The anatomy of atrial conduction: a review of anatomical landmarks integrated with computed tomographic virtual dissection to provide a road map for right atrial pacing.

Pacing of the atrial chambers has recently gained increased attention. Major barriers, however, relate to the understanding of the underlying anatomy relative to fluoroscopic positioning of pacing leads, and on the reliance of using the morphology of the electrocardiographic P-wave in guiding intended capture of the preferential pathways for interatrial conduction. There remains a gap in knowledge both in the understanding of the location of the sinus and atrioventricular nodes, and the arrangement of the intervening myocardial preferential conduction pathways, coupled with an appreciation of how to apply such understanding towards guiding and improving the success rate of pacing procedures. In this review, we delineate the three-dimensional anatomy of the atriums, and show how this relates to the pathways for atrial conduction. Although we recognize that, as yet, the locations of the sinus and atrioventricular nodes cannot be shown directly when using clinical imaging, we describe and illustrate how interrogation using three-dimensional cardiac computed tomography is now able accurately to predict their location, along with the preferential pathways of electrical atrial activation. We submit that such understanding may provide practical guidance for those undertaking pacing procedures, permitting the personalization of cardiac care as related to atrial conduction.