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 <

Early Repolarization and Myocardial Scar Predict Poorest Prognosis in Patients with Coronary Artery Disease

PURPOSE: Recent studies show positive association of early repolarization (ER) with the risk of life-threatening arrhythmias in patients with coronary artery disease (CAD). This study was to investigate the relationships of ER with myocardial scarring and prognosis in patients with CAD. MATERIALS AND METHODS: Of 570 consecutive CAD patients, patients with and without ER were assigned to ER group (n=139) and no ER group (n=431), respectively. Myocardial scar was evaluated using cardiac single-photon emission computed tomography. RESULTS: ER group had previous history of myocardial infarction (33% vs. 15%, p<0.001) and lower left ventricular ejection fraction (57+/-13% vs. 62+/-13%, p<0.001) more frequently than no-ER group. While 74 (53%) patients in ER group had myocardial scar, only 121 (28%) patients had in no-ER group (p<0.001). During follow up, 9 (7%) and 4 (0.9%) patients had cardiac events in ER and no-ER group, respectively (p=0.001). All patients with cardiac events had ER in inferior leads and horizontal/descending ST-segment. Patients with both ER in inferior leads and horizontal/descending ST variant and scar had an increased adjusted hazard ratio of cardiac events (hazard ratio 16.0; 95% confidence interval: 4.1 to 55.8; p<0.001). CONCLUSION: ER in inferior leads with a horizontal/descending ST variant was associated with increased risk of cardiac events. These findings suggest that ER in patients with CAD may be related to myocardial scar rather than pure ion channel problem.

The Relationship Between J Wave on the Surface Electrocardiography and Ventricular Fibrillation during Acute Myocardial Infarction

We investigated whether the presence of J wave on the surface electrocardiography (sECG) could be a potential risk factor for ventricular fibrillation (VF) during acute myocardial infarction (AMI). We performed a retrospective study of 317 patients diagnosed with AMI in a single center from 2009 to 2012. Among the enrolled 296 patients, 22 (13.5%) patients were selected as a VF group. The J wave on the sECG was defined as a J point elevation manifested through QRS notching or slurring at least 1 mm above the baseline in at least two leads. We found that the incidence of J wave on the sECG was significantly higher in the VF group. We also confirmed that several conventional risk factors of VF were significantly related to VF during AMI; time delays from the onset of chest pain, blood concentrations of creatine phosphokinase and incidence of ST-segment elevation. Multiple logistic regression analysis demonstrated that the presence of J wave and the presence of a ST-segment elevation were independent predictors of VF during AMI. This study demonstrated that the presence of J wave on the sECG is significantly related to VF during AMI.

Genetic Mutation in Korean Patients of Sudden Cardiac Arrest as a Surrogating Marker of Idiopathic Ventricular Arrhythmia

Mutation or common intronic variants in cardiac ion channel genes have been suggested to be associated with sudden cardiac death caused by idiopathic ventricular tachyarrhythmia. This study aimed to find mutations in cardiac ion channel genes of Korean sudden cardiac arrest patients with structurally normal heart and to verify association between common genetic variation in cardiac ion channel and sudden cardiac arrest by idiopathic ventricular tachyarrhythmia in Koreans. Study participants were Korean survivors of sudden cardiac arrest caused by idiopathic ventricular tachycardia or fibrillation. All coding exons of the SCN5A, KCNQ1, and KCNH2 genes were analyzed by Sanger sequencing. Fifteen survivors of sudden cardiac arrest were included. Three male patients had mutations in SCN5A gene and none in KCNQ1 and KCNH2 genes. Intronic variant (rs2283222) in KCNQ1 gene showed significant association with sudden cardiac arrest (OR 4.05). Four male sudden cardiac arrest survivors had intronic variant (rs11720524) in SCN5A gene. None of female survivors of sudden cardiac arrest had SCN5A gene mutations despite similar frequencies of intronic variants between males and females in 55 normal controls. Common intronic variant in KCNQ1 gene is associated with sudden cardiac arrest caused by idiopathic ventricular tachyarrhythmia in Koreans.

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.

'Hibernating' accessory pathway.

A 13-year-old boy presented with recurrent narrow QRS tachycardia from which he had been suffering for one year. An electrophysiology study revealed a concealed left lateral accessory pathway with inducible orthodromic atrioventricular re-entry tachycardia using the same pathway. The accessory pathway was ablated in January 2004. After the ablation, atrioventricular block was demonstrated (with adenosine), as was ventriculo-atrial block, and the patient had paroxysmal tachycardia one month later. This time, however, the electrocardiogram in sinus rhythm showed a negative delta wave in V1, suggestive of a right-sided accessory pathway. Another electrophysiology study showed no conduction across the left accessory pathway found earlier. The right accessory pathway, which had 'emerged' after the ablation, had an antegrade effective refractory period of 440 msec and a retrograde effective refractory period of <250 msec. Orthodromic atrioventricular re-entry tachycardia using this accessory pathway was easily inducible. The tricuspid annulus was mapped and the second accessory pathway was localized to the right anterolateral region. This was ablated successfully. This is a unique instance of a symptomatic 'hibernating' accessory pathway emerging in adolescence.

[ effect of essence of Citrus aurantium on the electrophysiological properties of isolated perfused rabbit AV-node]

Pharmacological studies and traditional medical literature point to the cardiovascular effects of the Citrus aurantium L. [Rutaceae] in many instances. In the present study, we used isolated perfused AV-node of rabbit as an experimental model to determine the effect of various concentrations of essence of Citrus aurantium [0.1-0.3 v/v] on electrophysiological properties of isolated heart. The second goal of the present study was to assess the protective role of essence of Citrus aurantium on arrhythmogenic effects of ouabain. This was a semi-experimental study. We used isolated perfused rabbit AV-nodal preparation, in three groups. In the first group, the effect of various concentration of the Citrus aurantium [0.1, 0.2, 0.3 ml/l] was assesed on the AV-node. In the second and third groups, the effect of Citrus aurantium was tested in the presence of ouabain [0.1 micro molar] and verapamil [0.1 micro molar]. We used 6 rabbit in each group. Statistical analysis was preformed by SPSS Mean +/- SE was used in the all results. Our results showed depressant effects of extract of Citrus aurantium on Wenchebach Cycle Length [WBCL], AV Conduction Time [AVCT], Effective and Functional Refractory Periods [ERP and FRP]. Rate-dependent properties such as Facilitation and fatigue significantly increased by Citrus.a [0.3ml/l]. We had significant increase in the AVCT [32.6 +/- 3.6 to 40 /- 6.08 msec] and FRP [147 +/- 5.1 to 166.6 +/- 3.6 msec] by Citrus.a. We had a protective role of Citrus aurantium on ouabain induced AV-nodal depression. The magnitude of facilitation and fatigue in the concentration of 0.3 C.aurantium was 7.5 +/- 0.3 and 6.5 +/- 0.5, respectively. The above results indicated potential inhibitory and antiarrhythmic effect of Citrus aurantium in treating supraventricular tachyarrhythmia

Dolor torácico y alteración del segmento ST en pacientes con vías accesorias aurículo-ventriculares: Report of three cases / Chest pain and ST segment abnormalities in patients with accessory atrioventricular pathways

We report three patients with pre-excitation syndrome that resembled an acute coronary syndrome. A 65 years old woman, consulting in the emergency room for palpitations and retrosternal pain. EKG showed regular tachycardia and ST depression that reverted spontaneously after an episode of vomiting. A subsequent EKG demonstrated a pre-excitation syndrome and the accessory pathway was fulgurated. A 18 years old male presenting with tachycardia and chest pain elicited during exercise. An EKG showed a pre-excitation syndrome and ST segment elevation in V2 and V3. A coronary angiogram was normal. The accessory pathway successfully fulgurated. A 63 years old woman that presented tachycardia while exercising. She was subjected to an electrical cardioversion. An electrophysiological study showed an accessory pathway that was successfully fulgurated.

Mecanismos básicos das arritmias: o que o clínico precisa saber? / Basic mechanisms of arrhythmia: what physicians should know?

O manuseio clínico das arritmias cardíacas sofreu profundas modificações durante a última década. Atualmente, parcela significativa de pacientes acometidos por taquiarritmias supraventriculares e ventriculares pode ser curada por meio da ablação por cateter. Houve também progressos notáveis na prevenção da morte súbita arrítmica em populações de risco com o advento dos desfibriladores automáticos implantáveis. Além disso, novos fármacos vêm sendo desenvolvidos, buscando controlar os distúrbios do ritmo de maneira eficaz e segura. Com freqüência cada vez maior, o clínico se depara com a necessidade de indicar e interpretar os resultados de um estudo eletrofisiológico, além de avaliar e tratar pacientes com arritmias complexas e/ou desfibriladores implantáveis. A utilização clínica racional desse amplo arsenal diagnóstico e terapêutico pode ser muito facilitada pelo entendimento dos mecanismos fundamentais das arritmias cardíacas. Este artigo descreve sucintamente os mecanismos básicos das arritmias cardíacas, com ênfase em seus aspectos relevantes à prática clínica.

Coronary sinus diverticulum with a concealed posteroseptal accessory pathway: a red herring?

A 21-year-old male presented with episodes of paroxysmal tachycardia mediated via a concealed posteroseptal accessory pathway. He was also found to have a diverticulum of the coronary sinus. However, successful radiofrequency ablation was achieved only endocardially under the mitral annulus and not within the diverticulum.

Ablación con radiofrecuencia de una vía accesoria lateral izquierda durante fibrilación auricular pre-excitada / Localization and radiofrequency catheter ablation of left-sided accessory pathway during atrial fibrillation

La fibrilación durante un estudio electrofisiológico en pacientes con síndrome de Wolff-Parkinson-White es un problema relativamente frecuente que requiere en muchas ocasiones, de la administración de antiarrítmicos o cardioversión eléctrica, prolongando el tiempo del procedimiento. El propósito de este reporte es demostrar que es factible el mapeo y la ablación de una vía accesoria manifiesta durante fibrilación auricular y que así se puede acortar la duración del estudio. Durante el estudio electrofisiológico del paciente desapareció la pre-excitación y espontáneamente o por la manipulación de los catéteres, presentó fibrilación auricular pre-excitada. Decidimos realizar el mapeo de la vía durante esta arritmia porque mostraba máxima pre-excitación y pensamos que esto pudiera facilitar el registro del potencial de Kent y el sitio de éxito de la ablación. Con el catéter de ablación en la posición lateral izquierda y subvalvular se obtuvo un electrograma ventricular precoz y una deflexión rápido previa a la actrivación ventricular que corresponde al potencial del haz de Kent y que no observamos durante latidos no pre-excitados. Al aplicar la radiofrecuencia con control de temperatura al 70ºC, se eliminó la conducción anterógrada de la vía en los primeros tres segundos y continuamos la radiofrecuencia durante 2 minutos. El tiempo del procedimiento fue de 60 minutos. Concluimos que realizar el mapeo y ablación de una vía accesoria manifiesta durante fibrilación auricular es posible y que además de acortar la duración del procedimiento de ablación puede evitar cardioversiones eléctricas repetidas

Anaesthetic management of patients undergoing surgery for tachyarrhythmias. Initial experience with 16 patients.

Sixteen patients suffering from various cardiac arrhythmias were treated surgically. Intraoperative computerised electrophysiologic mapping was used in 14. Thirteen patients were suffering from Wolff-Parkinson-White syndrome. They underwent surgical division or cryoablation of accessory pathways. Two patients who had rheumatic mitral stenosis with left atrial clot underwent "Maze III" procedure with open mitral commissurotomy and clot removal. One patient with paroxysmal refractory ventricular tachycardia and a left ventricular aneurysm had an aneurysmectomy with subendocardial resection of the arrhythmic focus. All antiarrhythmic medications were discontinued preoperatively. Morphine was the principal anaesthetic agent, supplemented with halothane. Muscle relaxation was provided with pancuronium bromide. The various problems encountered included hypotension and arrhythmia during placement of epicardial band array for mapping (4 patients), ventricular tachycardia during internal jugular vein cannulation (1 patient) and continuance of delta wave after cryoablation in 2 patients. Halothane may have interfered with electrophysiologic mapping and accurate localization of accessory pathway leading to persistence of delta wave. The choice of anaesthetic agents should be guided by the electrophysiologic effects and potential influence of these agents on the accessory pathways.

Ablaçäo por radiofrequência de taquicardia supraventricular incessante por via anômala de conduçäo retrógrada decremental / Radiofrequency Ablation of Incessant Supraventricular Tachycardia Due to Decremental Retrograde Conduction Via Anomalous Pathways

Woman, 46 years-old with incessant supraventricular tachycardia and tachycardiomyopathy. The diagnosis of a concealed retrograde long conduction time accessory pathway was obtained with the delay of the next atrial activation by delivering a ventricular premature beat during His bundle refratoriness. During electrophysiologic investigation the earliest atrial activation was found to be within the coronary sinus ostium. Two 25 watts applications of radiofrequency were followed by the interruption of the incessant supraventricular tachycardia. The patient has remained symptom free without recurrence for 60 days. Radiofrequency was effective for the treatment of this tachycardia

Hipomagnesemia y su relación con trastornos del ritmo cardíaco

La infusión de sales de magnesio ha sido eficaz para la supresión de algunos trastornos del ritmo cardíaco, por lo cual se ha involucrado la hipomagnesemia en la génesis de los mismos. Nosotros investigamosla presencia de arritmias cardíacas recurrentes y sostenidas en un grupo de 27 pacientes sometidos a cirugía cardíaca bajo circulación extracorpórea, modelo clínico óptimo para producir hipomagnesemia. Aunque observamos una disminución significativa en la concentración sérica del ion, incluso hasta las 48 horas del postoperatorio, en ningún caso encontramos trastornos del ritmo atribuibles a este estado. El efecto anticálcico del magnesio puede ser responsable de manera indirecta del supuesto efecto antiarrítmico de este catión

Marcapaso cardíaco permanente: indicaciones clínicas, electrocardiográficas y seguimiento en 112 pacientes

En 112 pacientes que requirieron la implantación de un marcapaso cardíaco permanente (MCP), se determinan las indicaciones clínicas, electrocardiográficas (ECG), las posibles causas de los trastornos del ritmo y de la conducción y se realiza un seguimiento para describir los principales factores del mal funcionamiento del marcapaso (MFM), el estado sintomático post-implantación y las causas de mortalidad en estos pacientes. La edad promedio fue de 68 años. Los síntomas previos a la implantación del MCP fueron síncope y mareos. Las indicaciones por ECG: Bloqueo AV completo, síndrome del seno enfermo, bloqueo AV de segundo grado tipo Mobitz II y bloqueo bifascicular sintomático. No se encontró una causa específica de la alteración del ritmo en el 66 por ciento y fue de origen isquemico en el 28 por ciento de los pacientes. Durante el seguimiento los problemas de MFM fueron el desplazamiento del electrodo y la infección del bolsillo, en la mayoría hubo mejoría de los síntomas y la muerte súbita fue la principal causa de mortalidad en 7 de 8 pacientes

Infarto do miocárdio e lesäo coronária em paciente portador de atresia pulmonar / Myocardial infarction and coronary lesion in a patient with pulmonary atresia

Os autores descrevem um caso de proliferaçäo fibro-elástica oclusiva de um segmento proximal da artéria descendente posterior em criança com um mês de idade. Esta alteraçäo arterial, juntamente com a atresia da valva pulmonar, hipoplasia do ventrículo direito e episódio de anóxia neonatal, determinaram infartos do miocárdio confluentes e progressivos que levaram o paciente a óbito

Conexión atrioventricular cruzada con cabalgamiento de la válvula atrioventricular derecha / Crossed atrioventricular connection with stradding of the right atrioventricular valve

Se describe un caso de conexión atrioventricular cruzada (o "Criss-Cross") en situs inversus, conexión atrioventricular concordante, conexión ventrículo arterial tipo doble vía de salida del ventrículo derecho y cabalgamiento de la válvula atrioventricular derecha. Se hace una revisión de la literatura y se analizan las características angiográficas de esta malformación, destacando la importancia de la angiografía selectiva para conocer las conexiones atrioventriculares y ventrículo arteriales en forma precisa, y la presentación de varias lesiones raras asociadas en el mismo caso. Se comenta la utilidad del ecocardiograma para el diagnóstico de las malformaciones asociadas