Abstract 700: An Inhomogeneous Edematous Change in the Left Atrial Wall after Radiofrequency Ablation Predicts Early Recurrence of Atrial Fibrillation
An inflammatory response following thermal injury from catheter ablation of atrial fibrillation (AF) may aggravate arrhythmogenic activity and cause early AF recurrences (ERAFs). In 56 patients with drug-refractory, paroxysmal AF (14 women, 60±10 years) who underwent circumferential pulmonary vein ablation (CPVA), cardiovascular magnetic resonance (CMR) was performed before, and 1 day and 1 month after the CPVA. The wall thickness, delayed enhancement (DE) and T2-weighted images of the LA wall were evaluated in 6 subdivided regions of the left atrium (LA; PV ostia, roof, anterior wall, posterior wall, septum, and mitral isthmus). Twenty-three patients (41 %) had AF recurrence within 1 month after the CPVA (ERAF-Gr), whereas the remaining 33 did not (No-ERAF-Gr). Before the CPVA, no region with a high T2 signal was found in any of the patients in either group, and no difference was observed in the total number of DE regions between the 2 groups (2±1 vs. 2±1, p=0.31). One day after the CPVA, high T2-weighted images were detected around the LA wall, and augmentation of the wall thickness of the LA roof was greater in the ERAF-Gr than No-ERAF-Gr group (see Table⇓). One month after the CPVA, the thickened LA wall with a high T2 signal recovered to baseline. On the other hand, the change in the total number of DE regions after the CPVA did not differ between the 2 groups. Shortly after the CPVA, the LA wall was characterized by interstitial edema concomitant with thermal injury, and an edematous change in the LA roof may predict an ERAF. CMR is useful for assessing the distribution and extent of the edematous changes of the LA wall after CPVA.