Left atrial posterior wall electric remodelling and the frequency of atrial fibrillation episodes in paroxysmal atrial fibrillation

Background The left atrial posterior wall (LAPW) is a common site for low-voltage zones (LVZs) and fragmented electrograms. Furthermore, the LAPW is densely innervated by autonomic ganglia, where high adrenergic tone situations would exacerbate the posterior wall remodelling, reducing local voltage, triggering Atrial Fibrillation (AF) episodes and increasing AF burden. These properties have been linked to more advanced and persistent AF. However, studies linking posterior wall local voltage with frequency of AF episodes in paroxysmal AF remains limited. Purpose To investigate whether the LAPW voltage elicited by high-density electroanatomical mapping would correlated with the frequency of AF episodes during the 1-year of continuous rhythm monitoring prior to AF ablation for paroxysmal AF. Methods We conducted a retrospective analysis from an AF registry who underwent AF ablation. All patients had implantable loop recorder (ILR) data as part of the AF registry. Pre-ablation high-density electroanatomical mapping was performed. The voltage map of the posterior wall and the ILR rhythm monitoring data were analyzed (Figure 1). This study was performed in alignment with the institutional ethical guidelines and local practices. Results In total 14 patients were included, mean age was 58.8± 8.9 with 64.3% male participants. Average Left Atrial Volume Index was 36.5± 9 ml/m2 with average left ventricular ejection fraction of 57.4± 3.7%. All patient were diagnosed with paroxysmal AF. Thirteen patients had de novo AF ablation, and one patient had previous Cryoablation AF ablation The median total number of AF episodes recorded was 128 episodes (19-223), with median 1-year AF burden of 3.6% (0.5-5.9). Average LAPW voltage was 3.3± 1.2 mV. The number of AF episodes were inversely correlated with posterior wall average voltage with statistical significance (Rho of -0.75 with p-value of 0.002) (Figure 2A and B). Conclusion During continuous monitoring for 1 year prior to AF ablation, the number of recorded AF episodes inversely correlates with the average posterior wall voltage. This points towards even in paroxysmal AF with low burden, LAPW low voltage suggest worse disease and high number of episodes.Figure 1Figure 2