Left ventricular ejection performance in mitral stenosis, and effects of successful percutaneous transvenous mitral commissurotomy.

Impaired left ventricular ejection performance was reported in pure mitral stenosis. The speculative mechanisms included insufficient preload, increased wall stress, high right ventricular pressure and unknown myocardial factors, but no definitive mechanism has been established. Fifteen patients with tight mitral stenosis who underwent successful percutaneous transvenous mitral commissurotomy were studied to ascertain whether ejection performance would improve with sufficient blood filling. The indexes of preload (end-diastolic volume) and ejection performance (stroke volume, ejection fraction, and mean systolic and mean normalized ejection rates) were calculated angiographically before and immediately after mitral commissurotomy. Improved blood filling (the result of successful mitral commissurotomy) produced an increase in end-diastolic volume (mean +/- SD 99.0 +/- 30.2 to 112.1 +/- 30.1 ml/m2; p less than 0.05). All 4 indexes of ejection performance also improved. There was good correlation between end-diastolic and stroke volumes before intervention (stroke volume = 0.476 x end-diastolic volume + 16.77; r = 0.76), and the relation between them showed no change even after mitral commissurotomy. It is concluded that both left ventricular preload and ejection performance improved after successful percutaneous transvenous mitral commissurotomy. Insufficient preload could affect ejection performance in patients with tight mitral stenosis.