Abstract
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 (Group 2). 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 (>34.4 cm/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. (Circ J 2008; 72: 256 - 261)
