Preablation assessment for the left atrium: comparison of ECG-gated cardiac CT with echocardiography.
OBJECTIVE
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.


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.
Department of Radiology, University of Iowa Hospitals and Clinics, JPP 3895, 200 Hawkins Drive, Iowa City, IA 52242-1077, USA.
Stephen J
SJ
Burke
Gaurav
G
Aggarwala
William
W
Stanford
Brian
B
Mullan
Brad
B
Thompson
Edwin J R
EJ
van Beek
D000368:Aged; D001281:Atrial Fibrillation / Q000000981:diagnostic imaging* / Q000601:surgery; D017115:Catheter Ablation; D003287:Contrast Media; D003328:Coronary Thrombosis / Q000000981:diagnostic imaging* / Q000601:surgery; D004452:Echocardiography; D004562:Electrocardiography; D005260:Female; D006325:Heart Atria / Q000000981:diagnostic imaging* / Q000601:surgery; D006801:Humans; D008297:Male; D008875:Middle Aged; D011300:Preoperative Care; D011667:Pulmonary Veins / Q000002:abnormalities / Q000000981:diagnostic imaging*; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed
D003287:Contrast Media