LEFT ATRIAL SPONTANEOUS ECHO CONTRAST IN PATIENTS WITH RHEUMATIC MITRAL-VALVE DISEASE IN SINUS RHYTHM - IMPLICATION OF AN ALTERED LEFT ATRIAL APPENDAGE FUNCTION IN ITS FORMATION

Thirty-nine patients who had rheumatic mitral valve disease in sinus rhythm were studied to compare echocardiographic and hemodynamic characteristics between those with and without left atrial (LA) spontaneous echo contrast. Patients were divided into two groups according to the presence (group 1, n=17) or absence (group 2, n=22) of the echo contrast. Transthoracic echocardiography and transesophageal echocardiography were performed in all patients within 1 week of cardiac catheterization study. Group I patients (5 men and 12 women; mean age, 47.7+/-13.1 years) showed smaller mitral valve area, greater transmitral valve pressure gradient, and absence of moderate to severe mitral regurgitation compared with group 2 patients (7 men and 15 women; mean age, 47.8+/-14.3 years). There was no significant difference in LA dimension, left ventricular end-systolic and end-diastolic dimensions, or in left ventricular ejection fraction between the two groups of patients. Left atrial appendage function was studied with Doppler in 26 patients. Patients (n=10) with LA spontaneous echo contrast had significantly lower LA appendage ejection fraction (20.34+/-10.76%, vs 34.16+/-13.13%; p<0.05) and lower LA appendage peak emptying velocity (0.17+/-0.09 m/s vs 0.27+/-0.12 m/s; p<0.05) than those (n=16) without echo contrast. It is concluded that obstruction to mitral now and altered LA appendage contractile function, not the LA size, are likely to be more important factors for the development of LA and LA appendage spontaneous echo contrast in patients with rheumatic mitral valve disease (predominant mitral stenosis) who are in sinus rhythm. These findings further substantiate that blood stasis in the LA cavity and the LA appendage is the mechanism fundamental to the formation of such spontaneous echo contrast.