Imaging of thrombi and assessment of left atrial appendage function: a prospective study comparing transthoracic and transoesophageal echocardiography

Objective-To compare the value of current transthoracic echocardiographic s ystems and transoesophageal echocardiography for assessing left atrial appe ndage function and imaging thrombi. Design-Single blind prospective study. Patients were first investigated by transthoracic echocardiography and ther eafter by a second investigator using transoesophageal echocardiography. Th e feasibility of imaging the left atrial appendage, recording its velocitie s, and identifying thrombi within the appendage were determined by both met hods. Patients-117 consecutive patients with a stroke or transient neurological d eficit. Setting-Tertiary cardiac and neurological care centre. Results-Imaging of the complete appendage was feasible in 75% of the patien ts by transthoracic echocardiography and in 95% by transoesophageal echocar diography. Both methods were concordant for the detection of thrombi in 10 cases. Transoesophageal echocardiography revealed two additional thrombi. I n one of these patients, transthoracic echocardiography was not feasible an d in the other the thrombus had been missed by transthoracic examination. I n patients with adequate transthoracic echogenicity, the specificity and se nsitivity of detecting left atrial appendage thrombi were 100% and 91%, res pectively. Recording of left atrial appendage velocities by transthoracic e chocardiography was feasible in 69% of cases. None of the patients with a v elocity > 0.3 m/s had left atrial appendage thrombi. In the one patient in whom transthoracic echocardiographic evaluation missed a left atrial append age thrombus, the peak emptying velocity of the left atrial appendage was 0 .25 m/s. Conclusions-A new generation echocardiographic system allows for the transt horacic detection of left atrial appendage thrombi and accurate determinati on of left atrial appendage function in most patients with a neurological d eficit.