Relationship between left atrial appendage emptying and left atrial function using cardiac magnetic resonance in patients with atrial fibrillation: comparison with transesophageal echocardiography.

Abstract

To compare cardiac magnetic resonance (CMR) quantifications of left atrium (LA) function and left atrial appendage (LAA) emptying depending on the presence of LA spontaneous echogenic contrast (LA-SEC) on transesophageal echocardiography (TEE) in patients with atrial fibrillation (AF). A total of 48 patients with AF underwent sequential CMR examination and TEE in preparation for catheter ablation. The CMR protocol included cine and velocity encoding (VENC) sequences for evaluation of both LA function and LAA emptying. The peak blood velocity of LAA just before left ventricle systole was defined as the LAA emptying velocity (LAA-EV). Depending on the presence of LA-SEC on TEE, patients were divided into two groups, the SEC group (n = 15) and the non-SEC group (n = 33). Mean LAA-EV was significantly greater in the non-SEC group than in the SEC group (54.5 ± 24.8 ml/s vs. 26.0 ± 22.6 ml/s, P < 0.01). LAA-EV had a significant positive relationship (P < 0.05) with LAA backflow velocity, as assessed using TEE. Use of an optimal LAA-EV cutoff value of 35 ml/s to predict LA-SEC yielded a sensitivity of 80.0 %, a specificity of 75.7 %, and positive and negative predictive values of 58.8 and 83.9 %, respectively. Using VENC-CMR, LAA-EV is associated with LA function and can be useful for predicting LA-SEC in patients with AF.