IMMEDIATE AND LONG-TERM EFFECT OF MITRAL BALLOON VALVOTOMY ON LEFT-VENTRICULAR VOLUME AND SYSTOLIC FUNCTION IN SEVERE MITRAL-STENOSIS

To determine the immediate and long-term effect of mitral balloon valv otomy (MBV) on left ventricular (LV) volume acid function, we studied 17 patients (mean age 27 +/- 9 years) with severe mitral stenosis unde rgoing MBV by cardiac catheterization and angiography before and immed iately after MBV and at mean 12 months later. At baseline, LV end-dias tolic volume index (EDVI) was reduced. Ten patients had EDVI less than or equal to 55 ml/m(2), and four patients (23.5%) had LV ejection fra ction <50%. EDVI increased from 60 +/- 17 ml/m(2) to 66 +/- 17 ml/m(2) (p < 0.05) immediately after MBV and increased further to 72 +/- 16 m l/m(2) (p < 0.05) later. Stroke volume index increased from 34 +/- 10 ml/m(2) to 41 +/- 12 ml/m(2) (p < 0.05) immediately after MBV and incr eased further to 50 +/- 11 ml/m(2) (p < 0.001) later. LV end diastolic pressure increased from 12 +/- 5 mm Hg to 16 +/- 4 mm Hg (p < 0.05) i mmediately after MBV and fell to 13 +/- 3 mm Hg at follow-up. LV eject ion fraction increased from 57 +/- 7% to 62 +/- 6% (P < 0.05) immediat ely after MBV and 71 +/- 8% later (p < 0.001). Mean systolic ejection rate increased from 82 +/- 35 ml/sec to 101 +/- 48 ml/sec (p < 0.05) i mmediately after and 165 +/- 81 ml/sec later (p < 0.05). Systemic vasc ular resistance fell from 1887 +/- 525 dyne/sec/cm(-5) to 1280 +/- 231 dyne/sec/cm(-5) (p < 0.001) at follow-up. We conclude that the LV end -diastolic volume and systolic function are reduced in patients with m itral stenosis, and the LV end-diastolic volume is increased immediate ly after MBV and continues to increase at follow-up 12 months later; t he LV ejection performance improves after successful MBV because of an increase in end-diastolic LV volume (preload) and reduction of SVR (a fterload).