Progression of atrial remodeling in patients with high-burden atrial fibrillation: Implications for early ablative intervention

Background Advanced atrial remodeling predicts poor clinical outcomes in human atrial fibrillation (AF). Objective The purpose of this study was to define the magnitude and predictors of change in left atrial (LA) structural remodeling over 12 months of AF. Methods Thirty-eight patients with paroxysmal AF managed medically (group 1), 20 undergoing AF ablation (group 2), and 25 control patients with no AF history (group 3) prospectively underwent echocardiographic assessment of strain variables of LA reservoir function at baseline and at 4, 8, and 12 months. In addition, P-wave duration (P_max,, P_mean) and dispersion (P_dis) were measured. AF burden was quantified by implanted recorders. Twenty patients undergoing ablation underwent electroanatomic mapping (mean 333 ± 40 points) for correlation with LA strain. Result Group 1 demonstrated significant deterioration in total LA strain (26.3% ± 1.2% to 21.7% ± 1.2%, P <.05) and increases in P_max (132 ± 3 ms to 138 ± 3 ms, P <.05) and P_dis (37 ± 2 ms to 42 ± 2 ms, P <.05). AF burden ≥10% was specifically associated with decline in strain and with P-wave prolongation. Conversely, group 2 manifest improvement in total LA strain (21.3% ± 1.7% to 28.6% ± 1.7%, P <.05) and reductions in P_max (136 ± 4 ms to 119 ± 4 ms, P <.05) and P_dis (47 ± 3 ms to 32 ± 3 ms, P <.05). Change was not significant in group 3. LA mean voltage (r = 0.71, P =.0005), percent low voltage electrograms (r = -0.59, P =.006), percent complex electrograms (r = -0.68, P =.0009), and LA activation time (r = -0.69, P =.001) correlated with total strain as a measure of LA reservoir function. Conclusion High-burden AF is associated with progressive LA structural remodeling. In contrast, AF ablation results in significant reverse remodeling. These data may have implications for timing of ablative intervention.