Electrophysiological Features of Atrial Flutter Development in Patients With Atrial Fibrillation

INTRODUCTION: Atrial flutter (AFL) is one of the common atrial tachyarrhythmias concomitant with atrial fibrillation (AF). Few studies have investigated clinical factors associated with the incidence of AFL in AF patients undergoing pulmonary vein isolation. The purpose of this study is to investigate the electrophysiological or structural features of AFL development in patients with AF. METHODS: Patients who underwent AF ablation from October 2023 to May 2024 at Tottori University Hospital were analyzed. Transthoracic echocardiography and computed tomography were performed before AF ablation as structural evaluations in all patients. To assess the electrophysiological features, atrial decrement evoked potential (DEEP) at the cavotricuspid isthmus (CTI) was analyzed by extra-stimulus pacing maneuvers from the tricuspid annulus (TA: right atrial free wall) and coronary sinus (CS: right atrial septum) after AF ablation. RESULTS: A total of 91 patients who underwent AF ablation (median age 70 years; 71% male) were included and divided into two groups based on the incidence of AFL (AFL+ group, n = 29 vs. AFL- group, n = 62). There was a significant difference in the incidence of CTI DEEP (p < 0.001) between the AFL+ and AFL- groups. Furthermore, when comparing the incidence of CTI DEEP according to the pacing direction (i.e., TA pacing and CS pacing), only patients with CTI DEEP by TA pacing (TA DEEP) had a significant association with higher AFL incidence (TA DEEP; AFL+ 69% vs. AFL- 11%; p < 0.001). Multivariate logistic analysis showed that TA DEEP was an independent predictor of AFL incidence in AF patients (odds ratio: 1.08; 95% confidence interval: 1.04-1.12; p < 0.001). CONCLUSION: This study revealed that electrophysiological evaluations of atrial DEEP at the CTI were significantly related to the coexistence of AFL in AF patients. TA DEEP was the only independent predictor to identify concomitant AFL in AF patients.