Fisiopatología del bloqueo interauricular y su rol como predictor de arritmias supraventriculares

El Bloqueo Interauricular (BIA) puede servir como un valioso marcador electrocardiográfico para evaluar el riesgo del desarrollo de arritmias auriculares, y nueva aparición de fibrilación auricular (FA). El BIA se produce por un deterioro en la conducción auricular que implica un retraso en la conducción del estímulo eléctrico desde la aurícula derecha a la aurícula izquierda. Las causas probables de interrupción del haz de Bachmann incluyen isquemia, enfermedad degenerativa del envejecimiento, enfermedades infiltrativas, enfermedad coronaria difusa y afecciones inflamatorias. Los factores de riesgo para el BIA avanzado, la fibrilación auricular (FA) y el accidente cerebrovascular (ACV) parecen ser muy similares, y la patogénesis subyacente probablemente se deba a fibrosis miocárdica y remodelación auricular. El bloqueo interauricular se relaciona clínicamente a la aparición de taquiarritmias supraventriculares y está relacionado al remodelamiento auricular. Aunque el agrandamiento auricular y el BIA comparten un patrón electrocardiográfico similar, son dos entidades separadas. Sin embargo, muchos autores aún asocian una duración de la onda P mayor a 120 ms con agrandamiento de la aurícula izquierda. El remodelamiento auricular modifica la velocidad de conducción, la arquitectura cardiaca, los canales iónicos dependientes de voltaje, y los componentes de resistencia y capacitancia, como son el espacio extracelular y las uniones celulares. La alteración de estas propiedades afecta las propiedades electrofisiológicas de la conducción auricular y favorece el BIA, los trastornos auriculares y la génesis de FA.

Interatrial block (IAB) can serve as a valuable electrocardiographic marker to assess the risk of developing atrial arrhythmias, and new onset of atrial fibrillation (AF). The IAB is produced by a deterioration in atrial conduction that implies a delay in the conduction of the electrical stimulus from the right atrium to the left atrium. Probable causes of Bachmann bundle interruption include ischemia, degenerative disease of aging, infiltrative diseases, diffuse coronary disease, and inflammatory conditions. The risk factors for advanced IAB, atrial fibrillation (AF), and cerebrovascular accident (CVA) appear to be very similar, and the underlying pathogenesis is probably due to myocardial fibrosis, and atrial remodeling. The interatrial block is clinically related to the appearance of supraventricular tachyarrhythmias and is related to atrial remodeling. Although atrial enlargement and IAB share a similar electrocardiographic pattern, they are separate entities. However, many authors still associate P wave duration greater than 120 ms with left atrial enlargement. Atrial remodeling modifies conduction velocity, cardiac architecture, voltage-gated ion channels, and resistance and capacitance components, such as the extracellular space and cell junctions. The alteration of these properties affects the electrophysiological properties of atrial conduction and favors IAB, atrial disorders, and the genesis of AF.

Value of advanced interatrial block in the diagnosis of the ischemic stroke's aetiology: A cohort study

Introduction and objectives: Advanced interatrial block has been linked with atrial fibrillation (AF) (Bayes syndrome). On the other hand, the aetiology of the stroke remains unknown in approximately 20–25% of patients admitted due to ischaemic stroke. The aim of this study was to evaluate whether advanced interatrial block and CHADS2-VASC scale is linked to AF in patients admitted due to ischaemic stroke without previous AF history.MethodsA prospective analysis of consecutive in-hospital patients admitted with ischemic stroke between January/2018 and April/2019 in a stroke hospital was performed. Patients had to be in sinus rhythm at admission and without previous history of AF/atrial flutter. During follow up patients receive the usual care.ResultsA total of 236 patients were included. The median follow-up was 540 days (407–695). 19 patients (8.1%) had advanced interatrial block at admission. Advanced interatrial block was associated with the diagnosis of AF during follow up (5 (26.3%) Vs 21 (9.7%) p=0.027). A CHADS2-VASC score>4 at admission was also associated with AF diagnosis during follow up (23(14.6%) vs 3(3.9%) p=0.009).ConclusionThis study confirms the association of advanced interatrial block and CHADS2-VASC>4 at admission with the diagnosis of AF during follow up in patients with ischemic stroke. This association could have important implications in patients with ischemic stroke who present advanced interatrial block and without previous history of AF. (AU)

Introducción y objetivos: El bloqueo interauricular (BIA) completo se relaciona con el desarrollo de arritmias supraventriculares, especialmente de fibrilación auricular (FA) (síndrome de Bayés). En este trabajo evaluamos la utilidad de este fenómeno para discernir la etiología cardioembólica en los pacientes ingresados por ictus isquémico. También se estudió la relación entre la puntuación en la escala CHADS 2-VA 2 Sc y el desarrollo de FA durante el seguimiento.MétodosAnálisis prospectivo de pacientes consecutivos ingresados por ictus isquémico entre enero del 2018 y abril del 2019 en un hospital terciario centro de referencia de ictus. Los pacientes incluidos debían de estar en ritmo sinusal en el momento del ingreso y no tener historia previa de FA/flutter auricular. Se realizó el seguimiento mediante las consultas y estudios de rutina, sin intervenir en su manejo habitual.ResultadosSe incluyó a 236 pacientes. La mediana de seguimiento fue de 540 días (407-695); 19 pacientes (8,1%) presentaron BIA en el electrocardiograma al ingreso. El BIA completo al ingreso se relacionó con el desarrollo posterior de FA (5 [26,3%) vs. 21 [9,7%]; p=0,027). También se observó que un CHADS 2-VA 2 Sc>4 al ingreso se relacionaba con presentar FA durante el seguimiento (23 [14,6%] vs. 3 [3,9%]; p=0,009).ConclusiónCon este estudio se demuestra por primera vez en pacientes con ictus isquémico que tanto el BIA completo como un CHADS 2-VA 2 Sc>4 se asocian con el desarrollo de FA en el seguimiento. Esta asociación puede tener importantes implicaciones prácticas en el manejo de pacientes ingresados por ictus que presenten BIA completo. (AU)

Dilatación de la aurícula izquierda en deportistas de alta competición y electrofisiología auricular / Left atrial enlargement in competitive athletes and atrial electrophysiology

Introducción y objetivos: Existe poca información sobre la dilatación de la aurícula izquierda (AI) y los parámetros electrocardiográficos en deportistas. Métodos: Estudio observacional multicéntrico en deportistas de competición y controles. La dilatación de la AI se definió como un volumen indexado por área de superficie corporal ≥ 34ml/m2. Se estudió su relación con parámetros electrocardiográficos auriculares. Resultados: Se incluyó en total a 356 sujetos: 308 deportistas de competición (media de edad, 36,4±11,6 años) y 48 controles (49,3±16,1 años). Los deportistas de competición tenían un mayor volumen medio indexado de la AI (29,8±8,6 frente a 25,6±8,0ml/m2; p=0,006) y una mayor prevalencia de dilatación de la AI (113 [36,7%] frente a 5 [10,4%]; p <0,001), sin diferencias relevantes en cuanto a la duración de la onda P (106,3±12,5 frente a 108,2±7,7 ms; p=0,31), la prevalencia de bloqueo interauricular (40 [13,0%] frente a 4 [8,3%]; p=0,36) ni la puntuación Morphology-Voltage-P-wave duration (1,8±0,84 frente a 1,5±0,8; p=0,71). El entrenamiento competitivo se asoció de manera independiente con la dilatación de la AI (OR=14,7; IC95%, 4,7-44,0; p < 0,001), pero no con la duración de la onda P (OR=1,02; IC95%, 0,99-1,04), el bloqueo interauricular (OR=1,4; IC95%, 0,7-3,1) o la puntuación Morphology-Voltage-P-wave duration (OR=1,4; IC95%, 0,9-2,2). Conclusiones: La dilatación de la AI es frecuente en deportistas de competición, pero no se acompaña de una modificación relevante en los parámetros electrocardiográficos (AU)

Introduction and objectives: There are scarce data on left atrial (LA) enlargement and electrophysiological features in athletes. Methods: Multicenter observational study in competitive athletes and controls. LA enlargement was defined as LA volume indexed to body surface area ≥ 34mL/m2. We analyzed its relationship with atrial electrocardiography parameters. Results: We included 356 participants, 308 athletes (mean age: 36.4±11.6 years) and 48 controls (mean age: 49.3±16.1 years). Compared with controls, athletes had a higher mean LA volume index (29.8±8.6 vs 25.6±8.0mL/m2, P=.006) and a higher prevalence of LA enlargement (113 [36.7%] vs 5 [10.4%], P <.001), but there were no relevant differences in P-wave duration (106.3±12.5ms vs 108.2±7.7ms; P=.31), the prevalence of interatrial block (40 [13.0%] vs 4 [8.3%]; P=.36), or morphology-voltage-P-wave duration score (1.8±0.84 vs 1.5±0.8; P=.71). Competitive training was independently associated with LA enlargement (OR, 14.7; 95%CI, 4.7-44.0; P <.001) but not with P-wave duration (OR, 1.02; 95%CI, 0.99-1.04), IAB (OR, 1.4; 95%CI, 0.7-3.1), or with morphology-voltage-P-wave duration score (OR, 1.4; 95%CI, 0.9-2.2). Conclusions: LA enlargement is common in adult competitive athletes but is not accompanied by a significant modification in electrocardiographic parameters (AU)

Value of advanced interatrial block in the diagnosis of the ischemic stroke's aetiology: A cohort study.

INTRODUCTION AND OBJECTIVES: Advanced interatrial block has been linked with atrial fibrillation (AF) (Bayes syndrome). On the other hand, the aetiology of the stroke remains unknown in approximately 20-25% of patients admitted due to ischaemic stroke. The aim of this study was to evaluate whether advanced interatrial block and CHADS2-VASC scale is linked to AF in patients admitted due to ischaemic stroke without previous AF history. METHODS: A prospective analysis of consecutive in-hospital patients admitted with ischemic stroke between January/2018 and April/2019 in a stroke hospital was performed. Patients had to be in sinus rhythm at admission and without previous history of AF/atrial flutter. During follow up patients receive the usual care. RESULTS: A total of 236 patients were included. The median follow-up was 540 days (407-695). 19 patients (8.1%) had advanced interatrial block at admission. Advanced interatrial block was associated with the diagnosis of AF during follow up (5 (26.3%) Vs 21 (9.7%) p=0.027). A CHADS2-VASC score>4 at admission was also associated with AF diagnosis during follow up (23(14.6%) vs 3(3.9%) p=0.009). CONCLUSION: This study confirms the association of advanced interatrial block and CHADS2-VASC>4 at admission with the diagnosis of AF during follow up in patients with ischemic stroke. This association could have important implications in patients with ischemic stroke who present advanced interatrial block and without previous history of AF.

Left atrial enlargement in competitive athletes and atrial electrophysiology.

INTRODUCTION AND OBJECTIVES: There are scarce data on left atrial (LA) enlargement and electrophysiological features in athletes. METHODS: Multicenter observational study in competitive athletes and controls. LA enlargement was defined as LA volume indexed to body surface area ≥ 34mL/m2. We analyzed its relationship with atrial electrocardiography parameters. RESULTS: We included 356 participants, 308 athletes (mean age: 36.4±11.6 years) and 48 controls (mean age: 49.3±16.1 years). Compared with controls, athletes had a higher mean LA volume index (29.8±8.6 vs 25.6±8.0mL/m2, P=.006) and a higher prevalence of LA enlargement (113 [36.7%] vs 5 [10.4%], P <.001), but there were no relevant differences in P-wave duration (106.3±12.5ms vs 108.2±7.7ms; P=.31), the prevalence of interatrial block (40 [13.0%] vs 4 [8.3%]; P=.36), or morphology-voltage-P-wave duration score (1.8±0.84 vs 1.5±0.8; P=.71). Competitive training was independently associated with LA enlargement (OR, 14.7; 95%CI, 4.7-44.0; P <.001) but not with P-wave duration (OR, 1.02; 95%CI, 0.99-1.04), IAB (OR, 1.4; 95%CI, 0.7-3.1), or with morphology-voltage-P-wave duration score (OR, 1.4; 95%CI, 0.9-2.2). CONCLUSIONS: LA enlargement is common in adult competitive athletes but is not accompanied by a significant modification in electrocardiographic parameters.

Rol del bloqueo interauricular avanzado en la predicción de accidentes cerebrovasculares isquémicos

RESUMEN El bloqueo interauricular (BIA) es un marcador significativo en la predicción del desarrollo de Fibrilación Auricular (FA). El sustrato histopatológico que se observa en el proceso de remodelación auricular es la fibrosis del miocardio auricular induciendo disincronía interauricular. La disfunción electromecánica de la aurícula izquierda (AI) produce una activación anormal de sus paredes, el aumento de la presión, la dilatación, la disfunción endotelial, y la fibrosis de la AI. Estas alteraciones favorecen la conducción lenta, el bloqueo unidireccional y el desarrollo de mecanismos de reentrada con la aparición de la FA con sus nefastas complicaciones, entre ellas el accidente cerebrovascular (ACV). El BIA está presente hasta en un 59% de los pacientes mayores de la población general y se asoció con un aumento del riesgo de unas 3 veces más de FA de nueva aparición y ACV isquémico. Es evidente el interés académico, clínico, y terapéutico en el diagnóstico electrocardiográfico certero del BIA avanzado, ya que el mismo se asocia con arritmias supraventriculares, fibrilación auricular, ACV embólicos y mortalidad. La detección de BIA avanzado en pacientes con ACV isquémico previo permite identificar a pacientes de alto riesgo de recurrencia en los que algunas terapias farmacológicas podrían ser beneficiosas. Los pacientes con BIA avanzado sin episodios previos de FA documentada también presentan un riesgo aumentado de ACV embólico. Por lo tanto, es necesario realizar ensayos clínicos randomizados cuyos resultados podrían avalar el uso de anticoagulantes en ausencia de FA documentada en pacientes con BIA avanzado.

ABSTRACT Interatrial block (IAB) is a significant marker in the prediction of the development of Atrial Fibrillation (AF). The histopathological substrate observed in the atrial remodeling process is fibrosis of the atrial myocardium, inducing interatrial desynchrony. Electromechanical dysfunction of the left atrium (LA) produces abnormal activation of its walls, increased pressure, dilation, endothelial dysfunction, and fibrosis of the LA. These alterations favor slow conduction, unidirectional block and the development of reentry mechanisms with the appearance of AF with its disastrous complications, including cerebrovascular accident (CVA). IAB is present in up to 59% of older patients in the general population and was associated with a 3-fold increased risk of new-onset AF and ischemic stroke. The academic, clinical, and therapeutic interest in the accurate electrocardiographic diagnosis of advanced IAB is evident, since it is associated with supraventricular arrhythmias, atrial fibrillation, embolic stroke and mortality. The detection of advanced IAB in patients with previous ischemic stroke allows the identification of patients at high risk of recurrence in which some pharmacological therapies could be beneficial. Patients with advanced IAB with no prior documented AF episodes are also at increased risk of embolic stroke. Therefore, it is necessary to conduct randomized clinical trials whose results might be available in the use of anticoagulants in the absence of documented AF in patients with advanced IAB.

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

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

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

Differential characteristics of the typical and atypical advanced interatrial block.

Objetivo: Se denomina bloqueo interauricular avanzado (BIA) a la existencia de una onda P ≥ 120 ms y bifásica +/- en las derivaciones inferiores (II-III-VF) del electrocardiograma (ECG) de superficie, el cual constituye un factor predictivo significativo del desarrollo de fibrilación auricular. En fecha reciente se han descrito cuatro patrones de BIA atípicos (BIA-At) con base en la morfología y la duración de la onda P, sin conocer si comparten patogenia y características clínicas similares. Método: Estudio observacional, descriptivo y retrospectivo de pacientes, visitados en el Servicio de Cardiología, en ritmo sinusal y con BIA. Las variables analizadas se obtuvieron de la historia clínica informatizada. El análisis de la onda P se efectuó al aumentar el tamaño del electrocardiograma y mediante calipers electrónicos. El análisis estadístico se realizó con SPSS 19.0, con nivel de significación de p < 0.05. Resultados: Se incluyó a 75 pacientes con media de edad de 74.4 ± 11.7 años, con 62.7% de varones. Se compararon los grupos de pacientes con BIA típico (BIA-T) y BIA-At. El primero se relacionó con la existencia de diabetes mellitus (p = 0.001), enfermedad renal crónica estadio ≥ 3 (p = 0.036), bloqueo auriculoventricular (p = 0.006) y una menor fracción de expulsión ventricular media (p = 0.025); no hubo diferencias respecto de la prevalencia de fibrilación auricular/flúter o accidente cerebrovascular. Sólo la diabetes se acompañó de riesgo de ser un BIA-T (OR: 6.4; p = 0.002; IC 95%: 2.0-21.1). Conclusiones: La diabetes mellitus constituye el único factor de riesgo de que un BIA sea típico. Los pacientes con BIA-T y BIA-At presentan similar prevalencia de fibrilación auricular y accidente cerebrovascular, por lo que son objeto de un mismo tratamiento clínico. Objective: It is called advanced interatrial block (IAB) to the existence of a P wave ≥ 120 ms and biphasic ± in the lower leads II-III-VF of the surface electrocardiogram (ECG), which constitutes a significant predictive factor for the development of atrial fibrillation. Recently, four patterns of atypical aIAB (At-IAB) have been described based on the morphology and duration of the P wave, but it's unknown if they share the same pathogenesis and clinical characteristics. Method: An observational, descriptive and retrospective study was performed with patients, visited in cardiology, who have a sinus rhythm and with aIAB. The analyzed variables were obtained from the computerized clinical history. The analysis of the P wave was made by increasing the size of the ECG and by electronic calipers. Statistical analysis was performed with SPSS 19.0; level of significance: p < 0.05. Results: A total of 75 patients with an average age of 74.4 ± 11.7 years and with a 62.7% males, were included. It was compared the group of patients with typical aIAB (T-aIAB) and with At-aIAB. The first one was associated with the existence of diabetes mellitus (p = 0.001), chronic kidney disease stage ≥ 3 (p = 0.036), atrioventricular block (p = 0.006) and a lower mean ventricular ejection fraction (p = 0.025); there were no differences regarding the prevalence of atrial fibrillation/flutter or stroke. Only diabetes was associated with the risk of T-aIAB (odds ratio: 6.4; p = 0.002; 95% confidence interval: 2.0-21.1). Conclusions: Diabetes mellitus is the only risk factor for an aIAB to be typical. Patients with T-aIAB and At-aIAB have a similar prevalence of atrial fibrillation and stroke, so they must follow the same clinical management.

Características diferenciales del bloqueo interauricular avanzado típico y atípico / Differential characteristics of the typical and atypical advanced interatrial block

Resumen Objetivo: Se denomina bloqueo interauricular avanzado (BIA) a la existencia de una onda P ≥ 120 ms y bifásica +/- en las derivaciones inferiores (II-III-VF) del electrocardiograma (ECG) de superficie, el cual constituye un factor predictivo significativo del desarrollo de fibrilación auricular. En fecha reciente se han descrito cuatro patrones de BIA atípicos (BIA-At) con base en la morfología y la duración de la onda P, sin conocer si comparten patogenia y características clínicas similares. Método: Estudio observacional, descriptivo y retrospectivo de pacientes, visitados en el Servicio de Cardiología, en ritmo sinusal y con BIA. Las variables analizadas se obtuvieron de la historia clínica informatizada. El análisis de la onda P se efectuó al aumentar el tamaño del electrocardiograma y mediante calipers electrónicos. El análisis estadístico se realizó con SPSS 19.0, con nivel de significación de p < 0.05. Resultados: Se incluyó a 75 pacientes con media de edad de 74.4 ± 11.7 años, con 62.7% de varones. Se compararon los grupos de pacientes con BIA típico (BIA-T) y BIA-At. El primero se relacionó con la existencia de diabetes mellitus (p = 0.001), enfermedad renal crónica estadio ≥ 3 (p = 0.036), bloqueo auriculoventricular (p = 0.006) y una menor fracción de expulsión ventricular media (p = 0.025); no hubo diferencias respecto de la prevalencia de fibrilación auricular/flúter o accidente cerebrovascular. Sólo la diabetes se acompañó de riesgo de ser un BIA-T (OR: 6.4; p = 0.002; IC 95%: 2.0-21.1). Conclusiones: La diabetes mellitus constituye el único factor de riesgo de que un BIA sea típico. Los pacientes con BIA-T y BIA-At presentan similar prevalencia de fibrilación auricular y accidente cerebrovascular, por lo que son objeto de un mismo tratamiento clínico.

Abstract Objective: It is called advanced interatrial block (IAB) to the existence of a P wave ≥ 120 ms and biphasic ± in the lower leads II-III-VF of the surface electrocardiogram (ECG), which constitutes a significant predictive factor for the development of atrial fibrillation. Recently, four patterns of atypical aIAB (At-IAB) have been described based on the morphology and duration of the P wave, but it’s unknown if they share the same pathogenesis and clinical characteristics. Method: An observational, descriptive and retrospective study was performed with patients, visited in cardiology, who have a sinus rhythm and with aIAB. The analyzed variables were obtained from the computerized clinical history. The analysis of the P wave was made by increasing the size of the ECG and by electronic calipers. Statistical analysis was performed with SPSS 19.0; level of significance: p < 0.05. Results: A total of 75 patients with an average age of 74.4 ± 11.7 years and with a 62.7% males, were included. It was compared the group of patients with typical aIAB (T-aIAB) and with At-aIAB. The first one was associated with the existence of diabetes mellitus (p = 0.001), chronic kidney disease stage ≥ 3 (p = 0.036), atrioventricular block (p = 0.006) and a lower mean ventricular ejection fraction (p = 0.025); there were no differences regarding the prevalence of atrial fibrillation/flutter or stroke. Only diabetes was associated with the risk of T-aIAB (odds ratio: 6.4; p = 0.002; 95% confidence interval: 2.0-21.1). Conclusions: Diabetes mellitus is the only risk factor for an aIAB to be typical. Patients with T-aIAB and At-aIAB have a similar prevalence of atrial fibrillation and stroke, so they must follow the same clinical management.

Bloqueo interauricular avanzado en pacientes con hipertensión arterial sistémica y fibrilación auricular / Advanced interatrial block in patients with systemic arterial hypertension and atrial fibrillation

La hipertensión arterial sistémica (HTA) continúa siendo un factor de riesgo de indudable importancia en el proceso del desarrollo de la enfermedad cardiovascular y la fibrilación auricular (FA). La FA constituye la arritmia sostenida más frecuentemente detectada. Es primordial dar el énfasis necesario a la prevención y al diagnóstico precoz de enfermedades con gran impacto social, médico y económico a la salud pública. En este contexto, es importante detectar la enfermedad en estadio subclínico e identificar factores que determinen con gran confiabilidad la aparición y desarrollo de una enfermedad. El electrocardiograma (ECG) es un método auxiliar de diagnóstico seguro, económico, de fácil manejo y accesible en prácticamente todos los centros médicos, y que nos sirve para detectar diversas entidades nosológicas. El bloqueo interauricular (BIA) diagnosticado por el ECG ocurre debido a un enlentecimiento de conducción entre las aurículas derecha e izquierda a causa de un retardo en la conducción de impulsos a través del haz de Bachmann. El sustrato anatómico para BIA está producido por la remodelación auricular debido a fibrosis, induciendo disincronía interauricular. El BIA está presente hasta en un 59% de los pacientes mayores de la población general y estuvo directamente asociado a la HTA y la FA. Además, el BIA avanzado se asoció con un aumento del riesgo de unas 3 veces más de FA de nueva aparición y accidente cerebrovascular isquémico. Por lo tanto, es imprescindible realizar una investigación prospectiva adicional para determinar las estrategias óptimas en el adecuado manejo terapéutico de estos pacientes

Systemic arterial hypertension (AHT) continues to be a risk factor of undoubted importance in the process of development of cardiovascular disease and atrial fibrillation (AF). AF is the most frequently detected sustained arrhythmia. For this reason, it is essential to give the necessary emphasis to the prevention and early diagnosis of diseases with great social, medical and economic impact on public health. In this context, it is important to detect the subclinical stage disease and identify factors that determine with great reliability the appearance and development of a disease. The electrocardiogram (ECG) is a safe, inexpensive auxiliary diagnostic method, easy to use and accessible in practically all medical centers, and which serves to detect various nosological entities. The interatrial block (IAB) diagnosed by the ECG occurs due to a slowing down of conduction between the right and left atria due to a delay in the conduction of impulses through the Bachmann pathway. The anatomical substrate for IAB is produced by atrial remodeling due to fibrosis, inducing interatrial dyssynchrony. IAB is present in up to 59% of older patients in the general population and was directly associated with AHT and AF. In addition, advanced IAB was associated with a 3-fold increased risk of new-onset AF and ischemic stroke. Therefore, it is essential to carry out additional prospective research to determine the optimal strategies in the adequate therapeutic management of these patients

What every clinician should know about Bayés syndrome.

Bayés syndrome is a new clinical entity, characterized by the association of advanced interatrial block (IAB) on surface electrocardiogram with atrial fibrillation (AF) and other atrial arrhythmias. This syndrome is associated with an increased risk of stroke, dementia, and mortality. Advanced IAB is diagnosed by the presence of a P-wave ≥ 120ms with biphasic morphology (±) in inferior leads. The cause of IAB is complete Bachmann bundle blockade, leading to retrograde depolarization of the left atrium from areas near the atrioventricular junction. The anatomic substrate of advanced IAB is fibrotic atrial cardiomyopathy. Dyssynchrony induced by advanced IAB is a trigger and maintenance mechanism of AF. This alteration of the atrial architecture produces atrial remodeling, blood stasis and hypercoagulability, triggering the thrombogenic cascade. The presence of advanced IAB, even in patients without documented atrial arrhythmias, has also been associated with AF, stroke, dementia, and mortality. However, in these patients, there is no evidence to support the use of anticoagulation. Therefore, in patients with advanced IAB, a proactive search for AF is recommended.

[Bayes' syndrome in cardiac surgery: prevalence of interatrial block in patients younger than 65 years undergoing cardiac surgery and association with postoperative atrial fibrillation]. / Síndrome de Bayés en cirugía cardiaca: prevalencia de bloqueo interauricular en menores de 65 años sometidos a cirugía cardiaca y su asociación con fibrilación auricular en el postoperatorio.

OBJECTIVE: Interatrial block (IAB) is a well-known entity that is associated with an increased risk of atrial fibrillation (AF). This association is called Bayes' syndrome. The aim of our study was to define the prevalence of IAB among patients younger than 65 years undergoing cardiac surgery and determine whether there is an association between the presence of interatrial conduction delay and postoperative atrial fibrillation (POAF). METHOD: A total of 207 patients were enrolled. Partial IAB was defined as P-wave>120ms. Advanced IAB was defined as P-wave>120ms+biphasic morphology in the inferior leads. Ocurrence of POAF was assessed and a comparative analysis was conducted between patients that did and did not develop AF. RESULTS: IAB prevalence was 78.3% (partial 66.2%, advanced 12.1%). POAF occurred in 28.5% of all patients, and was more frequent among patients with advanced IAB (44%) compared to 27.7% and 24.4% of POAF among patients with partial IAB and without IAB, respectively. Patients who developed POAF were significantly older, had significantly higher NTproBNP, higher prevalence of atrial enlargement and thyroid disease. After multivariate analysis, advanced IAB was found to be independently associated with POAF. CONCLUSIONS: IAB is a frequent finding among patients undergoing cardiac surgery. According to our results, advanced IAB is independently associated with POAF in younger patients (<65 years) undergoing cardiac surgery.

Síndrome de Bayés en cirugía cardiaca: prevalencia de bloqueo interauricular en menores de 65 años sometidos a cirugía cardiaca y su asociación con fibrilación auricular en el postoperatorio / Bayes' syndrome in cardiac surgery: prevalence of interatrial block in patients younger than 65 years undergoing cardiac surgery and association with postoperative atrial fibrillation

Resumen Objetivo: El bloqueo interauricular (BIA) es una entidad asociada con un mayor riesgo de presentar fibrilación auricular (FA), constituyendo el denominado síndrome de Bayés. El objetivo de nuestro estudio fue definir la prevalencia de BIA en pacientes menores de 65 años sometidos a cirugía cardiaca y determinar si existe una asociación entre la presencia de BIA y la aparición de FA postoperatoria. Método: Se incluyeron un total de 207 pacientes. Se definió BIA parcial como onda P > 120 ms. Se definió BIA avanzado como onda P > 120 ms con morfología bifásica en derivaciones inferiores. Se determinó la frecuencia de aparición de FA postoperatoria y se realizó un análisis comparativo entre los pacientes que presentaron y los que no presentaron esta arritmia. Resultados: La prevalencia de BIA fue del 78.3% (parcial, 66.2%; avanzado, 12.1%). La frecuencia de aparición de FA fue del 28.5% de forma global, siendo mayor en los pacientes con BIA avanzado (44%) comparado con pacientes con BIA parcial (27.7%) y sin BIA (24.4%). Los pacientes que presentaron FA fueron significativamente mayores, con niveles más elevados de NTproBNP y presentaron mayor prevalencia de dilatación auricular y de patología tiroidea. El análisis multivariable demostró una asociación independiente entre BIA avanzado y FA postoperatoria. Conclusiones: El BIA es una entidad frecuente en pacientes sometidos a cirugía cardiaca. En nuestro estudio, el BIA avanzado se asocia de forma independiente con una mayor frecuencia de FA postoperatoria en pacientes menores de 65 años sometidos a cirugía cardiaca.

Abstract Objective: Interatrial block (IAB) is a well-known entity that is associated with an increased risk of atrial fibrillation (AF). This association is called Bayes' syndrome. The aim of our study was to define the prevalence of IAB among patients younger than 65 years undergoing cardiac surgery and determine whether there is an association between the presence of interatrial conduction delay and postoperative atrial fibrillation (POAF). Method: A total of 207 patients were enrolled. Partial IAB was defined as P-wave > 120 ms. Advanced IAB was defined as P-wave > 120 ms + biphasic morphology in the inferior leads. Ocurrence of POAF was assessed and a comparative analysis was conducted between patients that did and did not develop AF. Results: IAB prevalence was 78.3% (partial 66.2%, advanced 12.1%). POAF occurred in 28.5% of all patients, and was more frequent among patients with advanced IAB (44%) compared to 27.7% and 24.4% of POAF among patients with partial IAB and without IAB, respectively. Patients who developed POAF were significantly older, had significantly higher NTproBNP, higher prevalence of atrial enlargement and thyroid disease. After multivariate analysis, advanced IAB was found to be independently associated with POAF. Conclusions: IAB is a frequent finding among patients undergoing cardiac surgery. According to our results, advanced IAB is independently associated with POAF in younger patients (< 65 years) undergoing cardiac surgery.

Analysis of the Association Between Electrocardiographic P-wave Characteristics and Atrial Fibrillation in the REGICOR Study.

INTRODUCTION AND OBJECTIVES: Atrial fibrillation (AF) is the most common clinically significant cardiac arrhythmia. P-wave duration and interatrial blocks (IAB) have been reported to be associated with AF. Our aim was to determine the individual and combined association of P-wave duration and advanced IAB morphology with AF. METHODS: We designed an age-, sex-, and survey-matched case-control study nested in a population-based cohort (REGICOR: REgistre GIroní del COR). Two different surveys recruited a total of 9380 participants from 1999 to 2005; all participants were invited to a second examination between 2009 and 2013. For the present study, we selected participants aged 25 to 79 years with follow-up through the end of the study. All electrocardiograms were analyzed by 2 observers to determine P-wave duration and morphology (normal, partial, or advanced IAB). RESULTS: The median follow-up was 7.12 years. Eighty participants presented with AF, had a legible baseline electrocardiogram, and were included in the study, along with 160 controls. P-wave duration and the presence of partial or advanced IAB were associated with AF. When P-wave duration and morphology were considered together, only P-wave duration (≥ 110 milliseconds) showed an independent and strong association with AF. The odds ratio for AF of P-wave duration between 110-119, 120-129 and ≥ 130 milliseconds vs < 110 milliseconds were 5.33; 95%CI, 1.74-16.33, 5.08; 95%CI, 1.73-14.90 and 5.44; 95%CI, 1.95-15.15, respectively. CONCLUSIONS: A P-wave longer than 110 milliseconds increases the risk of AF. Advanced IAB morphology did not seem to provide an additional AF risk beyond that of P-wave duration.

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 <

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

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 «Bayés' syndrome¼