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 r hythm were studied to compare echocardiographic and hemodynamic charac teristics 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 contra st. Transthoracic echocardiography and transesophageal echocardiograph y were performed in all patients within 1 week of cardiac catheterizat ion study. Group I patients (5 men and 12 women; mean age, 47.7+/-13.1 years) showed smaller mitral valve area, greater transmitral valve pr essure gradient, and absence of moderate to severe mitral regurgitatio n 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, lef t ventricular end-systolic and end-diastolic dimensions, or in left ve ntricular ejection fraction between the two groups of patients. Left a trial appendage function was studied with Doppler in 26 patients. Pati ents (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 c ontractile function, not the LA size, are likely to be more important factors for the development of LA and LA appendage spontaneous echo co ntrast in patients with rheumatic mitral valve disease (predominant mi tral stenosis) who are in sinus rhythm. These findings further substan tiate that blood stasis in the LA cavity and the LA appendage is the m echanism fundamental to the formation of such spontaneous echo contras t.