The Bachmann's bundle connection: from obesity and aging to atrial arrhythmia development

In recent years, Bachmann's bundle (BB), a band of cardiac muscle that enables electrical conduction from the heart's right atrium to the left atrium, has drawn significant interest from the scientific community. It has been identified as a branch of the anterior interatrial pathways connecting the sinoatrial node to the atrioventricular node, departing at the level of the superior vena cava. It is now understood that BB serves as a preferential pathway for interatrial conduction, and structural abnormalities in BB can result in interatrial block, which is associated with the onset of atrial fibrillation and flutter. Studies have also demonstrated that within BB, the incidence of conduction abnormalities (such as conduction delay and conduction block) increases with age. In addition, recently published studies have shown that in obese patients, areas of low voltage are mainly located over the anterior wall, where BB is mostly present, suggesting that the deposition of epicardial fat may predominantly affect the function of this important structure in the heart. Therefore, BB is undoubtedly a structure that merits further investigation, as its role remains unclear, particularly regarding its impact on the development of new treatments. The goal of this review is to describe structural and functional changes in BB in obese, elderly patients as well as those with cardiovascular abnormalities.