SIGNIFICANT MITRAL REGURGITATION IS PROTECTIVE AGAINST LEFT ATRIAL SPONTANEOUS ECHO CONTRAST FORMATION BUT NOT AGAINST SYSTEMIC EMBOLISM

The prevalence of left atrial spontaneous echo contrast (SEC) and the occurrence of systemic embolism were prospectively studied in 176 cons ecutive patients. All had significant mitral regurgitation (MR) and un derwent transesophageal echocardiographic (TEE) studies. Left ventricu lography was performed in all patients to document the severity of MR. The underlying causes of MR included rheumatic heart disease in 84 pa tients, ruptured chordae tendineae in 37, mitral valve prolapse in 18, infective endocarditis in 20, coronary artery disease in 8, congenita l heart disease in 5, and dilated cardiomyopathy in 4. No patient was found to have left atrial thrombus. Left atrial SEC was observed in th ree patients (1.7 percent), all of whom had atrial fibrillation, conco mitant mitral stenosis, and huge left atria. Color now mapping reveale d that left atrial SEC was prominent in regions where the turbulent fl ow of MR was not present. Systemic embolism occurred in ten patients ( 5.7 percent), The underlying disease was infective endocarditis, rheum atic heart disease, and dilated cardiomyopathy in 6, 3, and 1 patient, respectively. The sites of embolization involved the central nervous system in eight patients and the spleen in the remaining two. Three pa tients with rheumatic heart disease and the one with dilated cardiomyo pathy were in atrial fibrillation and had dilated left atria (diameter >45 mm) when systemic embolism occurred. Only one patient with rheuma tic heart disease was found to have left atrial SEC. The remaining six , with infective endocarditis, all had sinus rhythm. In conclusion,lef t atrial SEC or thrombus detected by TEE is uncommon in patients with significant MR. Clinical conditions may be of help to identify the sub sets of patients at higher risk for systemic embolism.