Relation of Valvular Lesions and of Exercise to Auricular Pressure, Work Tolerance, and to Development of Chronic, Congestive Failure in Dogs

Abstract

In this initial approach to the problem the valvular lesions were limited to the right side of the heart in the unanesthetized dog. The valvular lesions were (a) insufficiency of the pulmonary valve, (b) pulmonary stenosis, (c) combined pulmonary insufficiency and pulmonary stenosis, (d) insufficiency of the tricuspid valve, and (e) the combination of tricuspid insufficiency and pulmonary stenosis. Pulmonary insufficiency alone had little effect on auricular pressure or work tolerance even after mos. of daily strenuous exercise. Pulmonary stenosis of less than 50% of the diameter produced a slight rise in resting auricular pressure, with further rise during exercise. Work capacity was normal. Superimposed pulmonary insufficiency produced only minor changes. One dog with severe pulmonary stenosis had a resting auricular pressure of 100 mm. water. The auricular pressure rose progressively during exercise to 330-400 mm. water. Exercise capacity was temporarily reduced slightly after operation, but soon returned to normal. Tricuspid insufficiency elevated resting auricular pressure by 75-135 mm. water, with slight to moderate increases during exercise. Here again work tolerance was normal and no signs of failure appeared after 3 mos. or more of daily exhausting exercise. The combination of tricuspid insufficiency and pulmonary stenosis produced a syndrome similar to chronic, right-sided congestive failure as seen in man, and characterized by dilated right heart, elevated auricular pressure and distended veins, dyspnea on exertion, decreased work tolerance, hypervolemia, hepatomegaly, ascites and tachycardia. That true cardiac insufficiency was present was suggested by heart-lung prepns.