DOES MITRAL REGURGITATION PREVENT THE PHE NOMENON OF LEFT ATRIAL SPONTANEOUS ECHO CONTRAST

The aim of this study was to assess the influence of mitral regurgitat ion on the prevalence of left atrial spontaneous echo contrast and thr ombosis in 2,180 consecutive patients undergoing transthoracic and tra nsoesophageal echocardiography. Two groups of patients were defined ac cording to the absence (group I) or presence (group II) of grades 3 or 4 mitral regurgitation quantified by transoesophageal echocardiograph y. Group II was associated with a statistically significant lower freq uency of spontaneous echo contrast (0.6 vs 11.2 %; p < 0.0001), left a trial thrombosis (0.6 vs 4.2 %; p < 0.03), ischaemic cerebrovascular a ccidents (1.2 vs 21 %; p < 0.0001), transient ischaemic attacks (0 vs 12 %; p < 0.0001) and systemic embolism (0 vs 4.6 %; p < 0.01). Conver sely, the prevalence of atrial fibrillation was higher in group II (28 vs 19 %;p < 0.01) and there were more patients with left atrial dimen sions greater than or equal to 5.5 cm (16 vs 6.7 %; p < 0.0001). When mitral stenosis and valve prosthesis were excluded, there were no case s of spontaneous echo contrast (8.3 vs 0 %; p < 0.001) or left atrial thrombosis (2.9 vs 0 %; p < 0.05) in the group with grades 3 or 4 mitr al regurgitation. The phenomenon of left trial spontaneous echo contra st and/or thrombosis is rare in patients with grade 3 or 4 in native m itral valve regurgitation and explains the low incidence of systemic e mbolism in these cases.