Haemodynamic effects of exercise in pulmonary stenosis.

Abstract

The hemodynamic effects of exercise were studied in 18 patients with pulmonary stenosis and an intact ventricular septum. Four patients had mild stenosis (RV pressure below 50 mm Hg), 7 had moderate (RV pressure between 50 and 100 mm Hg), and 7 had severe stenosis (RV pressure greater than 100 mm Hg). Five of the 7 patients with severe stenosis (and probably a 1/6 whose actual output could not be measured) had an impaired cardiac output response to effort. All patients with mild or moderate stenosis had a normal output response.As a group, patients with severe stenosis had a lower cardiac output and stroke volume at rest and on exercise and a greater ventiliatory equivalent on exercise than mild or moderate cases. Right ventricular ejection time was greater and ejection rate less in severe cases at rest and during exercise. When the left and right ventricular pressures are similar at rest, the work performed by the 2 ventricles is the same at rest, but right ventricular work is usually a little greater during exercise. Because of the prolongation of right ventricular systole, however, the load on the right ventricle is greater than on the left at right and during exercise.