Effect of Pressor Amines on Experimental Intracardiac Shunts and Valvular Regurgitation

¹ Director, Cardiopulmonary Laboratory, Washington Hospital Center
² Stanford Medical School, Palo Alto, California

Experimental atrial septal defects, aortico-pulmonary communications, ventricular septal defects and mitral insufficiency were created in dogs. Arterial indicator dilution curves were recorded before, during, and after the administration of norepinephrine and methoxamine. Alteration of the curves suggests an increase in left-to-right shunting in dogs with atrial septal defects and aortico-pulmonary communication.

An inconstant response followed administration of norephinephrine to dogs with ventricular septal defects and mitral regurgitation. When methoxamine was infused, dogs with ventricular septal defects showed an apparent increase in the left-to-right shunt, and animals with mitral valvular insufficiency had an increase in regurgitant flow.

The findings support the clinical observations of changing murmurs under these circumstances and may be applied during cardiac catheterization studies.