Elsevier

Academic Radiology

Volume 15, Issue 7, July 2008, Pages 835-843
Academic Radiology

Original investigation
Preablation Assessment for the Left Atrium: Comparison of ECG-gated Cardiac CT with Echocardiography

https://doi.org/10.1016/j.acra.2008.01.019Get rights and content

Rationale and Objectives

Evaluate the role of two-dimensional echocardiography and electrocardiographically (ECG)-gated contrast-enhanced multislice computed tomographic (MSCT) cardiac imaging to assess cardiac anatomy, specifically pulmonary venous anatomy and left atrial thrombus, in a selected group of patients before catheter-based atrial fibrillation ablation.

Materials and Methods

Left atrial anatomy and associated findings in 34 consecutive patients scheduled for electrophysiologic testing who underwent both echocardiography and ECG-gated 16-slice MSCT cardiac imaging were retrospectively compared. Results from two-dimensional transthoracic echocardiography (TTE), cardiac MSCT, electrophysiologic study (EPS), and transesophageal echocardiography (TEE) (when performed) were taken from the official medical record without prior knowledge of this study when interpretation was rendered for clinical use. Electronic record review included: presence of left atrial thrombus (defined as constant filling defect on at least two echocardiographic views or filling defect on computed tomography) and location, pulmonary venous anatomy, and other cardiac, mediastinal, or pulmonary abnormalities.

Results

Left atrial thrombus was identified by cardiac MSCT alone in five patients (15%). Pulmonary venous variants were identified with cardiac MSCT in two patients (6%). Both MSCT and echocardiography were normal in 17 subjects (79%). Echocardiography was better at identifying associated valvular abnormalities that were seen in 10 patients (29%). Cardiac MSCT angiography alone identified other cardiac and noncardiac abnormalities, including suspicious pulmonary malignancy, mediastinal adenopathy, and coronary stenosis in 15 patients (44%).

Conclusions

Echocardiography and cardiac MSCT angiography often provide complimentary findings during the preprocedural evaluation for patients with atrial fibrillation requiring ablation. Cardiac MSCT may provide significant additional information about the left atrium, mediastinum, coronary circulation, and visualized lung fields. Based on this study, we would advise that patients considered for radiofrequency ablation for uncontrolled right atrial fibrillation have both echocardiography and ECG-gated contrast-enhanced cardiac MSCT performed as part of the preprocedure evaluation.

Section snippets

Materials and methods

After appropriate institutional review board approval, a retrospective review of patients who underwent atrial fibrillation ablation over an approximately 24-month period between early 2004 and 2006 at a tertiary care center was performed. Of the 122 patients who underwent EPS treatment, 34 patients who had both echocardiography and ECG-gated cardiac MSCT angiography before EPS were included. Most patients received full anticoagulation therapy before their clinical workup. Results from TTE,

Results

Over a 2-year period, 34 consecutive patients met inclusion criteria and underwent both cardiac MSCT angiography and echocardiography before EPS studies for uncontrolled atrial fibrillation. Patients included 22 males (65%) and 12 females (35%) with a mean age of 59 years (range 45–77). Documented results of TTE in the electronic records were available for all 34 patients, whereas TEE results were available for 16 patients.

The overall agreement in excluding left atrial thrombus between MSCT and

Discussion

Most patients undergoing EPS evaluation for uncontrolled atrial fibrillation have preprocedural testing to assess for left atrial thrombus and pulmonary venous anatomy. The presence of thrombus in the left atrial appendage increases the risk of systemic emboli (14, 19), which may be precipitated by manipulation of the atrium during EPS evaluation. Likewise, anatomic detail of the configuration and origins of the pulmonary veins may help direct catheter-based EPS treatments. Over the last 2

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