[Clinical, electrical and echocardiographic characteristics of patients with advanced interatrial block]. / Características clínicas, eléctricas y ecocardiográficas de los pacientes con bloqueo interauricular avanzado.

El haz de Bachmann se compone de un conjunto de fibras miocárdicas paralelas y especializadas, responsables del 80% de la conducción interauricular. Discurre por las paredes anterosuperiores auriculares, y su afectación da lugar al bloqueo interauricular (BIA); éste puede ser: a) parcial (BIA-p) si la conducción está retrasada (en el ECG produce una onda P ≥ 120 ms) o b) avanzado (BIA-a) si está del todo interrumpida y la despolarización auricular izquierda (AI) ocurre en dirección retrógrada caudocraneal (la onda P es ≥ 120 ms y bifásica +/- en las derivaciones inferiores II, III y VF)1.

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.

Update on Bayés' syndrome: the association between an interatrial block and supraventricular arrhythmias.

INTRODUCTION: The past few years have given rise to extensive research on an interatrial block and its clinical relevance, mainly its association with supraventricular arrhythmias. In 2015, the authors of this article reviewed the Bayes syndrome for the first time and after three years there has been so much evidence accumulated that it seems reasonable to rewrite an update, based fundamentally on the new findings. Focused on its relationship with cardioembolic strokes, today efforts are being targeted at understanding its pathophysiology, its diagnosis, and its prognostic implications, in order to learn if it should be treated. Areas covered: A non-systematic review of the literature was developed using the Pubmed and Cochrane databases, focusing on randomized clinical trials and large observational studies that evaluated new physiopathological and epidemiological aspects, new clinical scenarios in which it has been assessed and its association with dementia. Finally, those studies that proposed new possible treatments were reviewed. Expert commentary: Interatrial block is not only a predictor of supraventricular arrhythmias, is a subclinical disease that might be considered as a marker of risk for adverse outcomes. Although there is some evidence to suggest that early treatment may be beneficial, potential therapies have yet to be investigated.