Approximately 13–15% of patients with atrial fibrillation have atrial thrombi, usually in the left atrial appendage (LAA). Transoesophageal echocardiography (TOE), frequently used before cardioversion, constitutes the routine clinical tool to detect atrial thrombi.¹ TOE is a safe test,² but may be considered not completely non-invasive, may require sedation, and relies on an experienced operator. The development of alternative imaging modalities to rule out atrial thrombi thus bears potential interest. We therefore evaluated the ability of electron beam computed tomography (EBCT), a computed tomography (CT) technique with high temporal resolution, to visualise atrial thrombi in patients with atrial fibrillation.

METHODS

We enrolled 52 consecutive patients (33 men, 19 women, mean (SD) age 66 (10) years, mean heart rate: 91 (24) minute) with atrial fibrillation of at least 48 hours duration, scheduled for direct current cardioversion. Patients with contraindications to iodinated contrast agent, post-prosthetic mitral valve replacement, in an unstable haemodynamic condition, or unable to give consent were not enrolled. The study protocol was approved by the institutional review board.

EBCT was performed before TOE using a C-150 XP EBCT scanner (GE/Imatron, South San Francisco, California, USA). Fifty cross sectional images of the left atrium were acquired in inspiration (1.5 mm slice thickness, 1.0 mm table increment, acquisition time …