Bayes Syndrome and Imaging Techniques

Abstract

Interatrial block (IAB) is due to disruption in the Bachmann region (BR). According to whether interatrial electrical conduction is delayed or completely blocked through the BR, it can be classified as IAB of first, second or third degree. On the surface electrocardiogram, a P wave ≥ 120 ms (partial IAB) is observed or associated to the prolongation of the P wave with a biphasic (positive / negative) morphology in the inferior leads (advanced IAB). Bayes syndrome is defined as an advanced IAB associated with atrial arrhythmia, more specifically atrial fibrillation. Objective and Conclusion: The purpose of this review is to describe the latest evidence about an entity considered an anatomical and electrical substrate with its own name, which may be a predictor of supraventricular arrhythmia and cardioembolic cerebrovascular accidents, as well as the role of new imaging techniques, such as echocardiographic strain and cardiac magnetic resonance imaging, in characterizing atrial alterations associated with this syndrome and generally in the study of anatomy and atrial function.

Bayés’ Syndrome—A Comprehensive Short Review

“…The atrial fibrotic process in the LA can be assessed by various methods, the gold standard being cardiac magnetic resonance imaging (CMR). Additionally, new echocardiographic techniques, like myocardial deformation imaging (strain, strain rate) using speckle tracking can deliver indirect information about the fibrotic process [19].…”

“…The representative of the LA size is not its antero-posterior diameter, but its volume, measured by two-dimensional, or-recently-three-dimensional methods. Determining the reservoir function, reflected by the difference between the maximum (before the mitral valve opens) and the minimum volume (when the mitral valve closes), is the most important in this regard [19].…”

“…As a result, conditions that modify the interstitial space, such as fibrosis, can be identified by delayed myocardial enhancement sequences: myocardial fibrotic areas are hyperintense, while healthy regions have a hypointense or null aspect. At the level of atria, fibrotic changes can be seen as fine areas of delayed enhancement, and can be quantified using the Utah classification system (from I to IV) [19]. Another CMR-derived technique that could be used to determine fibrosis is the T1 sequence, which calculates the myocardial T1 relaxation time during a 10-s voluntary apnea.…”

“…Another CMR-derived technique that could be used to determine fibrosis is the T1 sequence, which calculates the myocardial T1 relaxation time during a 10-s voluntary apnea. This method has the disadvantage of high cost, the need for a high level of experience and the low availability for current clinical practice [19]. 3D reconstruction of 3T late gadolinium enhancement CMR allows visualization of atrial fibrosis in patients with IAB, showing the involvement of the upper part of the septum, where the BB is situated [17].…”

Cerebral Embolism Beyond Atrial Fibrillation: Interatrial Block

“…These concepts have been accepted in a consensus paper [8] and their characteristics follow: To perform a good measurement of the P-wave duration, it is important to define the interval between the earliest detection of the P-wave in any lead of the frontal plane and the lead were the end of the P-wave is detected. Other methods to detect the presence of IAB are the vectocardiogram, and invasive/noninvasive electro-mapping techniques [16,17].…”