Ventilatory response to exercise in patients with left-to-right shunts.

Abstract

Ventilatory, hemodynamic, and metabolic studies have been performed at rest and during exercise In 34 patients with left-to-right shunts. Most patients showed an excessive ventilatory response to exercise, but this was not apparently related directly to the level of pulmonary arterial pressure or the magnitude of the pulmonary flow. In a minority of patients pulmonary venous hypertension was probably a stimulus to the ventilation. No particular hemodynamic parameter or combination of parameters can thus be shown to be directly associated with the manifest hyperventllation of patients with left-to-right shunts, and the cause of this must therefore be sought elsewhere. The blood gases changed in a manner consequent upon the ventilation. The arterial lactate concentration was excessive in most patients showing hyper- ventilation, and the possible relation between tissue hypoxia and the ventilatory response has been discussed.