Hemodynamic Response to Exercise in Isolated Pulmonic Stenosis

Abstract

The hemodynamic response to exercise has been evaluated in 13 patients with isolated pulmonic stenosis. The patients could be divided into normal and subnormal groups as determined by the level of cardiac output at rest or during exercise. Those with a subnormal response had right ventricular systolic pressures at rest of 80 mm Hg or more and diminished stroke volumes. The level of the right ventricular systolic pressure at rest may be taken as an index of the degree of alteration in hemodynamics and is therefore a useful criterion in the selection of patients for valvotomy. Additionally, the response to exercise may be helpful in the evaluation of patients with right ventricular systolic pressures less than 80 mm Hg at rest. During exercise all patients except one developed an abnormal elevation of the right ventricular diastolic pressure with no change in stroke volume. These findings have been interpreted as indicating reduced myocardial compliance. A normal response to exercise relative to pulmonary artery pressure was found in all instances but one. Structural alterations in the pulmonary vascular bed presumably accounted for this single exception. Hyperventilation at rest or during exercise usually occurred. The mechanisms responsible for this were not defined by the data available.