Bayés’ syndrome: the association between interatrial block and supraventricular arrhythmias

Abstract

The past few years have given rise to extensive research on atrial conduction disorders and their clinical relevance. Most notably, an association between interatrial block and supraventricular arrhythmias has been discovered. This disorder, recently termed ‘Bayés’ syndrome’, has important clinical implications. In this article, the authors review normal atrial conduction and associated disorders. A particular focus is placed on Bayés’ syndrome and the relationship between interatrial block and supraventricular arrhythmias in different clinical scenarios. The report also outlines the current progress in the study of this syndrome and highlights areas requiring further investigation.

Keywords:

• atrial aberrancy
• atrial fibrillation
• atrial flutter
• atrial remodeling
• Bachmann’s bundle
• Bayés’ syndrome
• interatrial block
• magnetocardiography
• stroke
• supraventricular arrhythmia

Financial & competing interests disclosure

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.

No writing assistance was utilized in the production of this manuscript.

Key issues

• Under normal circumstances, the majority of interatrial conduction occurs through Bachmann’s bundle, a fast conduction tract that arises from the anterior internodal pathway. To a lesser extent, interatrial conduction also occurs at the fossa ovalis and coronary sinus. Typically interatrial block (IAB) is the result of a block in the Bachmann’s bundle pathway.

• IAB can be classified as partial or advanced. In partial IAB, the only ECG abnormality is a P-wave duration ≥120 ms. In advanced IAB, the P-wave duration is also ≥120 ms, with the addition of a negative final component in the inferior leads (II, III and VF). This negative component is a reflection of retrograde activation of the left atrium due to a complete block in the Bachmann’s bundle.

• IAB and left atrial enlargement are two separate entities as IAB frequently occurs in the absence of any atrial enlargement. However, advanced IAB is commonly present in the setting of left atrial enlargement, making it a sensitive marker of this pathology.

• In 1988, Bayés de Luna identified an important association between IAB and supraventricular arrhythmias. This disorder, now referred to as ‘Bayés’ syndrome’, has important clinical implications. Recent evidence has identified IAB as a valuable predictor of supraventricular arrhythmias.

• Advanced IAB is a strong predictor of atrial fibrillation (AF) in various clinical scenarios. This includes the prediction of: Recurrent AF following pharmacologic cardioversion, recurrent AF following pulmonary vein isolation for paroxysmal AF, new-onset AF following cavotricuspid isthmus ablation for typical atrial flutter and new-onset AF in patients with Chagas cardiomyopathy and ICDs. In addition to this, IAB is an independent predictor of new-onset AF in patients with severe heart failure undergoing cardiac resynchronization device implantation.

• Severe obstructive sleep apnea is also associated with IAB. The high frequency of IAB in these patients could explain the development of supraventricular arrhythmias such as AF.

• Early evidence suggests that patients with IAB might benefit from treatment with antiarrhythmic therapy; however, larger studies are needed to confirm the risks and benefits of this treatment.

• IAB may be associated with a greater risk of cardioembolic stroke, suggesting that these patients might benefit from starting early anticoagulation therapy. Larger studies are currently needed to further evaluate this hypothesis.

Notes