Interatrial blocks: diagnosis and clinical significance

In 1979 Bayés de Luna described interatrial blocks (IAB). Following the same principle of classification of blocks in other structures of the heart, he divided them into first (partial IAB), second (atrial aberrancy) and third degree (advanced IAB). Atypical forms of these blocks were recently described. There is evidence that delays or blocks of conduction in the Bachmann bundle constitute the mechanistic basis of these blocks. The association between IAB, mainly those of advanced grade, and atrial tachyarrhythmias is already constituted science, and is referred to by the medical community as Bayés syndrome. IABs are also associated with the occurrence of ischaemic stroke and recurrence of atrial fibrillation in several scenarios. This review presents classical aspects and sheds light on the interpretation of this electrocardiographic pattern in clinical practice.