Left atrial appendage function in mitral stenosis: is a group in sinus rhythm at risk of thromboembolism?

Objective: To study the left atrial appendage (LAA) function and potential for embolization in severe mitral stenosis (MS). Background: Patients with MS and atrial fibrillation or in sinus rhythm develop systemic emboli. LAA function has not been well studied in sinus rhythm. Methods: Forty consecutive patients with MS (valve area ≤0.7 cm2/m2) were studied. LAA ejection fraction and peak emptying velocity were measured along with other data. Results: Patients were subgrouped according to LAA Doppler flow pattern. Group I (n=13) in sinus rhythm had biphasic high velocity ≥25 cm/s. Group II (n=13) in sinus rhythm had biphasic low velocity <25 cm/s. Group III (n=14) in atrial fibrillation had multiphasic irregular flow <25 cm/s or no definite flow. The LAA ejection fraction and peak emptying velocity were strikingly different in all groups. They were lower in group II when compared to group I. Group II had intermediate risk for thromboembolism compared to Group I and III as judged by systemic embolization, spontaneous echo contrast, thrombus in left atrium and LAA. Conclusion: A subset of mitral stenosis in sinus rhythm at increased risk of embolization can be suspected by Doppler transesophageal echocardiographic LAA flow profile.