Dynamic multidimensional imaging of the human left atrial appendage

Aims: The human left atrial appendage (LAA) is a region of increasing interest as a target for intervention. We sought to improve insight into the anatomy of this region using computed tomography (CT). Methods and results: Multidimensional cardiac reconstruction (whole heart and isolated left atrium) from CT images was performed in each of three groups: (i) patients without atrial fibrillation (AF, n =10); (ii) patients with intermittent (paroxysmal) AF (n = 25); (iii) patients with continuous (persistent) AF (n = 10). Indices included LAA morphology, anatomical relationships, dimensions, angulation, and motility. There was substantial interindividual variation in each index. LAA morphologic differences were associated with variations in anatomical relationships. LAA dimensions in AF patients exceeded those in patients without AF, but angulation and motility were similar. The LAA could be subdivided into proximal and distal portions, each of which had distinct morphology and anatomical relationships. Dimensions in men tended to exceed those in women. Conclusion: Regardless of AF history, there is broad variation in LAA morphology, anatomical relationships, dimensions, angulation, and motility. These observations may have importance for the development of technologies for therapy delivery in this region.