The left hand as a model for the right atrium: a simple teaching tool.

AIMS

Knowledge of the complex three-dimensional anatomy of the right atrium is mandatory for the electrophysiologist and interventional cardiologist, but its understanding remains difficult. We hypothesized that the left hand, loosely clenched, is a good three-dimensional model to understand the position of the different anatomical and electrical regions in the right atrium. For validation, we compared the hand with an endocast that had been prepared from an adult human right atrium and with a three-dimensional electro-anatomical CT image of the right atrium.

METHODS AND RESULTS

Views of the left hand were photographed from various angles to replicate as closely as possible the standard fluoroscopic views. Using the nomenclature of the bones of the hand, we assigned the different regions of the hand to represent regions and structures of the right atrium. An endocast was prepared from an adult human right atrium. A three-dimensional electro-anatomical right atrial map with CT integration (CartoMerge) was used as the gold standard for the exact localization of electrical regions such as the sinus node (SN), bundle of His, and slow pathway region. Using the left hand, it is possible to mark the free wall, terminal crest, appendage, septal surface, oval fossa and orifices of the caval veins, tricuspid valve, and coronary sinus. We also marked the anticipated locations of the SN, His bundle, triangle of Koch, slow pathway region, inferior isthmus, and right atrial insertion of Bachmann's bundle. When compared with an endocast and a three-dimensional electro-anatomical CT image, the position and orientation of the marked regions were deemed to be anatomically correct.

CONCLUSION

Compared with an endocast and a CT-guided electro-anatomical reconstruction of the right atrium, the left hand is a reliable model to understand the position and orientation of the different anatomical and electrical regions in the right atrium. Although an oversimplification of the complex right atrial anatomy, this model is 'handy' to understand, guide, and teach electrophysiological and interventional procedures.