Abstract 18630: Variance In Endocardial Voltage Between The Sinus Node And Other Bi-atrial Regions In Patients With Atrial Fibrillation

Abstract

Background: The mechanisms for atrial fibrillation (AF) are unclear but correlate with substrates such as low voltage and CHADS2VASc risk factors, which is a target for AF ablation after the recent ERASE trial. Experimental models of AF show that fibrosis increases near the sinus node, which may explain the link between AF and sinus node dysfunction. However, such data are less clear in patients without global mapping of all regions simultaneously. Hypothesis: We hypothesize that there is a difference in regional endocardial voltages in AF patients mapping globally, specifically between the sinus node and other atrial regions. Methods: We studied N = 57 patients undergoing AF ablation with bi-atrial global endocardial voltage data (19 females, LVEF 58 ± 1.5%). Electrograms were collected using 64 pole basket catheters in the right (RA) and left (LA) atrium for 1 minute. We used custom software to analyze 3D electroanatomic maps (NavX, Abbott, IL) for voltages in 3 predefined regions in the RA near and remote from the sinus node, and in the LA (Fig 1). Results: Patients exhibited lower voltages in the lateral RA (0.43 ± 0.05 vs 0.66 ± 0.06 mV; p < 0.05), and the RA septum (0.46 ± 0.04 vs 0.66 ± 0.06 mV; p < 0.05) compared to the sinus node, respectively. Patients also exhibited lower voltages in the lateral RA compared to the LA roof (0.43 ± 0.05 vs 0.57 ± 0.05 mV; p < 0.05). The difference between the sinus node and the LA roof (0.66 ± 0.06 vs 0.57 ± 0.05; p > 0.05) and other regions failed to reach significance. No difference between combined right atrial voltage and left atrial voltage was found. Differences were maintained for successive time windows over 1 minute. Conclusion: We observed consistent regional variations in atrial voltage in AF patients, and higher voltage in the sinus node than other regions. Future studies should determine if this underlies the link between AF and sinus node dysfunction, and if this varies in comorbidities such as diabetes mellitus.