Transthoracic echo/Doppler in the identification of patients with chronic non-valvular atrial fibrillation at risk for thromboembolic events.

Unlabelled: Left atrial spontaneous echo contrast, detected by transoesophageal echocardiography in patients with non-valvular atrial fibrillation reflects slow blood flow and is associated with an increased risk of cardio-embolism. The purpose of this study was to find echo/Doppler predictors of left atrial spontaneous echo contrast by transthoracic examination. In a retrospective case control study, 17 patients with chronic non-valvular atrial fibrillation who had suffered a recent cerebral ischaemic event (group A) and 17 patients with chronic non-valvular atrial fibrillation who had not suffered such an event (group B) were studied. Both groups were matched for age and sex. All patients underwent standard transthoracic echocardiography with transmitral Doppler as well as transoesophageal echocardiography. Left atrial spontaneous echo contrast was demonstrated by transoesophageal echocardiography in nine group A patients and in two group B patients (P = 0.028); left atrial spontaneous echo contrast was not detected by transthoracic echocardiography in these patients. All patients with left atrial spontaneous echo contrast (11 patients) had a left atrial size, corrected for base index, exceeding 24 mm and a transmitral time velocity integral < 10 cm (sensitivity 100%). Left atrial spontaneous echo contrast was absent in six patients with both characteristics (specificity 74%).
Conclusion: transthoracic echo/Doppler aids in the prediction of the presence of left atrial spontaneous echo contrast and the identification of patients with non-valvular atrial fibrillation with increased cardioembolic risk, thus avoiding transoesophageal echocardiography.