3D electroanatomical mapping is less sensitive to atrial remodeling in estimation of true left atrial volume than...

Left atrial (LA) enlargement has been identified as a predictor of worse clinical outcome after catheter ablation for atrial fibrillation (AF). We investigated the correspondence of LA size parameters assessed by echocardiography, CT and 3D electroanatomical mapping in patients with AF treated by catheter ablation.

We analyzed echocardiographic LA volume measurements by disc summation method (LAV_DISC), computed tomography (LAV_CT) and 3D electroanatomical mapping (LAV_CARTO) in 100 pts. (71% males; aged 63 ± 8 years; paroxysmal AF in 55% of patients).

Mean LAV_DISC was 83 ± 25 ml (median: 115; IQR: 98-140 ml), mean LAV_CT was 120 ± 34 ml (median: 115; IQR: 98-140 ml) and mean LAV_CARTO was 123 ± 36 ml (median: 118; IQR: 99-132 ml). Pearson's correlation coefficient between LAV_DISC a LAV_CT was 0.6 (p < 0.0001) and between LAV_CARTO and LAV_CT was 0.79 (p < 0.0001). There was a significant difference between the two correlation coefficients (p < 0.004). The absolute difference between LAV_CARTO and LAV_CT (3.5 (95% CI -42 - 43) ml) was significantly lower (p < 0.0001) as compared to LAV_DISC and LAV_CT (- 39 (95% CI -102 - 24) ml). In opposite to LAV_DISC, the bias between LAV obtained by CT and CARTO did not differentiate according to presence of spherical remodeling (1.7 ± 28 vs. vs. 5.1 ± 31 ml). Only presence of sinus rhythm was significant and independent covariate of the difference between CARTO and CT-derived LAVs by multivariate regression analysis.

Even though LA volumes evaluated by 3D-electroanatomical mapping have quite good accuracy, the precision is low. For volumes estimated by echocardiography, both precision and accuracy are low.