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ScienceDirect Journal of Electrocardiology 48 (2015) 133 – 134 www.jecgonline.com
Editorial
The time for naming the Interatrial Block Syndrome: Bayes Syndrome The inter-ventricular conduction system of the heart is a well-recognized anatomical structure, termed the Purkinje System that is distinguishable from the working myocardium. It includes a common bundle, termed the His Bundle and its branches and fascicles; that have the specialized functions of conducting electrical impulses rapidly to optimally synchronize the contraction of the myocardium. Impaired function of its individual components results in typical changes on electrocardiogram, known as “block”. There are also specialized structures (nodes): the sino-atrial (SA) node high in the right atrium that is the primary generator of the cardiac impulse, and the atrio-ventricular (AV) node low in the right atrium that slows or impedes impulse conduction. These anatomic structures, their specialized functions, and their ECG classifications are well established for years; supported with evidence from numerous experimental animal and clinical studies and computer simulations. A different situation can be seen regarding the description and classification of ECG in the altered conduction within the atria. There are probably two main issues that contribute to this different approach: the characteristics of the P wave, and the “specialized” impulse conduction structures in the atria. The P wave reflecting the atrial activation is of low voltage, and the pathologic changes are less pronounced and explicit as compared those of the QRS complex; consequently it is more difficult to identify distinguishable characteristic alterations. Also, in contrast to the specialized Purkinje cells of leading as a rapidly conduction network from the AV node through the ventricular endocardium, preferential conduction in the atria depends only on the organization of their myocardial cells [1]. The impulse-conducting pathways identified in the atria have been termed “inter-nodal tracks” and the inter-atrial “Bachmann bundle” [2]. Bachmann bundle (BB) is a broad band of cardiac muscle that passes from the right to the left atrium [2,3], and is considered to have a fundamental role in inter-atrial conduction. However, BB does not show anatomical and functional characteristics of specialized conduction; however, as a muscular inter-atrial “preferential pathway”, it can be blocked analogous to blocks in the interventricular Purkinje network. The first case of advanced inter-atrial block was described in 1956 [4]. A complex view on the topic of inter-atrial block (IAB) has been provided by the “school” represented by Antonio Bayes de Luna. In this issue, the review paper by Bayes de http://dx.doi.org/10.1016/j.jelectrocard.2014.12.022 0022-0736/© 2015 Elsevier Inc. All rights reserved.
Luna and coauthors [5] summarizes the concept of an interatrial block (IAB) syndrome due to conduction impairment in Bachmann's Bundle. IAB as a syndrome, was first described by Bayes de Luna 30 years ago [6]. Supporting papers covering most aspects of the pathophysiology, the electrocardiographic and vectorcardiographic descriptions, and the association with supraventricular tachyarrhythmias were published; including the consensus paper in 2012 [6–8]. The current knowledge of the topic by this “Bayes de Luna School” shows that advanced AIB associated with supraventricular arrhythmias qualifies for a clinical syndrome. Actually the term “Bayes' syndrome” has been already used in some papers, acknowledging Antoni Bayes de Luna's dedicated work in this field, e.g. [9,10]. The paper in his issue of the JECG [5] stimulates acceptance of the concept that IAB has achieved the stature has achieved the stature to be defined as a complex syndrome, supported by the current level of evidence and accepted by the scientific community. Additionally, it encourages electrocardiologists to enhance their current knowledge regarding the IAB topic, and understanding would benefit from direct evidence from measuring the conduction velocity in Bachman's bundle. This would lead not only to improvement in diagnosis, but also to therapy of conduction impairment. Ljuba Bacharova, MD, DSc, MBA International Laser Center, Bratislava, Slovakia Corresponding author at: International Laser Center Ilkovicova 3, 841 04 Bratislava, Slovak Republic E-mail address: [email protected] Galen S. Wagner, MD, PhD Duke University Medical Research Center Durham, NC, USA References [1] van Campenhout MJ, Yaksh A, Kik C, de Jaegere PP, Ho SY, Allessie MA, et al. Bachmann's bundle: a key player in the development of atrial fibrillation? Circ Arrhythm Electrophysiol 2013;6:1041–6. [2] Bachmann G. The inter-auricular time interval. Am J Physiol 1916;41:309–20. [3] Bachmann G. The significance of splitting of the P-wave in the ECG. Ann Intern Med 1941;14:1702–9.
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Editorial / Journal of Electrocardiology 48 (2015) 133–134
[4] Puech P. L’activite electrique auriculare normal et pathologique. Paris: Masson Edit; 1956. [5] Bayes de Luna A, Conde D, Baranchuk A. Advanced interatrial block as a substrate of supraventricular tachyarrhythmias: a well recognized syndrome. J Electrocardiol 2015 [in this issue]. [6] Bayes de Luna A, Fort de Ribot R, Trilla E, Julia J, Garcia J, Sadurni J, et al. Electrocardiographic and vectorcardiographic study of interatrial conduction disturbances with atrial retrograde activation. J Electrocardiol 1885;18:1–13. [7] Bayes de Luna A, Cladellas M, Oter R, Torner P, Guindo J, Martí V, et al. Interatrial conduction block and retrograde activation of the left atrium
and paroxysmal supraventricular tachyarrhythmia. Eur Heart J 1988;9:1112–8. [8] Bayes de Luna A, Platonov P, Cosio FG, Cygankiewicz I, Pastore C, Baranowski R, et al. Interatrial blocks: a separate entity from left atrial enlargement: a consensus report. J Electrocardiol 2012;45:445–51. [9] Conde D, Baranchuk A. Bloqueo interauricular como sustrato anatomico-electrico de arritmias supraventriculares: Sindrome de Bayes. Arch Mex Cardiol 2014;84:32–40. [10] Conde D, Baranchuk A. A Bayes' syndrome: what every cardiologist should know. Rev Argent Cardiol 2014;82:237–9.
ScienceDirect Journal of Electrocardiology 48 (2015) 133 – 134 www.jecgonline.com
Editorial
The time for naming the Interatrial Block Syndrome: Bayes Syndrome The inter-ventricular conduction system of the heart is a well-recognized anatomical structure, termed the Purkinje System that is distinguishable from the working myocardium. It includes a common bundle, termed the His Bundle and its branches and fascicles; that have the specialized functions of conducting electrical impulses rapidly to optimally synchronize the contraction of the myocardium. Impaired function of its individual components results in typical changes on electrocardiogram, known as “block”. There are also specialized structures (nodes): the sino-atrial (SA) node high in the right atrium that is the primary generator of the cardiac impulse, and the atrio-ventricular (AV) node low in the right atrium that slows or impedes impulse conduction. These anatomic structures, their specialized functions, and their ECG classifications are well established for years; supported with evidence from numerous experimental animal and clinical studies and computer simulations. A different situation can be seen regarding the description and classification of ECG in the altered conduction within the atria. There are probably two main issues that contribute to this different approach: the characteristics of the P wave, and the “specialized” impulse conduction structures in the atria. The P wave reflecting the atrial activation is of low voltage, and the pathologic changes are less pronounced and explicit as compared those of the QRS complex; consequently it is more difficult to identify distinguishable characteristic alterations. Also, in contrast to the specialized Purkinje cells of leading as a rapidly conduction network from the AV node through the ventricular endocardium, preferential conduction in the atria depends only on the organization of their myocardial cells [1]. The impulse-conducting pathways identified in the atria have been termed “inter-nodal tracks” and the inter-atrial “Bachmann bundle” [2]. Bachmann bundle (BB) is a broad band of cardiac muscle that passes from the right to the left atrium [2,3], and is considered to have a fundamental role in inter-atrial conduction. However, BB does not show anatomical and functional characteristics of specialized conduction; however, as a muscular inter-atrial “preferential pathway”, it can be blocked analogous to blocks in the interventricular Purkinje network. The first case of advanced inter-atrial block was described in 1956 [4]. A complex view on the topic of inter-atrial block (IAB) has been provided by the “school” represented by Antonio Bayes de Luna. In this issue, the review paper by Bayes de http://dx.doi.org/10.1016/j.jelectrocard.2014.12.022 0022-0736/© 2015 Elsevier Inc. All rights reserved.
Luna and coauthors [5] summarizes the concept of an interatrial block (IAB) syndrome due to conduction impairment in Bachmann's Bundle. IAB as a syndrome, was first described by Bayes de Luna 30 years ago [6]. Supporting papers covering most aspects of the pathophysiology, the electrocardiographic and vectorcardiographic descriptions, and the association with supraventricular tachyarrhythmias were published; including the consensus paper in 2012 [6–8]. The current knowledge of the topic by this “Bayes de Luna School” shows that advanced AIB associated with supraventricular arrhythmias qualifies for a clinical syndrome. Actually the term “Bayes' syndrome” has been already used in some papers, acknowledging Antoni Bayes de Luna's dedicated work in this field, e.g. [9,10]. The paper in his issue of the JECG [5] stimulates acceptance of the concept that IAB has achieved the stature has achieved the stature to be defined as a complex syndrome, supported by the current level of evidence and accepted by the scientific community. Additionally, it encourages electrocardiologists to enhance their current knowledge regarding the IAB topic, and understanding would benefit from direct evidence from measuring the conduction velocity in Bachman's bundle. This would lead not only to improvement in diagnosis, but also to therapy of conduction impairment. Ljuba Bacharova, MD, DSc, MBA International Laser Center, Bratislava, Slovakia Corresponding author at: International Laser Center Ilkovicova 3, 841 04 Bratislava, Slovak Republic E-mail address: [email protected] Galen S. Wagner, MD, PhD Duke University Medical Research Center Durham, NC, USA References [1] van Campenhout MJ, Yaksh A, Kik C, de Jaegere PP, Ho SY, Allessie MA, et al. Bachmann's bundle: a key player in the development of atrial fibrillation? Circ Arrhythm Electrophysiol 2013;6:1041–6. [2] Bachmann G. The inter-auricular time interval. Am J Physiol 1916;41:309–20. [3] Bachmann G. The significance of splitting of the P-wave in the ECG. Ann Intern Med 1941;14:1702–9.
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Editorial / Journal of Electrocardiology 48 (2015) 133–134
[4] Puech P. L’activite electrique auriculare normal et pathologique. Paris: Masson Edit; 1956. [5] Bayes de Luna A, Conde D, Baranchuk A. Advanced interatrial block as a substrate of supraventricular tachyarrhythmias: a well recognized syndrome. J Electrocardiol 2015 [in this issue]. [6] Bayes de Luna A, Fort de Ribot R, Trilla E, Julia J, Garcia J, Sadurni J, et al. Electrocardiographic and vectorcardiographic study of interatrial conduction disturbances with atrial retrograde activation. J Electrocardiol 1885;18:1–13. [7] Bayes de Luna A, Cladellas M, Oter R, Torner P, Guindo J, Martí V, et al. Interatrial conduction block and retrograde activation of the left atrium
and paroxysmal supraventricular tachyarrhythmia. Eur Heart J 1988;9:1112–8. [8] Bayes de Luna A, Platonov P, Cosio FG, Cygankiewicz I, Pastore C, Baranowski R, et al. Interatrial blocks: a separate entity from left atrial enlargement: a consensus report. J Electrocardiol 2012;45:445–51. [9] Conde D, Baranchuk A. Bloqueo interauricular como sustrato anatomico-electrico de arritmias supraventriculares: Sindrome de Bayes. Arch Mex Cardiol 2014;84:32–40. [10] Conde D, Baranchuk A. A Bayes' syndrome: what every cardiologist should know. Rev Argent Cardiol 2014;82:237–9.
