Plasma concentrations of endothelin in bloor from the femoral vein and the antecubital vein were measured in 35 patients with mitral stenosis and heart failure before and after percutaneous balloon mitralvalvuloplasty（PBMV）. The basal plasma concentrations of endothelin in blood from the antecubirtal vein in the patients were significantly higher than those in 32 control subjects （15. 40± 3. 32 vs. 9. 59± 2. 66 pg/ml

P<0. 001）. Plasma endothelin concentrations in patients in New York Heart Association functional classes Ⅱ and Ⅲ were significantly higher than those in control subjects

respectively. The concentrations of endothelin in patients with atrial fibrillation were also significantly higher than those in patients with normal sinus rhythm. Ten to fifteen minutes after PBMV

plasma endothelin concentrations in blood from the femoral vein significantly decreased from 16. 14 ± 3. 34 to 13. 74 ± 3. 78 pg/ml （P<0. 01 ）. Seventy-two hours after the procedure

the concentrations of endothelin in blood from the antecubital vein had fallen to 12. 31 ± 2. 55 pg/ml （P<0. 001 vs. before PBMV and control subjects）. Plasma endothelin concentrations still tended to be higher in patients with atrial fibrillation than those in normal sinus rhythm

but the difference did not reach statistical significance. There were weak but significantly correlations of plasma endothe lin concentrations with the mean left atrial pressure （r= 0. 424

P < 0.001 ）

mean right atrial pressure （r=0. 323

P<0. 01）

mean transmitral pressure gradient （r= 0. 397

P<0. 001）

heart rate （r= 0. 350

P<0. 005）and mitral valve area （r=-0. 454

P<0. 001） in the patients before and after PBMV.