Transesophageal echocardiographic screening before atrial flutter ablation: is it necessary for patient safety?

Background: Transesophageal echocardiography (TEE) is commonly used before atrial flutter (AFl) ablation to detect atrial thrombus (AT) and thereby identify a heightened risk for systemic embolism both in patients with their initial episodes of AFl and in those with prior episodes whose anticoagulation has been inadequate. This treatment strategy has been extrapolated from guidelines for atrial fibrillation. In fact, limited data exist regarding the prevalence or clinical associations of AT and spontaneous echocardiographic contrast (SEC) in patients with AFl. Both AT and SEC are believed to represent risk factors for systemic embolization. This study was designed to provide further insight into the prevalence of these and their associated clinical findings.

Methods: The results of transesophageal echocardiographic examinations in 347 consecutive patients with AFl in whom radiofrequency ablation procedures were planned were reviewed. In each case, specific care was taken to identify AT and SEC. The presence of either AT or more than mild SEC was considered to reflect a thrombogenic milieu (TM). Clinical and echocardiographic data were analyzed to determine the frequency and relevant clinical associations of these two markers of increased thromboembolic risk. In addition to determining the prevalence of AT and TM, the study sought to identify predictors of their presence short of TEE that might allow that procedure to be avoided.

Results: AT were found in 19 of the 347 patients (5.4%). TM was present in 39 patients (11.2%). SEC was associated with reduced left atrial appendage emptying velocity (P < .001). History of myocardial infarction (P = .02) was associated with AT. Reduced left ventricular ejection fraction (P = .01), reduced left atrial appendage emptying velocity (P < .001), diabetes mellitus (P = .02), congestive heart failure (P = .04), and chronic renal insufficiency (P = .05) were associated with a TM.

Conclusions: Allowing for multiple comparisons, the significant markers of the risk for systemic embolization could be obtained only from TEE. Although there are several interesting clinical and echocardiographic associations with AT and a TM, none were strong enough to obviate the need for TEE.