Methoxamine-induced increase in afterload. Effect on left ventricular performance in chronic obstructive pulmonary disease.

With a radionuclide technique, left ventricular ejection fraction and stroke volume index were measured in the basal state and after the stress of a methoxamine-induced increase in afterload in 10 men with severe chronic obstructive pulmonary disease. The resting mean left ventricular ejection fraction was normal in all 10 patients. After an acute increase in resistance to left ventricular ejection with methoxamine, the left ventricular ejection fraction and the stroke volume index did not decrease significantly, even in the presence of cor pulmonale in 5 patients. Mean pulmonary capillary wedge pressure was normal before, and did not change significantly after, methoxamine infusion. The data suggest that latent left ventricular dysfunction is not present in this group of patients with severe chronic obstructive pulmonary disease.