Interatrial conduction in the mechanisms of atrial fibrillation: from anatomy to cardiac signals and new treatment modalities.

Areas of slow conduction and conduction block are important prerequisites for re-entry known to underlie atrial fibrillation (AF). Experimental and clinical data show that AF is associated with global lowering of atrial propagation velocity and the presence of defects in the interatrial conduction routes. The increasing data from anatomical studies demonstrate the possible prerequisites for conduction disturbances that could be primarily because of anatomical variability in interatrial connections or because of age-related development of fibrotic changes in the atrial musculature. More detailed descriptions of the structure and function of the interatrial connections other than Bachmann's bundle have become available and, as a result, the role of these connections in the mechanisms of AF is increasingly appreciated. Interatrial pacing studies show promising results, but further studies on larger amounts of materials are required in order to identify the population of patients who would benefit more effectively from this treatment as well as the optimal pacing technique. Therefore, more extensive documentation is required before therapeutic modalities aimed at improving interatrial conduction will become a part of the clinical routine in the management of AF patients.