These included recent congestive heart failure, history of hypertension, previous thromboembolism, left ventricular dysfunction from 2-D echocardiograms, and increased size of the left atrium from M-mode echocardiograms. Given its association with LAA SEC, the low LAA blood flow pattern described herein may become another useful echocardiographic predictor for future systemic embolism in risk stratification in patients with nonrheumatic AF. Such a possibility is worthy of further study.
In the current study, 5 of the 29 (17 percent) patients had mild or moderate mitral regurgitation that was assessed quantitatively by TEE according to the criteria developed by Yoshida et al. The mitral regurgitation may have some influence on the LAA flow Doppler measurement, and this influence needs to be clarified by further investigations. The other problem is the translocation of the LAA during the cardiac cycles. This should be carefully excluded during the determination of the LAA areas, and the simultaneous use of pulsed Doppler recording may be of great help in solving this problem. canadian health&care mall
From the results of this study, we cannot demonstrate higher incidence of LAA thrombus formation in patients with lower LAA blood flow. This may relate to the small number of patients undergoing investigation and more patients should be enrolled in future studies. However, in a previous clinical observation, most left atrial thrombi were accompanied by the presence of SEC. The left atrial SEC was also an independent predictor of left atrial thrombus formation or cardiogenic embolism. The patients with lower LAA flow pattern were found to have a higher chance of LAA SEC formation in this study. Probably, these patients may have LAA thrombus formation in the future if the time of follow-up is long enough.
There are two different LAA blood flow patterns in patients with nonrheumatic AF. The patients with low LAA flow pattern tend to have lower LAA ejection fraction and peak emptying velocity. These patients are associated with having a higher incidence of LA/LAA SEC formation, which had been proved to be a risk factor for systemic thromboembolism. Because of an increased incidence of stroke in patients with nonrheumatic AF, antithrombotic treatment is mandatory. The LAA flow pattern may become another potential echocardiographic factor in deciding which high-risk patients should receive anticoagulation treatment, although this still requires larger prospective trials.