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.