Analysis of the left atrial appendage morphology by intracardiac echocardiography in patients with atrial fibrillation

Detailed information regarding the structure and dimensions of the left atrial appendage (LAA) is required to guide implantation of LAA occlusion devices in patients with atrial fibrillation (AF). Currently, this procedure is guided by transesophageal echocardiography (TEE). The objective of this study was to evaluate the accuracy of intracardiac echocardiography (ICE) in assessing LAA dimensions. The LAA anatomy was analyzed in 21 consecutive patients (age 62 +/- 9 years, five women, six paroxysmal AF) who underwent catheter ablation for AF. All patients had pre-procedural scans (computed tomography (CT), N = 9; magnetic resonance imaging (MRI), N = 12) of the left atrium (LA). An 8-Fr phased-array ICE catheter was used to obtain images of the LAA. The LAA was visualized with the ICE probe placed sequentially in the right atrium (RA, N = 21 patients), in the coronary sinus (CS, N = 20 patients), and in the LA (N = 21 patients). ICE imaging from the LA showed a LAA ostium diameter of 24 +/- 4 mm and a LAA depth of 32 +/- 4 mm. There was strong correlation between the measurements by ICE and the values obtained by CT and MRI. The LAA was visualized in all cases from all locations (RA, CS, and LA), but complete visualization of the LAA could not be obtained from the RA and the CS in a significant number of cases, preventing accurate measurements. Imaging of LAA using an ICE probe positioned in the LA results in accurate measurements of LAA dimensions. This imaging modality could potentially be used during implantation of LAA occlusion devices as an alternative to TEE.