Abstract
AIMS: Reduced left atrial (LA) mechanical function associates with atrial myopathy and adverse clinical endpoints in atrial fibrillation (AF) patients; however, conventional 2D imaging modalities are limited by atrial foreshortening and sub-optimally capture 3D LA motion. OBJECTIVES: We set out to test the hypothesis that 3D LA motion features from 4D (3D + time) retrospective gated computed tomography (RGCT) associate with AF phenotypes and predict AF recurrence in patients undergoing catheter ablation. METHODS AND RESULTS: Sixty-nine AF patients (60.8 ± 12.2 years, 39% female, 30% non-paroxysmal AF) who were indicated for CT coronary angiography including a RGCT protocol in sinus rhythm prior to ablation were included. We measured 3D LA endocardial motion by optimized 3D feature tracking and calculated 3D global and regional phasic strain and peak strain rates (SRs). AF recurrence was observed in 18 patients (26%) at 1-year. Global reservoir strain (P < 0.05) and contractile strain and SR (both P < 0.01) were reduced in patients with vs. those without recurrent AF. Global and anterior wall contractile SR were more predictive of recurrent AF than LA volume index (area under the curve, AUC: 0.74, 0.77, and 0.68, respectively). Reduced global conduit SR and septal reservoir strain were more strongly associated with non-paroxysmal AF than CHADS2-VASc (AUCs: 0.74, 0.75, and 0.59, respectively). CONCLUSION: Reduced passive and active 3D LA motion from 4D RGCT associates with more advanced AF and AF recurrence post-ablation, respectively. Future work should extend this approach to larger populations, with new low-radiation CT technologies to widen its applicability.