Pulmonary function in pulmonary hypertension.

It has been shown by cardiac catheterization that an increased resistance to blood flow through the lungs occurs in four main conditions: (1) congenital heart disease with potential shunt, (2) mitral valve disease or left ventricular failure, (3) chronic lung disease, and (4) primary and thromboembolic pulmonary hypertension. Although the burden of an increased pulmonary vascular resistance falls almost entirely on the circulation, the primary lesion is probably in the lungs. Up to now little has been written about the effect of pulmonary hypertension on pulmonary function and the object of this paper is to report a study of the mechanical properties of the lungs and the diffusing capacity in a group of patients in whom the presence of a raised pulmonary vascular resistance was established by cardiac catheterization.