Multi-modality imaging to assess left atrial size, anatomy and function.

The left atrium (LA) anterior-posterior diameter was one of the first standardised echocardiographic parameters. However, the clinical importance of LA size assessment has been neglected for some time. Recent population-based studies have demonstrated the prognostic value of LA size for long-term outcome. Furthermore, with new dedicated techniques such as tissue Doppler imaging, it has become feasible to assess (regional) LA function. In addition, the introduction of catheter ablation procedures has changed the treatment of patients with drug-refractory atrial fibrillation (AF) dramatically. New image integration systems have become available for these catheter ablation procedures. With the use of image integration systems, a real anatomical "roadmap" of the LA is provided for catheter ablation procedures. All these factors may explain the renewed interest in LA anatomy. In this article, the importance of assessment of LA size and LA anatomy is discussed. Furthermore, the various imaging modalities that are available for the non-invasive visualisation of the LA will be reviewed. In addition, the role of these imaging techniques in catheter ablation procedures for AF will be discussed.