Coronary Sinus Electrograms May Predict New-onset Atrial Fibrillation After Typical Atrial Flutter Radiofrequency Ablation (CSE-AF)

Background: Complex fractionated electrograms (EGMs) of the coronary sinus electrograms (CSEs) are employed as a target during radiofrequency ablations (RFA) of atrial fibrillation (AF). Anatomically, CSEs includes both of left atrium (LA), coronary sinus musculature and right atrium (RA) electrograms. Aim: To determine the significance of fractionated CSE and delayed potentials as a predictor of new-onset AF after radiofrequency ablation (RFA) of isolated atrial flutter (AFL). Methods: Consecutive patients underwent AFL ablation. Fractionated and/or continuous discrete activities were recorded from coronary sinus electrograms during sinus rhythm and during pacing. Earliest CSE to the S nadir or peak R in milliseconds was recorded and considered as propagation delay for EGMs. Results: Forty patients were included during a mean follow-up period of 55.1± 15.8 months. Twenty patients (50 %) developed AF while the remaining 20 patients maintained sinus rhythm(SR) during the follow-up period. Proximal and mid CSEs were significantly fractionated in AF group compared to group with no AF development (65 % and 60% Vs. 35 % and 30 %, p = 0.03, respectively). However, during pacing from distal duo-decapolar catheter (pole 1-2), distal CSEs alone were significantly fractionated (p < 0.05) compared to SR group. Significant delayed propagation of proximal CSE during pacing and in sinus rhythm were observed in AF group (12.3 ± 9.2 ms vs 7.1 ± 3.6 ms, p = 0.03) and (7.2 ± 2.9 ms Vs 8.1 ± 4.6 ms, p= 0.02) in the same order. Conclusion: Incidence of AF is associated with fractionated proximal and mid CSE in sinus rhythm and distal CSE during paced rhythm after isolated AFL ablation. Delayed proximal CSE propagation is correlated with AF incidence.