Abstract 3348: Impact of Left Atrial (LA) Volume Reduction on the Restoration of LA Contraction and LV Function After the Cox-Maze Procedure: Assessment by Magnetic Resonance Imaging (MRI)
Introduction: We have reported that the Cox-Maze procedure concomitant with LA volume reduction facilitates sinus rhythm recovery even in patients with refractory atrial fibrillation (AF) with enlarged LA or long-term duration (e.g. more than 10 years). However, it is unknown whether the procedures can restore effective booster function of the enlarged LA with over-stretched myocardium, and can also contribute to LV function recovery.
Methods: The Cox-Maze procedure in association with mitral valve surgery was performed to 39 AF patients with enlarged LA (diameter ≥ 60 mm). Among them, 21 patients had concomitant LA volume reduction (VR group) while 18 patients did not have LA volume reduction (Control group). Cine-MRI was employed to obtain more accurate LA and LV functions than echocardiography.
Results: Preoperatively, maximum LA volume (MaxLAV, mL), LVEF (%), LV end-diastolic volume (LVEDV, mL), and LV end-systolic volume (LVESV, mL) assessed by cine-MRI were not different between the groups. Postoperatively, sinus rhythm recovery rate was better (table⇓, *p < 0.05 vs. Control) and MaxLAV was drastically smaller (***p<0.001 vs. Control, ‡p<0.001 vs. preoperation) in the VR. Most importantly, among the patients with sinus rhythm recovery in both groups, postoperative LA booster function (emptying fraction (LAEF, %) = [(end-systole LA volume) - (end-diastole LA volume)] /end-systole LA volume) in the VR was far better than the Control (**p<0.01), and LVEF improved only in the VR (†p<0.05 vs. preoperation).
Conclusions: The Cox-Maze procedure concomitant with the LA volume reduction restored booster function of the enlarged LA in addition to LV function recovery and reduction in LVEDV/ESV; however, the Cox-Maze alone did not restore the booster function of enlarged LA with less improvement of LVEF even in patients with sinus rhythm recovery. LA volume reduction may be essential to improve LA and LV function in patients with refractory AF with enlarged LA.