Measurement of left atrial volume in patients undergoing ablation for atrial fibrillation: comparison of angiography and electro-anatomic (CARTO) mapping with real-time three-dimensional echocardiography.

AIMS: Left atrial (LA) volume can be determined during radiofrequency catheter ablation (RFCA) of atrial fibrillation (AF) with angiography or electro-anatomic (CARTO) mapping. We compared these volumes with LA volume measured using transthoracic real-time three-dimensional echocardiography (3DE).

METHODS AND RESULTS: One hundred and twenty-seven consecutive patients undergoing RFCA for AF were studied using biplane pulmonary vein angiography with opacification of the LA. LA volume was calculated from the diameter measurements with a formula using an ellipsoid model. A subset of 22 patients also underwent LA volume determination by CARTO mapping. These volumes were then correlated with LA volume determined non-invasively by real-time 3DE. Linear regression showed a significant correlation between LA volume determined by angiography and 3DE volume (r = 0.56, P < 0.0001). Bland-Altman analysis showed a bias of 38 +/- 22 ml by the angiographic method. LA volume measured using CARTO correlated better (r = 0.67, P < 0.001), but 3DE yielded smaller values (mean difference of -30 +/- 19 ml).

CONCLUSION: LA volume determination by angiography and CARTO mapping correlate significantly with 3DE volume. However, both invasive techniques yield larger values for LA volume. The results indicate that LA volume obtained by angiography or CARTO should not be used as baseline value for non-invasive follow-up of LA remodelling by 3DE.