SOME ASPECTS OF DISORDERED PULMONARY FUNCTION IN MITRAL STENOSIS

Abstract

The ventilatory response to exercise in 65 patients with mitral stenosis has been measured in terms of the oxygen ventilatory equivalent (OVE). Elevated values were found in all patients of clinical grade 2 or greater and the degree of elevation was proportional to the functional disability of thepatient assessed according to clinical grading. Following mitral commissurotomy, there was afall in OVE consistent with the clinical improvement. The OVE is considered to provide an objective method of classification of patients with mitral stenosis and of assessing the results of therapy. The exercise pulmonary diffusing capacity determined in 28 patients by the steady state carbon monoxide technique was low in patients with reduced exercise tolerance. No change in diffusing capacity was observed following operation in 12 patients studied. The results suggest the presence of irreversible lung damage in patients with mitral stenosis and it is postulated that this lung damage may be responsible for the failure of some patients to return to normal exercise tolerance following operation.