width, QT interval, paced QT interval, right atrial effective refractory period (RA ERP), right ventricular ERP (RV ERP)q atrioventricular node ERP (AVN ERP), AVN block cycle length (AVN BCD, antegrade AP ERP and retrograde AP ERP 9 were observed before and instantly, 15 min, and 30 min after injection of ibutilide. Results: There was no statistical difference in the P-A interval, A-H interval, H-V interval and QRS complex width before and after ibutilide injection(P>0.05). After injection of ibutilide, the QTc, QT intervals, the RA ERP, RV ERP, and AVN BCL were all significantly prolonged (P<0.05). The antegrade and retrograde ERP of AP were also increased (P<0.05), with no loss of antegrade and retrograde function of AP. All patients underwent successful ablation and Torsade de pointes (Tdp) and no other adverse effects were noticed. Conclusion: Ibutilide has no effect on the conductivity of normal cardiac conduction system. Routine dosage of ibutilide can prolong ERP of AP but does not block the conductivity, with no influence on electrophysiology study and radiofrequency catheter ablation. Ibutilide has no adverse effect on patients with AVRT.

Cardiac resynchronization therapy in patients with heart failure: systematic review: [revi~ew] / Terapia de ressincronização cardíaca em pacientes com insuficiência cardíaca: revisão sistemática: [revisão]

CONTEXT AND OBJECTIVE: Cardiac resynchronization therapy (CRT) has emerged as the predominant electrical treatment strategy for patients on pharmacological therapy who present heart failure with wide QRS and low ejection fraction. The objective of this study was to investigate whether cardiac resynchronization therapy improved mortality and morbidity among patients with heart failure. METHODS: This was a systematic review using the Cochrane Collaboration's methodology. The online search strategy included the Cochrane Library, Medline (Medical Literature Analysis and Retrieval System Online), Lilacs (Literatura Latino-Americana e do Caribe em Ciências da Saúde) and cardiology congresses from 1990 to 2006. The criteria for considering studies for this review were as follows:-types of studies: randomized controlled trials; types of interventions: cardiac resynchronization therapy compared with other therapies; types of participants: patients with heart failure with low ejection fraction and wide QRS; outcomes: death or hospitalization. RESULTS: Seven trials met the selection criteria. The risk of death due to congestive heart failure was nonsignificant: relative risk (RR), 0.79; 95 percent confidence interval (CI): 0.60 to 1.03. There was an absolute risk reduction of 4 percent in all-cause mortality for the experimental group #&091;RR 0.70; CI: 0.60 to 0.83; number needed to treat (NNT) 25#&093;; sudden cardiac death showed a statistically significant difference favoring the experimental group, with absolute risk reduction of 1 percent (CI: 0.46 to 0.96; RR 0.67; NNT 100). There was an absolute risk reduction of 9 percent for hospitalization due to heart failure (RR 0.64; CI: 0.50 to 0.80; NNT 11) in the experimental group. CONCLUSIONS: Patients receiving CRT had a significantly lower risk of hospitalization due to heart failure, but death rates due to heart failure were similar.

CONTEXTO E OBJETIVO: A terapia de ressincronização cardíaca (TRC) surgiu como a estratégia de tratamento elétrico predominante para pacientes com insuficiência cardíaca com QRS largo e baixa fração de ejeção. O objetivo foi investigar se a terapia de ressincronização cardíaca melhora a mortalidade e morbidade dos pacientes com insuficiência cardíaca. MÉTODOS: Esta é uma revisão sistemática que utilizou a metodologia da Colaboração Cochrane. A estratégia de busca eletrônica incluiu a Biblioteca Cochrane, Medline, Lilacs e congressos de cardiologia de 1990 a 2006. Os critérios de inclusão foram os seguintes: tipos de estudos: estudos clínicos randomizados; tipos de intervenções: terapia de ressincronização cardíaca comparada com outras terapias; tipos de participantes: pacientes com insuficiência cardíaca com baixa fração de ejeção e QRS largo; desfechos: mortalidade, hospitalização. RESULTADOS: Sete estudos foram incluídos. O risco de morte devida à insuficiência cardíaca congestiva foi insignificante: risco relativo (RR) = 0.79; intervalo de confiança (IC) de 95 por cento = 0.60 a 1.03; houve redução de 4 por cento do risco absoluto de mortalidade por todas as causas no grupo experimental #&091;RR 0.70; IC: 0.60 a 0.83; número necessário para tratar (NNT) = 25#&093;; morte cardíaca súbita mostrou ter diferença estatisticamente significante favorável ao grupo experimental, com redução de 1 por cento do risco absoluto (IC: 0.46 a 0.96; RR 0.67; NNT= 100). Houve redução de 9 por cento do risco absoluto de hospitalização devido a insuficiência cardíaca (RR 0.64; IC: 0.50 a 0.80; NNT =11) no grupo experimental. CONCLUSÕES: Pacientes em TRC tiveram risco de hospitalização por falência cardíaca significativamente mais baixo, mas os índices de mortalidade por insuficiência cardíaca foram semelhantes.

Effect of remifentanil on QT dispersion / 대한마취과학회지

BACKGROUND: QT dispersion (QT(d)) is an indirect measure of the heterogeneity of ventricular repolarization and can be used as a risk factor for complex ventricular arrhythmias. We measured the effect of remifentanil on QT(d) and heart-rate corrected QT dispersion (QT(cd)). METHODS: Sixty ASA class I and II patients, who were between 20 and 60 years old, and who were scheduled for general anesthesia, were studied. After the patient entered the operating room, a 12 lead EKG recording was taken and intravenous infusion of remifentanil was started. The infusion rate was 0.1 microg/kg/min in group 1 and 0.2 microgram/kg/min in group 2. Another EKG recording was taken 10 minutes after infusion had started. RESULTS: In both groups, QT(d) following remifentanil infusion was not significantly different than control values (76.6 +/- 23.3 ms vs 81.8 +/- 34.9 ms, P = 0.459 in group 1; 70.7 ms +/- 29.7 ms vs 73.7 ms +/- 37.1 ms, P = 0.734 in group 2). Neither was QT(cd): (83.2 ms +/- 25.2 ms vs 89.6 ms +/- 36.2 ms, P = 0.371 in group 1; 81.0 ms +/- 35.2 ms vs 83.4 ms +/- 40.9 ms, P = 0.829 in group 2). CONCLUSIONS: Remifentanil infusion at a rate less than 0.2 microg/kg/min does not change QT(d) or QT(cd).

Quantitative study of fetal heart conduction time intervals by tissue Doppler imaging and pulse Doppler echocardiography / 中华超声影像学杂志

Objective To establish reference values of normal fetal heart conduction time intervals by tissue Doppler imaging(TDI)and pulsed Doppler(PD)echocardiography,and to assess their correlation with gestational-age and fetal heart rate.Methods One hundred and eighty-nine pregnant women underwent detailed echocardiographic examinations.Atrio-ventricular conduction time interval(AV)and the time interval from onset of ventricular contraction to the onset of atrial contraction of next cardiac cycle(VA)were measured by TDI and PD echocardiography.Results TDI-AV was(126.56±15.33)ms(95% CI 124.10～129.03 ms),TDI-VA was(285.22±24.53)ms(95% CI 281.27～289.16 ms),PD-AV was(127.42±12.88)ms(95% CI 125.35～129.49 ms),PD-VA was(287.42±25.19)ms(95% CI 283.37～291.47 ms).A paired t test revealed no systematic difference between the two approaches used to measure AV and VA.AV and VA were significantly positively correlated with gestational age,and significantly negatively correlated with fetal heart rate.Heart conduction time intervals were altered in fetus with paroxysmal arrhythmia.Conclusions This study established the normal values of fetal heart conduction time intervals.Prenatal determination of fetal heart conductional time intervals has important potential clinical utility in assessing fetal arrhythmia.

Estudo prospectivo das repercussões de baixas doses de remifentanil na função sinoatrial e na condução e refratariedade cardíaca / Prospective study on the repercussions of low doses of remifentanil on sinoatrial function and in cardiac conduction and refractory period

JUSTIFICATIVA E OBJETIVOS: O remifentanil é um opióide com início e término de ação rápidos, cujo uso em procedimentos de curta duração vem se propagando nos últimos anos. Entre os efeitos colaterais descritos, há relatos de bradicardia e assistolia. O objetivo deste estudo foi avaliar os efeitos desse fármaco na condução e refratariedade cardíaca, em humanos. MÉTODO: Estudo prospectivo de 16 pacientes, entre 18 e 65 anos, de ambos os sexos, ASA I a III, submetidos a estudo eletrofisiológico intracardíaco eletivo. Foram excluídos os pacientes com doença do nódulo sinoatrial e os portadores de bloqueios cardíacos graves. No laboratório de eletrofisiologia, os pacientes foram inicialmente sedados com midazolam (0,03 mg.kg-1), após 5 minutos (M0) avaliou-se o grau de sedação de intensidade de dor, pressões arteriais sistólica e diastólica, freqüências cardíaca e respiratória e saturação de oxigênio. O eletrofisiologista avaliou as variáveis de condução cardíaca (duração do QRS, intervalos AA, AH, HV e PA), o tempo de recuperação do nódulo sinoatrial e as variáveis de refratariedade cardíaca (período refratário do átrio direito, período refratário do ventrículo direito e período refratário do nódulo atrioventricular). Após as medidas iniciais o remifentanil foi introduzido (bolus de 0,5 μg.kg-1 + infusão de 0,05 μg.kg-1.min-1) e após 20 minutos as mesmas variáveis foram reavaliadas (M1). RESULTADOS: Observou-se diminuição das pressões sistólica e diastólica (p = 0,0001) entre M0 e M1, sem diferença estatística significativa da freqüência respiratória ou da saturação de oxigênio. Houve aumento do intervalo átrio-His (p = 0,006) e do tempo de recuperação do nódulo sinoatrial (p = 0,0004), do período refratário do átrio direito (p = 0,001) e do período refratário do nódulo atrioventricular (p = 0,0001), porém não houve diminuição da freqüência cardíaca basal entre M0 e M1. CONCLUSÕES: O remifentanil alterou as variáveis eletrofisiológicas cardíacas,...

BACKGROUND AND OBJECTIVES: Remifentanil is an opiod with fast onset of action and short acting, and its use in short-duration procedures has increased in the last few years. Bradycardia and asystole are among the side effects reported. The objective of this study was to evaluate the effects of this drug in cardiac conduction and refractory period in human beings. METHODS: A prospective study with 16 patients, ages 18 to 65, both genders, ASA I to III, undergoing elective intracardiac electrophysiological study, was undertaken. Patients with disorders of the sinoatrial node and those with severe cardiac blocks were excluded. In the laboratory of electrophysiology, patients were sedated with midazolam (0.03 mg.kg-1) after 5 minutes the degree of sedation and degree of pain, systolic and diastolic blood pressure, heart rate and respiratory rate, and oxygen saturation were evaluated. The electrophysiologist evaluated cardiac conduction (duration of the QRS complex, and AA, AH, HV, and PA intervals), duration of sinoatrial node recovery, and cardiac refractory period (refractory period of the right atrium, right ventricle, and atrioventricular node). After the initial measurements, remifentanil was administered (bolus of 0.5 μg.kg-1 + infusion of 0.05 μg.kg-1.min-1) and, after 20 minutes, the same parameters were evaluated. RESULTS: There was a reduction in systolic and diastolic blood pressure (p = 0.0001) between M0 and M1, and significant differences in respiratory rate and oxygen saturation, which were not statistically significant. The atrium-His interval (p = 0.006), recovery time of the sinoatrial node (p = 0.0004), refractory period of the right atrium (p = 0.001), and refractory period of the sinoatrial node (p = 0.0001) were all increased; however, there were no differences in heart rate between M0 and M1. CONCLUSIONS: Remifentanil changes cardiac electrophysiological parameters and, in doses higher than the ones used in this study,...

JUSTIFICATIVA Y OBJETIVOS: El remifentanil es un opioide con inicio y fin de acción rápidos, cuyo uso en procedimientos de corta duración se ha venido propagando en los últimos años. Entre los efectos colaterales descritos, hay relatos de bradicardia y asistolia. El objetivo de este estudio fue evaluar los efectos de este fármaco en la conducción y refractariedad cardíaca, en humanos. MÉTODO: Estudio prospectivo de 16 pacientes, entre 18 y 65 años, de ambos sexos, ASA I a III, que se sometieron a estudio electrofisiológico intra cardiaco electivo. Se excluyeron pacientes con enfermedades del nódulo sino-atrial y los portadores de bloqueos cardíacos graves. En el laboratorio de electrofisiologia, los pacientes fueron inicialmente sedados con midazolam (0,03 mg.kg-1), 5 minutos después (M0) se evaluó el grado de sedación e intensidad de dolor, presiones arteriales sistólica y diastólica, frecuencias cardíaca y respiratoria y saturación de oxígeno. El electrofisiologista evaluó las variables de conducción cardíaca (duración del QRS, intervalos AA, AH, HV y PA), el tiempo de recuperación del nódulo sino-atrial y las variables de refractariedad cardíaca (período refractario del atrio derecho, período refractario del ventrículo derecho y período refractario del nódulo atrio ventricular). Después de las medidas iniciales el remifentanil fue introducido (bolo de 0,5 μg.kg-1 + infusión de 0,05 μg.kg-1.min-1) y después de 20 minutos las mismas variables fueron evaluadas nuevamente (M1). RESULTADOS: Se observó disminución de las presiones sistólica y diastólica (p = 0.0001) entre M0 y M1, sin diferencia estadística significativa de la frecuencia respiratoria o de la saturación de oxígeno. Hubo aumento del intervalo atrio-His (p = 0,006) y del tiempo de recuperación del nódulo sino-atrial (p = 0,0004), del período refractario del atrio derecho (p = 0,001) y del período refractario del nódulo atrio ventricular (p = 0,0001), pero no hubo disminución...

Lamin A/C mutations associated with familial and sporadic cases of dilated cardiomyopathy in Koreans

Dilated cardiomyopathy (DCM) is characterized by cardiac dilation and systolic dysfunction. So far sixteen genes have been shown to cause autosomal dominant familial dilated cardiomyopathy (FDC). We identified a large Korean family from the Jeju island showing a clear Mendelian inheritance of FDC. A genomewide linkage scan at 9 cM marker density identified a peak multipoint LOD score of 2.82 at D1S195. Haplotyping of the region with 15 additional markers defined a candidate interval that included a known candidate gene encoding the lamin A/C (LMNA). Sequencing of the LMNA exons revealed one missense mutation at C568T (Arg190Trp) in the alpha-helical rod domain of the LMNA gene cosegregating with FDC with conduction-system disease. The same mutation was found in patients of another Korean family with FDC without conduction-system disease. Upon screening 14 sporadic DCM cases, we found three LMNA mutations including a case having a previously described (Glu161Lys) mutation and two having novel mutations (Glu53Val and Glu186Lys). Our results suggest that variable genotypes of laminopathy are implicated in not only familial but also considerable proportion of sporadic DCM.

Electrical Injury-Induced High-Degree Atrioventricular Block Requiring a Permanent Pacemaker

Electrical injury may lead to a conduction disorder of the heart. We report here on a 36-year-old man, who was treated with a permanent pacemaker, after an electrical injury induced high-degree atrioventricular block and clinical manifestations (dizziness and dyspnea).