Effect of presenting rhythm on image integration to direct catheter ablation of atrial fibrillation

Applications of multimodality imaging for left atrial catheter ablation

Atrial arrhythmias, including atrial fibrillation and atrial flutter, may be treated through catheter ablation. The process of atrial arrhythmia catheter ablation, which includes patient selection, pre-procedural planning, intra-procedural guidance, and post-procedural assessment, is typically characterized by the use of several imaging modalities to sequentially inform key clinical decisions. Increasingly, advanced imaging modalities are processed via specialized image analysis techniques and combined with intra-procedural electrical measurements to inform treatment approaches. Here, we review the use of multimodality imaging for left atrial ablation procedures. The article first outlines how imaging modalities are routinely used in the peri-ablation period. We then describe how advanced imaging techniques may inform patient selection for ablation and ablation targets themselves. Ongoing research directions for improving catheter ablation outcomes by using imaging combined with advanced analyses for personalization of ablation targets are discussed, together with approaches for their integration in the standard clinical environment. Finally, we describe future research areas with the potential to improve catheter ablation outcomes.

Relationship between intended sites of RF ablation and post-procedural scar in AF patients, using late gadolinium enhancement cardiovascular magnetic resonance

BACKGROUND

Radiofrequency (RF) ablation of the left atrium (LA) in patients with atrial fibrillation (AF) is guided by electroanatomic mapping systems. The cardiovascular magnetic resonance (CMR) late gadolinium enhancement (LGE) technique can detect scar after ablation. Direct comparisons between the locations of intended RF ablation sites and locations of scar formation in the LA have not been performed.

OBJECTIVE

This study sought to develop and use a method for comparing the sites of RF application with the sites of post-procedural scar formation in the LA.

METHODS

A method for rigid registration of CMR LGE images with electroanatomic mapping data (Carto data), visualization of the registered data sets, and quantification of the correlations was developed and used in 19 studies of patients with AF. The distance between the Carto points and the CMR LA surface was measured as the mean integration error. The distance between each Carto ablation and the nearest scar was measured. The gaps in sites of LGE and in Carto ablation were also assessed qualitatively, in 6 sectors of each PV.

RESULTS

The custom registration method provided a mean integration error between Carto and CMR of 2.7 +/- 0.7 mm. The average distance between Carto and LGE scar was 3.6 +/- 1.3 mm. Qualitatively, 20% of sectors with sites of Carto ablation showed no evidence of LGE.

CONCLUSION

There was a visual and quantitative correspondence between Carto ablation sites and LGE scar, but for 20% of Carto ablation sites there was no visible corresponding LGE.

CT applications in electrophysiology

In recent years, extraordinary advances have been made in the management of cardiac arrhythmias. Increasingly complex procedures are being performed, and the breadth of conditions for which invasive arrhythmia therapy is indicated continues to grow. In addition to atrial and ventricular ablation procedures for treating arrhythmias, implantable defibrillators and biventricular pacemakers for cardiac resynchronization therapy have made electrophysiology an important part of heart failure management.