Evaluation of left atrial remodeling by 2D-speckle-tracking echocardiography versus by high-density voltage mapping in patients with atrial fibrillation

Background: Strain imaging during left atrial (LA) reservoir phase (LASr) is used as a surrogate for LA structural remodeling and fibrosis. Atrial fibrillation (AF) patients with >5% low-voltage zones (LVZs) obtained by 3D-electro-anatomical-mapping have higher recurrence rate post-ablation. We investigated the relationship between LA remodeling using two-dimensional-speckle-tracking echocardiography (2D-STE) and high-density voltage mapping in AF patients.

Methods: A prospective study of 42 consecutive patients undergoing AF ablation. 2D-echo, 2D-STE, and high-density contact LA bipolar voltage maps were constructed before ablation. LVZs were determined with different bipolar amplitudes and their ratio per patient's LA area were investigated for correlation with LASr. We compared 2D-LASr results in patients with LVZs ≥ 5% (LVZs group) versus those with LVZ < 5% (non-LVZs group).

Results: Compared with non-LVZs group (n = 15), LVZs group (n = 27) included significantly older patients, more women, more persistent AF, higher CHA₂ DS₂ -VASc score, higher E/A ratio and higher LA volume index (p < .05). LVZs group had lower %LASr values (12.4 ± 5.9% vs. 21.1 ± 6.3, respectively; p<.001). LVZs% in different amplitudes (<0.1 mV, <0.2 mV, and <0.5 mV) were negatively correlated with %LASr (r = -.63, r = -.68, and r = -.72, respectively; p< .001). Atrial strain thresholds for LVZs ≥ 5% in amplitudes <0.1 mV, <0.2 mV, and <0.5 mV were associated with %LASr 12.98, 16.16 and 19.55, respectively; p< .05). In a multivariate analysis, %LASr was the only independent indicator of LVZs (OR, 0.8; 95% CI, 0.6-0.9; p= .04).

Conclusions: LVZs ≥ 5% has a negative association with atrial %LASr. Thus, a simple 2D-STE measurement of %LASr can be used as a noninvasive method to evaluate significant LA remodeling and fibrosis in AF patients.