[Significance of atrial fibrillation, left atrial thrombus and severity of stenosis for risk of systemic embolism in patients with mitral stenosis].

The prognostic significance of atrial fibrillation, left atrial thrombus and the severity of mitral stenosis (MS) for systemic embolism was evaluated in 142 consecutive patients with MS (male 61, female 81; mean age 51 +/- 10 years) who were referred for cardiac catheterization. The relationships between systemic embolization, atrial fibrillation, left atrial thrombus and the size of mitral valve area obtained by the echocardiographic or Doppler method, or cardiac catheterization (Gorlin's formula) were studied. The effects of mitral regurgitation (MR) (Sellers II < or =) on systemic embolism or left atrial thrombus were also evaluated. Atrial fibrillation was observed in 117 patients (87%), 30 (28%) of whom had a history of systemic embolism. Four of 18 patients (22%) with sinus rhythm had a history of systemic embolism. Left atrial thrombus was observed in 63 patients (45%), including 17 (27%) with a history of systemic embolism. Seventeen (22%) of 76 patients without left atrial thrombus had a history of systemic embolism. Left atrial thrombus was detected in 17 of 41 (41%) patients with severe MS [mitral valve area (MVA) < or = 1.0 cm2], 8 of 25 (32%) patients with moderate MS (1.1 < MVA < or = 1.5 cm2), 2 of 14 (14%) patients with mild MS (MVA > or = 1.6 cm2), and embolization was complicated in 11% of cases of severe MS, 32% of cases of moderate MS and 21% of cases of mild MS. There was no significant difference between the 3 groups. Left atrial thrombus was more frequently observed in patients without MR than with MR (44% vs 13%, p < 0.05), but there was no significant difference in the incidence of embolism between the groups (28% vs 22%). Positive therapy intervention should be considered to prevent systemic embolism regardless of the presence or absence of sinus rhythm, MR, left atrial thrombus or severity of stenosis.