Prognostic implication of the left atrial appendage mechanical reserve after cardioversion of atrial fibrillation

Background: This study aimed to demonstrate the long-term prognostic implication of left atrial appendage (LAA) mechanical reserve determined after electrical cardioversion (CV) of atrial fibrillation (AF). Methods and Results: 53 successfully cardioverted chronic AF patients were studied (M/F =40/13, mean age =59±3). LAA emptying velocity (LAAEV) and filling velocity (LAAFV) were measured using transesophageal echocardiography (TEE) before cardioversion, immediately after CV, and with isoproterenol infusion. TEE was done at baseline, 1 month, 3-6 months, and 1 year after CV. At 1-year follow-up, 27 patients remained in sinus rhythm (SR, Group 1) and 26 patients showed AF recurrence (Group2). Baseline clinical and echocardiographic findings were similar between the 2 groups. Immediately after CV, LAAEV and LAAFV decreased similarly in both groups. With isoproterenol infusion, the increase of LAAEV was greater in group 1 than in group 2. Multivariate analysis revealed that the peak increase of LAAEV after isoproterenol infusion was an independent predictor for SR maintenance (odds ratio 1.044, 95% confidence interval 1.014 to 1.075; p=0.0033). Prediction model consisting of the peak increase of LAAEV (>34.4cm/s) and E/A ratio immediately after CV (<2.5) showed a good predictability for SR maintenance (correct ratio 69.8%). Conclusion: This study presents a valid evaluation method for LAA mechanical reserve and demonstrated that LAA mechanical reserve is responsible for the maintenance of SR.