Acute effect of percutaneous transvenous mitral commissurotomy on ventilatory and hemodynamic responses to exercise. Pathophysiological basis for early symptomatic improvement.

BACKGROUNDImprovement of exertional dyspnea occurs immediately after percutaneous transvenous mitral commissurotomy (PTMC), but the pathophysiological basis for this early symptomatic improvement has not been elucidated.METHODS AND RESULTSExercise hemodynamic measurement and exercise ventilatory measurement with arterial blood gas analysis were performed in 21 patients aged 50.4 +/- 9.5 years (mean +/- SD) with symptomatic mitral stenosis before and a few days after PTMC. Exercise ventilatory measurement were also performed in 14 normal control subjects aged 48.9 +/- 4.9 years. After PTMC, mitral valve area increased (from 1.0 +/- 0.3 to 1.7 +/- 0.3 cm2, P < .001), mean mitral gradient (from 12.2 +/- 5.2 to 5.2 +/- 2.2 mm Hg, P < .001), and mean left atrial pressure (from 18.7 +/- 6.1 to 12.1 +/- 4.0 mm Hg, P < .001) decreased. All patients experienced significant symptomatic improvement soon after PTMC. Comparison of hemodynamic parameters at the same ergometer work rate showed a significant decrease in ...