Measurement of left atrial appendage size by transesophageal echocardiography.

Abstract

Transesophageal echocardiography (TEE) is the most common imaging method for evaluating left atrial morphology. Recent advances in 64-slice multidetector computed tomography (64-MDCT) allow accurate measurement of left atrial appendage (LAA) volume. The aim of this study was to evaluate the accuracy of LAA sizing by TEE in comparison with 64-MDCT in patients with atrial fibrillation. Electrocardiogram-gated 64-MDCT and TEE were performed within 2days in 18 consecutive patients (63±9years old, 12 males, 5 paroxysmal atrial fibrillation) with nonvalvular atrial fibrillation. LAA area and LAA volume were measured at end-systole by TEE and 64-MDCT, respectively. The largest LAA area was measured on TEE image. Five patients were in sinus rhythm during examinations. In all patients, LAA was clearly visualized; the largest area of LAA was 9.3±3.9mm(2) and the LAA volume was 21.6±7.5ml. A significant correlation between LAA area and LAA volume was observed (p=0.0003, r=0.75). TEE allows a detailed evaluation of the LAA structure by two-dimensional imaging. LAA size could be evaluated by TEE despite its morphological complexity, i.e., sac-like or multilobed structure.